Electricity Saving Tips For Homes And Offices

Ideal Air Conditioner temperature for electricity savings

By on July 29, 2015

Hindi Translation: बिजली बचत के लिए आदर्श एयर कंडीशनर तापमान

Buying an air conditioner once considered a sign of luxury, is now becoming quite common in India. Many urban homes are equipped with air conditioners in one or more rooms. But everyone who owns an air conditioner knows that it comes at the cost of increasing electricity bills. Although cooling does take a lot of electricity but taking effective steps can surely get it down. One of the main things that can help is maintaining the right temperature for the air conditioners.

Air Conditioner Temperature

How does an air conditioner work?

For most people, air conditioner just throws cool air at the temperature one sets it at. But does it really work that way? In fact air conditioner during cooling process, takes the indoor air, cools it  by passing it through evaporator coil and throws it back in the room. It is quite opposite to how our good old air coolers used to work. Air coolers used to take outside air, cool it with water and throw it in. But air conditioners just work on internal air.

How does the thermostat work?

If you set the thermostat at 18oC (64.5oF), does it mean that the air conditioner will cool the room faster than if set at 25o(77oF)? No. The thermostat just checks the temperature of the air inside the room and stops the compressor when the temperature reaches the desired level. This means that the compressor will work longer if the temperature is set to a lower level, i.e it will work more and use more electricity if temperature is set to 18oC (64.5oF) than if it is set to 25oC (77oF). This is because it will take less time for air to reach to 25oC (77oF) than 18oC (64.5oF) as the compressor is working with the same power or wattage.

What happens when the compressor stops?

The air conditioner just blows the fan when the compressor stops and thermostat reaches the desired temperature level. At this stage the electricity consumption is only for the fan which is running and not for the compressor. The compressor will start again when the thermostat detects that the temperature has increased again from the levels that are set. Compressor is the most electricity consuming component of an air conditioner.

What factors impacts electricity consumption of Air Conditioner?

There are 4 factors that influence the electricity load:

1) Indoor air temperature

2) Outdoor temperature

3) Thermal insulation of the room

4) Temperature setting of the air conditioner.

If the difference between temperature desired and indoor/outdoor temperature is huge, then the air conditioner will need lot more electricity to cool the indoor air to desired temperature as the compressor will run for longer duration. If the temperature is set at 18oC (64.5oF) and the outdoor temperature is 38oC (100oF) then the electricity required will be lot more than when thermostat temperature is 24oC (75oF) and outdoor temperature is 38oC (100oF). As per study by ACEEE (American Council of Energy Efficiency Economy), increase of each oC can save 3-5% of units consumed. This can considerably bring down the units consumed per month in the electricity bill.

What is the ideal temperature that should be set on thermostat?

Having said that, increase in temperature does not reduce the comfort level. In fact as per ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), the ideal temperature for thermal comfort is between 23.5oC (74.3oF) and 25.5oC (78oF) in summers (depends on several factors as listed on wikipedia). Thus setting the temperature to 24oC (75.2oF) saves on electricity bill and provides good comfort. Using ceiling fans along with air conditioners can additionally help in increasing the thermostat temperature.Air Conditioner Temperature Infographic

Does “Quick Cool” option in Air Conditioners help?

Setting an air conditioner to quick cool sets it’s temperature to 18 or 16 oC (64.4oF or 60.8oF. This means that the compressor stops only when indoor temperature reaches this level. But while coming down from 35 or 40 oC (95oF or 104oF) it would have surely crossed 24oC (75.2oF) which is a comfortable temperature. So using “Quick Cool” option does not help because more electricity is used to get the temperature down to 18oC (64.5oF) whereas compressor would have stopped in between if the temperature was set to 24oC (75.2oF) thereby consuming less electricity.

How do old air conditioners without thermostat work? 

Old air conditioners without thermostat have high, medium and low cool options. As we learnt earlier that compressors of air conditioners work in binary mode (either they are on or off), an air conditioner without thermostat does not control air temperature. The high, medium and low options just changes the air conditioner fan speed. High means that air conditioner will throw more air and low means that the fan speed will be slow. The options do not change the temperature of the room, nor do they change the electricity consumption.

Here is a short video for tips to reduce power consumption of air conditioner in India



  • srini

    How much time required for 1.5 ton ac to reach 20*c in a small room

    • Bijli Bachao Team

      Will depend on the size of the room, cooling capacity of the AC, outside temperature, things inside the room, appliances in the room, etc.

  • Ashi

    Hi, Recently we are using AC 1.5 ton 3 star since long time on fixed 28 degree in auto mode & earlier my Bill was max to max reach to Rs.2500-3000 but in last Month, my bill been increased drastically in very high side of Rs.9754 in same usage of AC or other Appliances in same mode. Pls. suggest on this urgently.

    • Bijli Bachao Team

      Hi Ashi,

      Is it a one month bill or does it include arreas (previous bill)? ACs can certainly increase bills, but it is difficult for it to increase the bill 3 times if the usage has remained the same. Also the previous month was June which was not as hot as May. Can you send a copy of your bill at [email protected] ? Also if you can provide us the list of appliances in your house and their daily usage along with it, then it would be great.

  • jraju

    I have raised 3 questions but i do not find any one on my next day of browsing this site. What has happened to those

  • akash

    hi,
    i live in Kolkata.
    ac model:ah-xp13pmt 1.1 ton inverter SHARP.(it does not have heating function,it has only cooling capability).

    my questions are:
    1:let’s say the outside temp is 21c and i set the thermostat at 28c normal cooling mode,then will the compressor still run?or just the fans?

    2:it’s rainy season,and let’s face it,it’s acid rain.so i am worried about my outdoor unit being deteriorated.
    is there some ways i can maintain that?for eg:by washing it with pure water or something like that?

    thanks.

    • Bijli Bachao Team

      Hi Akash,

      Here is our response:

      1) In that case only the fan will run. Compress will not run.

      2) You can protect the outdoor unit from direct rain by covering it from top, but still humidity will impact it. Try to see if you can get an AC engineer who can do corrosion protection coating on the outdoor unit. That is the best that you can do.

  • Vidit mehta

    Hi I have bought 1.5 tonsplit ac for a 250 sq ft room of Hitachi company but since installation my usage has been for night times only but now my normal electricity bill has gone up to 3000 which earlier use to be 800 rs. Kindly guide me with ideal mode for usage and temp. To be set so I can save on my bill amount. I live in mumbai. I noramly keep temp at 21 degrees and keep it on auto mode.

    • Bijli Bachao Team

      Hi Vidit,
      We recommend people to keep the Ac temperature at 25 degree as below that the consumption of electricity of the AC increases. We recommend you to keep the AC on cool mode with temperature of 25 degree or above.

  • Siddharth

    Hi BB team ,
    I have a room of size = 12X21=252 sq. ft on first floor cieling is exposed to Sun. I was told to purchase a split Ac of 2 ton and not a window AC of 2 ton by a technician of AC. When I asked the technician of why not purchase a 2 ton window AC when it is lesser in price ,easy to install , Power Consumption is nearly Same and moreover the btu Cooling of both window n split is same.
    He told that in 2 ton split AC the condensor coils are large and the gas Condensation is easily done in large coils so the cooling is very fine.
    Whereas in a 2 ton Window AC the condensation Coils are small and the gas is not condensed easily so in 2 ton Window the Cooling fails.
    Please give correct advice on whether to purchase a split unit or a Window unit of 2 ton ?

    • Bijli Bachao Team

      Hi Siddharth,

      Although I cannot tell if 2 ton AC is right sized for you or not but our suggestion would also be to go for split AC. Here are some points supporting the same:

      1) BEE star rating of window ACs is 1 level lower than Split ACs. So a BEE 5 star rated window AC would be same in power consumption as BEE 4 star rated split AC.

      2) There are not many electricity efficient options available in 2 ton window ACs. At best you can get BEE 2 or max 3 star rated window AC which will be equivalent to BEE 1 or 2 star rated split AC.

      Cooling depends on the cooling capacity and it does not vary much with window or split. A larger cooling capacity AC will cool faster. And the tonnage is representation of cooling capacity.

      Would suggest you to look at these two videos:

      https://www.youtube.com/watch?v=Qx7kgN87i3I

      https://www.youtube.com/watch?v=rZEiUjwr5ds

  • Sathish kumar

    I am using Blue Start A/C 1.5 ton, 5 star. My room size is 14/14. I am using the ac at 30. Will it consume more power.

    • Bijli Bachao Team

      If you run it at 30 then it should not consume more power.

  • christopher Foo

    How to maintain office room temperature at 24 degree celcius of 600 sq ft? How many hp aircon needed?

  • Kartik

    Sir, i live in top floor in delhi. My landlords have given me an AC but have disabled the power save mode(obviously). The meter is also there. How do I minimize the meter reading? The meter runs faster than usain bolt. :|

    • Bijli Bachao Team

      How can someone disable power saver mode?? Is it not there on your AC’s remote control? There are lot of ways using which you can save electricity in your home. First and foremost get a white roof i.e. get the roof top painted with white reflective paint. It will significantly reduce heat in the room. You can also put extruded polystyrene boards on the ceiling (as false ceiling) and it will reduce the heat in the room. You can refer to our insulation section for more information: https://www.bijlibachao.com/save-electricity/insulation

  • Tapas Roy

    I have purchase a 1.5 ton AC, make carrier. 3 star. My house size is 12’x 12′. I leave at west bengal. I have to run my ac for 4-5 hours per day (maximum) only for summer session. Is my decision right or otherwise. Please answer me.

    • Bijli Bachao Team

      Hi Tapas,
      If your room is on top floor your room requires a cooling of 1.5 tons. So a 1.5 ton AC is ideal for your room and your usage is quite low so a Carrier 3 star AC is good for you. Also Carrier is a good brand so it is a good buy.

  • ashutosh

    Sir,I bought blue star 1 ton 5 star split ac…at starting it works fine but now when I turn off the ac by remote..a cracking sound come from the indoor unit like internal body is broking but when I turn off by main switch..its okkk.no sound coming…is there problem or not…and one more thing that left side of air wing not blow air properly….i have clean the filter but air not coming properly from the left side of the wing…what’s the problem

    • Bijli Bachao Team

      Hi Ashutosh,

      You may have to call up Blue Star engineer to look at it properly. It will be difficult for us to suggest anything sitting remotely.

  • jraju

    How to find that the compressor stopping stage, if one has set , a set degree temperature. I ask this question, because, the compressor is outside the room. Is there any indication light that will show, only fans are running.

    • Bijli Bachao Team

      Hi,

      You need to listen to the outdoor unit. There is no indication in the indoor unit. The outdoor unit will make more noise when the compressor is on.

    • jraju

      There should be something indicating to this effect. OK researchers will have to think about it. I am having 2ton inverter ac. If i select 26 , and select sleepmode, how much units of current will it take. it has the cooling capacity of 3550watts and power consumption of 1080 watts/ How to calculate the unit of power consumption for this ac if one selects sleep mode in it.
      i learnt that sleep mode reduces consumption of electricity. I am asking this , as i do not find any other topics that relate to this

    • Bijli Bachao Team

      In Sleep mode the AC increases the thermostat temperature by 2-3 degrees throughout the night and that’s how it decreases electricity consumption. At a very high level approximation your AC would consume about 0.7 units of electricity per hour at setting of 25. With each degree increase you should get about 5-6% saving (approx).

  • jraju

    How to maximize the ac benefit of voltas inverter ac. In which mode one use the 2 tonne ac. what is special about the word inverter in it

    • Bijli Bachao Team

      Hi jraju,

      We have given a lot of details on the inverter technology on these articles:

      https://www.bijlibachao.com/air-conditioners/air-conditioners-with-inverter-technology-can-help-save-electricity-ac-india.html

      https://www.bijlibachao.com/air-conditioners/difference-between-a-bee-5-star-rated-and-inverter-technology-air-conditioner.html

      reading these may help.

  • jraju

    Could you allow downloading the tips video

    • Bijli Bachao Team

      It is on youtube. Youtube does allow offline viewing on mobile phones.

  • om beniwal

    If I have my AC temperature on 28’c is it will consume less or high electricity.

    • Bijli Bachao Team

      It will consume less electricity at 28.

  • Payal Aggarwal

    What would be the consumption per hour if the temperature is set between 24-28 for at least 7-8 hours per day.

    • Bijli Bachao Team

      It will depend on multiple things:

      1) Tonnage of AC and its power rating.
      2) Size of the room (AC cools indoor air and the volume of air has to be measured)
      3) City (as some cities are hot and AC has to work harder and some are not that hot and the AC has to work less).
      4) People in the room (more people means more heat in the room and thus more cooling).
      5) Insulation in the room ….. etc etc etc …..

      It is hard to get exact number but if you can tell the tonnage of the AC, its power consumption (if not power consumption then brand and model no), size of the room, city, then we can make a guess.

    • Payal Aggarwal

      I have Volta’s 1.5 ton 3 star window AC. I live in delhi. And stay alone … Want to know what would be the energy consumption if AC is used for 7-8 hours at 24-28.

    • Bijli Bachao Team

      Hi Payal,

      A BEE 3 star 1.5 ton AC would consume 1.5-1.7 units of electricity in an hour. In 7-8 hours it would consume about 12-15 units.

  • Darwin

    Hi BBTeam,

    I need an advise from you. I have recently bought a 1.8T 3 star Daikin AC (FTC60QRV16 – Rated Power input is 1970Watt) for my 13*14 room on first floor with direct sunlight, city Noida.
    I observed that if I set temp at 23-24 then it consumes power @3unit/Hr rate (as reading increased by 21 unit while AC ran for 7 hours at night) while if I set temp to 27-28 then it consumes @rate of ~1.3unit/Hr (as reading increased by 10 unit while AC ran for 8 hours at night).

    So is this AC working as expected or consuming more power than expected while we set at low temp? Also Isn’t it that it should consume MAX ~1.97unit/hour as per rating?

    • Bijli Bachao Team

      Hi Darwin,

      1.3 units/hr sounds reasonable …. but 3 units/hr sounds quite high ….. it should not be like that … It should be approx 22-25% higher at 23-24 as compared to 27-28. But that will not make it 3 units/hr. Are you sure it is consuming 3 units/hr?

    • Darwin

      Yes its taking 3 units/hr. and sadly when I called daikin technician he just checked the current ampere running n found it normal. now they r saying me that machine is working fine nd power consumption is ok bcoz of normal ampere current. plz suggest..

    • Darwin

      Team, please provide some suggestion.. and tell me that if even in extreme case unit should not go as high as 3 units/hr? Do you really think that there is an issue.. if yes can you please suggest what could be the root cause?

    • Bijli Bachao Team

      Hello Mr Darwin,

      It will be extremely difficult for us to tell the root cause sitting remotely. May be the AC is not installed properly (vacuum not done while installation or gas pressure is not right). But 3 units/hr does not look right. At 6-7 Amp current it should consume 1.3-1.4 units per hour.

    • Darwin

      Thanks for your suggestions Team.. I will look into the points you have mentioned.. Can you please explain me more about vaccum and gas pressure. Tomorrow technician will visit so can I ask him to check these things?

    • Bijli Bachao Team

      Daikin FTC60QRV16 uses R22 …. typical pressure for R22 AC is 70 psig. Vacuum is done to remove any humidity present in the system.

    • Darwin

      Now, I am bit confused because in the body of outdoor unit there is a big label of R32 and also in the specification pdf file of FTC60QRV16 attached in Daikin website it is mentioned that Refrigerant gas is R32. Please advise

    • Bijli Bachao Team

      Sorry, my bad, it is R32 only. Also R32 has similar working pressures as R410A so it should be about 120 psig.

    • Darwin

      Just to add here that mentioned Operating current is 9 in the specification pdf file of FTC60QRV16 which I found in Daikin website: https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&ved=0CD4QFjAIahUKEwiX94r4mpTGAhUGNLwKHSQeAAI&url=http%3A%2F%2Fwww.daikinindia.com%2Fsystem%2Ffiles_force%2FSpecification%2520product%2520pdf%2FFTC_specs.pdf%3Fdownload%3D1%26download%3D1&ei=9BWAVZetIYbo8AWkvIAQ&usg=AFQjCNFVCt64hQEm7QeQ2W1xkK8YDGjUUA&cad=rja

    • Bijli Bachao Team

      Even with operating current of 9 the VA value would be 220 x 9 (at 220 Volts) = 1980 … and assuming power factor of 0.9 the wattage would be 1980 * 0.9 = 1782 …. also this is the peak power consumption when the compressor is on …. and compressor should not be on 100% of the time unless it is undersized … assuming it is undersized … 1782 watts means 1.78 units per hour …. but if it is right sized then compressor would be on only 70-80% of the time … so power consumption should be 70-80% of that …. 3 units/hr is extremely high.

    • Bijli Bachao Team

      3 units/hr is not right. And if the running current is right when the compressor is on then there should be no reason why it should consume 3 units/hr. It should consume about 15-16 Amp consistently to consume 3 units/hr. Was it that high? Was anything else also “on” in your house when you measured increase of 21 units in 7 hrs?

    • Darwin

      When they checked Current was ~6.2Amp (max) only. No other device was ON at night except refrigerator which I dont think make any difference. Then what can cause this much high power consumption? Please suggest

    • Darwin

      Is there any possibility that because it is 3 star AC so consuming more power? We are two people living in this room and room has one big window also of size 8*7 facing West. Room is under sunlight from two sides and floor.

    • Bijli Bachao Team

      No it is not possible. A 3 star 1.5 ton AC should not consume 3 units of electricity. There is something wrong somewhere.

    • Darwin

      It is 1.8 Ton AC.

    • Darwin

      No it is 1.8 Ton AC .. plz tell me if this is wrong even with 1.8 Ton AC also?

    • Bijli Bachao Team

      Yes. Even with 1.8 ton AC, 3 units/hr is not right.

    • Bijli Bachao Team

      6.2 amp is about 1.3-1.4 units of electricity consumption. 3 units does not look real. You can check the exact consumption using a Kill a Watt meter as available on ebay: http://www.ebay.in/itm/Meco-Energy-Meter-PG09-Killawatt-Energy-Metering-Power-Guard-Kill-A-Watt-/151235972948

    • Darwin

      OK but I have re-checked power consumption @day time also and it took 9 units for 3 hrs. Also one thing that it is a sub-meter so can there be any reason bcoz of this?

    • Bijli Bachao Team

      Can you get your submeter changed or checked for efficiency? Also as I said you can either get a kill a watt to measure your AC or you can get another sub meter and get it fabricated as mentioned on this link to measure your AC: https://www.bijlibachao.com/assessment/measuring-electricity-consumption-of-home-appliances-and-doing-self-audit.html …. Kill A watt is sophisticated and would cost you about Rs 2000. But you can get a sub meter for Rs 200-300 and pay another Rs 100 to get it fabricated.

  • GANESH

    what is the Normal cut off time of compressor of 1.5 ton split AC to bring down the 130 sq feet room temp from 32 deg to 24 deg

    • Bijli Bachao Team

      Ideal cycle time for a right sized AC should be 9 mins (to achieve optimum efficiency as we have mentioned on our article: https://www.bijlibachao.com/air-conditioners/understand-cycle-time-of-air-conditioners-frequency-with-which-ac-compressor-turns-off-and-on.html ). However cutoff time will depend on the heat load in the room which will depend on various factors: outside temperature, people in the room, appliances in the room, furniture in the room, things kept in the room, wall colors, etc.

  • ashutosh

    Sir I bought blue star 1 ton 5 star split ac…my room size 10*12….roof of the room direct facing sunlight….2 window…and 2 doors…one door and one window always closed… waals is not facing sunlight….no heating appliance in the room….no. Of people in the room is 4…main problem is I set my ac in auto mode and it shows temperature in display is 25….but temperature is not going down below 29 to 30 degree Celsius in day time…..outside temperature of my city is around 45 to 48 degree…outdoor unit is in shading place temporarily…at night temperature is going below 27-26 degree..is my ac having problem or is it undersize

    • Bijli Bachao Team

      Hi Ashutosh,

      Which city are you from? Firstly thermostat temperature is temperature of Air close to the AC, if you try to measure temperature too far from the AC then it will certainly be less. Can you make sure that the AC fan speed is high or there is circulation of air in the room? This will make sure that the cool air mixes and reduces the temperature of the whole room. Also if your room temperature is not going below 25 even at the lowest temperature setting (even with good air circulation) then it is certainly undersized. If your room’s roof is directly under the sun then avoid using ceiling fan for air circulation (table fan or pedestal fan are better), however if there are more floors on top of the room then try using ceiling fan for better air circulation and to reduce air temperature through out the room.

    • ashutosh

      Sir I m from Allahabad….how could I know air circulation in the room….on day time temperature not going below 30 even at the lowest temperature setting…..by using fan, can I reduce the room temperature….ac fan speed is also high…at night, temperature going down quickly to 27-26..when it set to 25….also using turbo mode on day time

    • Bijli Bachao Team

      Hi Ashutosh,

      Your AC is undersized for your room. As per our calculations your room needs 1.4 tons of cooling during peak summer day time. And 1.4 tons of cooling is required to bring down the room temperature to 25. So your problem is that the AC is undersized for peak summer day time.

  • pritam

    If I set ac to 20°c then I reset it to 25….will it consume significant amount of
    electricity again as compressor would work to reach 25°c

    • Bijli Bachao Team

      Hi Pritam,

      It will not consume electricity as the compressor will turn off when it does not have to reduce temperature. Changing from 20 to 25 is as good as switching off the AC. It does not need to work at all. It only works to reduce temperature.

  • Udbhav Tiwari

    I have just bought a Whirlpool 1.5 ton AC with 5 Star rating. I wanted to ask is it able to cool a room of 15*10 dimensions and MORE IMP How much time it would need to cool my room to 22 degrees APPROX Plzz reply

    • Bijli Bachao Team

      Hi Udbhav,

      A lot depends on the external temperature in your city, things kept in the room, number of people in the room, etc. If 1.5 ton AC is right sized for your room then it should give sufficient cooling till 25 degrees in an hour. However to get to 22 it will take some time. Also if it is undersized then it may not even reach temperature of 22 degrees.

      Which city are you in? Also is the room top floor or lower floor (is ceiling exposed to direct sun)? Do you get direct sunlight on the walls? How many people will be there in the room?

      By the way 22 is quite cold!! Even 25 is decent cold!

  • GURPREET SING

    i have bought carrier 1.5 tonne 3 star in last month, i don’t run ac on regular basis. my office is in delhi, the temperature you know very well, its now peak time of summer.

    my question is should i use it regular basis or i do take breaks like the way i am doing ( i switch off ac after using 1 hr or half when i need after that my office starting to be hot. after than i turn it on at 18 deg C), what is the impact if i use or take break on ac as well as electricity consumption.

    my second question is my office space is near about 200 sq ft.. i have purchased 1.5 tonne is this sufficient according to the area?

    • Bijli Bachao Team

      Hello Mr Singh,

      There should be no impact on the AC performance if you switch it off periodically. In fact there are programmable timer switches (as mentioned on: https://www.bijlibachao.com/general-tips/time-switches-easy-automatic-way-to-switch-on-and-off-appliances-and-save-electricity.html) that are available in market that you can use with your AC to programmatically switch on and off the AC to save electricity. You can switch it on for 15 mins and then switch off for 30 mins, then again switch on for 15 mins and switch off for 30 mins. This can certainly save electricity and will not break your AC.

      1.5 ton looks slightly undersized for 200 sq ft. However if you feel comfortable with this AC then let it be there. Undersizing is never a problem with electricity consumption of AC. In fact it is better if you can undersize and still remain comfortable.

    • GURPREET SINGH CHUG

      thanks, i really appreciate for your reply and quick response within few days.

  • omi

    I have purchased 3 days back godrej 1.5 ton 5 Star ac for 120 S.ft room, I feel it is not chilling fast even running at 16 degree, in day and as well as night. How to check that ac is running well or with some fault. Please reply.

    • Bijli Bachao Team

      1.5 ton sounds oversized for 120 sq ft room (unless you live in north and your ceiling gets direct sunlight). It should cool super fast (as it has more cooling capacity). Have you tried increasing the fan speed of the AC? If you have and it is still not cooling well then it is possible that the installers did not fill in the refrigerant gas properly while installing.

  • Sachin

    Hi BB Team, I have purchased 1 ton Samsung Neo Series AR12JV5HBWKNNA Inverter AC, on which degree Temperature set by AC will save electricity more.
    Please help. Or how to auto set thermostat at that level.
    Thanks, Sachin ,Patna

    • Bijli Bachao Team

      You should not keep it lower than 24-25 if you want to save electricity.

  • Tinu

    hello team.
    I am having a whirlpool 1.5 Ton 3 star AC since 2011. Those days it worked fine even in summers at temperatures above 42 deg C. But since last year in summers, whenever i used to turn on the AC arround 12pm it ran fine upto some time..then got tripped off and it went on. It tripped every 2-3 minutes after the compressor starts. However, the AC works fine during night time. Last year i got it checked by an engineer but still then the problem persisted to some extent. This year same thing is happening. I also have tried to cool down the condenser ( thinking it to be due to overheating of condenser at 42 deg C) by putting some cold water over the fins of condenser part, but still facing the same problem. The complaint regarding the matter has been registered but they are yet to attend it. PLEASE HELP..!!

    • Sri

      Hi @tinu.. I am from chenni and have a 1.5ton LG AC system. It also has the same problem. It works very well at night, but during scortching sun it does not cool :)

    • Bijli Bachao Team

      Hi Sri,

      Is the AC throwing Cold Air and your room is not getting cooled enough or is the AC not throwing any cold air at all. If the AC is throwing cold air then the AC may be undersized for the room. If the AC is not throwing any cold air then you may try throwing some water on the outdoor unit to make it work temporarily. You may also plant some plants around it or put some shade on top of it to avoid direct sunlight. It should work well in such case.

    • Bijli Bachao Team

      Hi Tinu,

      Are there any voltage problems in your area during day time? Are you using a voltage stabilizer? It can also happen due to voltage fluctuation. May be the AC is drawing a lot of current and somewhere it is not getting enough and it is tripping.

  • piyush

    sir my Voltas 1.5 tonne 3 star AC bought 1 month ago…tried to test…not cooling below 22 degree centigrade.ran for 3 ours still temp dint go below 22 degree :(

    • Bijli Bachao Team

      Hi Piyush,

      How much temperature do you want your AC to cool down to? 22 is quite cold!!

  • Jose Antonio Eguaras

    what is wrong when you set the desired room temperature to 25 degress celcius at about 6.00 pm and after 8 hrs or at 2.00 am the room temperature on the remote is 26 degress and the compressor has NOt knocked off since ithe aircon was set on. The room seems to be colder than the 25 degrees at 2 am

    • Bijli Bachao Team

      Well what you are observing can certainly happen. The thermostat of the AC is in the indoor unit and it senses the temperature of the air close to the indoor unit. However the temperature is not the same everywhere in the room. ACs have a limited impact (unless you switch on the fan to increase air circulation). The temperature increases as you move farther away from the AC. There are some ACs that have ifeel technology where the thermostat is there in the remote control. In that the AC is controlled on the basis of temperature in the remote.

      And by the way 25 or 26 degrees is quite cold. At 2 AM the AC would be really close to 25 degrees, at 6 PM it would be 27-28 and not really 25 (in 1st hour of operation).

  • gaurav

    Hello sir. …as you told earlier that lloyd ls18gri will consume 1.2 unit per hour in night but it is consuming 10 units for running 5 hrs at temp set at 26….room size is 15×13 it has no floors up …I m not running ceiling fan as it is giving hot air. ….is unit consumption is ok? ???? Or there is some problem

    • Bijli Bachao Team

      Hi Gaurav,

      A 1.5 ton inverter AC consuming 2 units in an hour is extremely high. It should not be the case. Looks like either the AC is faulty or it is running at peak capacity for most of the time. As per your room size and setup you need about 2.3 tons of cooling during peak summer day time. At night it should be about 50-75% of it so about 1.2 to 1.7 tons at night. If the room is quite hot then it is highly likely that it would be around 1.7 tons and in that case the inverter AC will run at peak capacity. But still it should not exceed 1.5-1.6 units per hour. You may ask Lloyd to send an engineer to check the same.

  • lakshmi

    How much power will be consumed when we keep that ac in 28 degrees for the whole night?

    • Bijli Bachao Team

      It will depend on the size of the air conditioner, size of the room, number of people in the room, appliances running in the room, things kept in the room, etc. Would suggest you to go through this link on our website: https://www.bijlibachao.com/air-conditioners/things-that-impact-electricity-consumption-in-air-conditioners.html

    • Ujjwal

      Hi sir please suggest me can I save electricity if I set my 4 star lg split Ac in 27/28 till 30 degree as I am comfortable with this temperature as well than going 20-24 degree .

    • Bijli Bachao Team

      Hi Ujjwal,
      Yes you can save electricity if you set the temperature at 27/28 or till 30 degree. In fact we recommend people to keep the temperature of AC above 25-26 degree to save electricity.

  • abhi

    My Samsung Aircons compressor doesn’t cuts off?is there a problem with condenser?

    • Bijli Bachao Team

      Depends on multiple things:

      1) Is it an inverter tech AC? If yes then it mostly won’t cut off.
      2) Is your AC undersized for the room? If yes then again it will not cut off or cut off less frequently.
      3) There can be a problem with the compressor.

  • Dixit Arora

    Hi team,

    I bought the voltas 1 ton window a.c three days ago. After installation of unit I find that the adjacent wall vibrates too much. I call for engineer from voltas. He havent visit yet. I have run the a.c for whole last nite, it doesn’t cool to my expectation. Does it have problem with it compressor.

    • Bijli Bachao Team

      Hi,

      Which city are you in? What is the size of your room? Also does your room get direct sunlight on the ceiling (is your room top floor)? Does it get direct sunlight on any of the walls? Do you have big windows in your room?

  • ram Mahto

    hello,
    I bought a split AC last year of capacity 1.5 ton. I have a doubt that this AC is not cooling on time and more time is being taken by ac to cool the room. The AC is set at 16, and it took 35 minutes to bring down the temperature from 34.7 to 25 degree celcious. Is it taking right time or is it taking more time…???

    Thanks and Regards
    Ram

    • Bijli Bachao Team

      Hi Ram,

      It is taking right time. Also the thermostat is in the indoor unit, so when you set it to 16, it would sense the temperature close to the indoor unit. Unless you have good air circulation in the room, the whole room will not cool down to the same amount.

  • srijith

    I am using voltas 1.5 ton 5 star split ac. Want a clarity on one thing.if at all I am switching of the ac through the remote where as I am not switching off the main power will electricity consume or not !

    • Bijli Bachao Team

      Hi Srijith,

      It may have 1 or 2 watt power consumption (or may be less) just to keep the circuitry active. In past we had measured some window and split ACs and had quite varying results. Max we saw some window ACs consuming about 5 watts. We even observed some split ACs not showing any power consumption as well. It will not be high amount but still there is possibility that there is some.

    • Srijith

      Thank You.

  • Kendrick Triplett

    I’ve been searching the internet but I have not been able to find an answer to this problem: I live in an apartment building. My AC unit works beautifully throughout the day. I keep my thermostat set to about 72 degrees Fahrenheit (the thermostat is analog so I eyeball it). Majority of the time my family find that setting a little uncomfortable and they push thermostat up to about 77-78.

    The problem arises at night. Using the same temperature settings my AC unit do not seems to condition air the same way at night that it does in the daytime. That prickly feeling you get when it’s a tad bit too cold, doesn’t happen at night. I’ve took in consideration that it’s naturally cooler at night and the unit might not cycle on as much, but I live Texas and there are hardly any “cool” nights. I’ve even gone as far as checking my own body temperature to make sure I wasn’t running a fever or something. My family that is normally prickly during the day are extremely comfortable at night under these same settings. It may be nothing, but if you are familiar with this phenomenon, any feedback would be greatly appreciated.

    • Bijli Bachao Team

      Hi Kendrick,

      From what you mentioned its either a problem with the thermostat or leaky refrigerant. Did you call up an engineer to check it up?

  • sameer

    I am having a 1.5 ton a.c.If I set the temperature at 18 then the auto cut off is taking place after every 2 mins & if the temperature is set at 25 then auto cut of takes place after 10 seconds. Kindly suggest what Wil be the reason for this?

    • Bijli Bachao Team

      Hi Sameer,

      Which city are you in and what is the size of your room? 2 mins is quite short and 10 seconds is super short ….. Ideally if the compressor runs for 9 mins then that is ideally sized AC. Else it may be oversized AC.

  • gaurav

    Thanks for replying ……my room size is 15×13×10 and no floors up but same ac is working well in same conditions. …sir I m not satisfied. ..kindly suggest what to do. …..its just cooling like cooler not like ac

    • Bijli Bachao Team

      Hi Gaurav,
      Your room requires a cooling of 1.7 tons during night time. So a 1.5 ton lloyd inverter AC should be able to make your room comfortable at night. That is it should be able to make the temperature around 24-25degree. If not then the AC may have some problem. If you plan to change AC we recommend you to go for a 2 ton inverter AC it will be able to cool your room during peak summer daytime also.

      You can look at these 2 ton inverter

      brand model eer_ratio price
      MITSUBISHI ELECTRIC MSY-GE24VA 3.61 NA;
      LLOYD LS24GRIX 3.6 58990
      LLOYD LS24GRI 3.6 58990
      HITACHI RAU023EUEA 3.56 58950
      HITACHI RAU024CVEA 3.55 67790
      HITACHI RAU024IVEA 3.55 64790
      HITACHI RAU024AVEA 3.55 62790
      HITACHI RAU023HVEA 3.5 61790
      CARRIER Octra Inverter (2.0T) 3.49 61750
      CARRIER Superia Plus K+ (2.0T) 3.46 60750
      CARRIER Kurve Inverter (2.0T) 3.38 55500

  • gaurav

    Hello sir. ..as told earlier I have purchased lloyd ls18gri. ..as temperature is 40 these days I have noticed that in night my ac is not performing well it is just cooling normally not making my room chilled running after 4 hrs. …now I m not satisfied. …should I sell this product in cheap and buy o general inverter ac. ..or this is problem with all inverter ac? ???please suggest

    • Bijli Bachao Team

      Hi Gaurav,
      How much chilled do you want your room? A 1.5 ton inverter would be able to provide a comfortable temperature of 24-25 degree. It should work well during night time. And if there are more floors above your room it should work relatively well during daytime also. If you want your room temperature to reach 16-17 degree and make your room super chilled than we recommend you to go for a 2 ton inverter AC.

  • Sandip

    Can you tell me whether the compressor ever stops in inverter ac? I have always seen it running at different speed but it never stops.

    • Bijli Bachao Team

      Compressor does stop in inverter AC is there is no heat coming in the room and temperature is almost maintained at the right level.

  • Audie Desa

    My hall AC is a Samsung 1,5 Ton 2 star. The hall is 18ft X 18ft ( 324 sq. ft). Is this AC good for the hall? I was told that I need to install an other AC 1.5 ton for this area, now that means I will be running two ACs at a time, now that is going to be pretty costly right? What I am thinking is if I do away with this Samsung 1.5 Ton 2star AC and install a 1.5 Ton O General (Inverter) AC will this help in any way? Do Inverter ACs come in stars (2 – 5). What will be the cost of a O General 1.5 Ton (Inverter) AC? Is this change over going to help me or will it be a waste of money?

    • Bijli Bachao Team

      Hi Audie,
      Assuming that there are more floors above your room, and your ceiling is not facing any direct sunlight. Your room would require a cooling of 2.3 tons during peak summer daytime. If your room is on the top floor you would require a cooling of 2.8 tons. For usage at night your room would require 2 tons of cooling.
      What is your usage of AC in hrs/yr? And is AC mostly used during night or daytime?
      You would have to go for a 2ton inverter AC or a BEE 5star 2 ton AC depending on your usage. Inverter ACs do not have star rating they are not rated by BEE. But inverter ACs are about 30% more energy efficient compared to a BEE 5star AC.

      You can look at these 2 ton inverter

      brand model eer_ratio price
      MITSUBISHI ELECTRIC MSY-GE24VA 3.61 NA;
      LLOYD LS24GRIX 3.6 58990
      LLOYD LS24GRI 3.6 58990
      HITACHI RAU023EUEA 3.56 58950
      HITACHI RAU024CVEA 3.55 67790
      HITACHI RAU024IVEA 3.55 64790
      HITACHI RAU024AVEA 3.55 62790
      HITACHI RAU023HVEA 3.5 61790
      CARRIER Octra Inverter (2.0T) 3.49 61750
      CARRIER Superia Plus K+ (2.0T) 3.46 60750
      CARRIER Kurve Inverter (2.0T) 3.38 55500

      You can look at these BEE 5 star 2 ton ACs

      brand model eer_ratio price
      CARRIER SUPERIA (2.0T) 3.64 50500
      HITACHI RAU524IUD 3.61 52400
      HITACHI RAU524HUD 3.61 59555
      MITSUBISHI ELECTRIC MS-GK24VA 3.57 51150
      HITACHI RAU524ITD 3.55 57000
      VOLTAS 2.0T 245 DY 3.55 42988
      BLUESTAR 5HW24MA 3.52 44133
      GENERAL ASGA24FTTA 3.51 54533

  • Sandip

    Hi, I have bought a 1 ton Bluestar Inverter ac for my 120 sqft room few days ago. I have noticed from the first day that when I set a certain temperature (say 28 deg) it sets 2 deg below it (26 deg). So to maintain 28 deg I have to set it at 30 deg always! I know that normal star rated ac power off its compressor when it reaches 2 deg below, but is it normal for an inverter ac?

    • Sandip

      and once it set the temperature 2 deg below, that temp is continuously maintained, so no problem in efficiency of the inverter.

    • Sandip

      Why don’t you reply??

    • Bijli Bachao Team

      Hi Sandip,

      We get a whole lot of comments every day. Responding to them within a day is extremely difficult. Sometime it takes 2-3 days to reply. So please bear with us.

    • Bijli Bachao Team

      Hi Sandip,

      Its a strange problem that you have. We have typically heard from people that they have to keep it less to maintain higher temperature as the thermostat is in the indoor unit and senses the temperature of air near it. So to maintain 26 people have to keep it at 25. Your case is exactly opposite. You must ask about this to Bluestar (and do let us know the answer you get from them).

  • pratap

    Hi I recently purchased Panasonic 1.5 TON CU-YC18RKYH3 MODEL AC.iTS BEEN 20 Days now.I dont have any major electrical items except fan tube lights. I run the AC at 25 degrees and I get a bill of only 60 rupees which says only 30 units were consumed.I run the ac the complete night and 10 hours during daytime on weekends.Is something wrong with my meter?

    • Bijli Bachao Team

      Hi Pratap,

      It certainly looks like there is some problem with your meter. Or you would have received an average reading on your bill.

  • Brajesh Pathak

    I have recently purchased IFB 1.5 Ton Split Ac. In my locality there was low (Between 185V to 120V) voltage issue and so I was suggested to buy Voltage steplizer by company Engg. Now I have purchase V guard 400 Steplaizer whose Input voitage range is between 90V to 280V. Even now my ac is having the same issue. After ac is switch on it compressor takes near about 10 min to start, after running for 20-30 min all of sudden it get tripped, after this it take more than 30 to 45 min to start again. Here I will like to mention that even after using steplizer there is no constant voltage supply. so I will like you to suggest me that what actually the problem is. Is the issue with Ac or with Steplizer.

    • Bijli Bachao Team

      Hello Mr Pathak,

      It looks like there is a problem with your stabilizer. You should call up VGuard and put a complaint regarding the same. We have seen that several people have complaints with stabilizer not performing when the voltage goes too low. Companies market that their stabilizers can upscale low voltages as low as 90V, but many a times these do not give output in AC’s working voltage range. You should ask VGuard as to why the stabilizer is not able to give output in working voltage range of AC when it is meant to stabilize voltage as low as 90 V.

  • Audie Desa

    One of my Acs has about 3/4 of a meter of its insulation eaten away by a rat and now the copper pipe is exposed and I also see that these exposed pipes sweat a lot when the AC is on. Will these exposed piping effect the cooling of my AC?

    • Bijli Bachao Team

      It will certainly effect cooling of the AC. Your refrigerant will loose some of its cooling capacity. You should get it covered properly.

  • Anant

    Hi, I found very helpful informations at this place. Thanks.
    I just bought three split ac of make IFB 1.5 T. I live in Nasik at ground floor with open at ceiling. The room sizes are 120 sq ft each. How much consumption of energy will be there if I use 2 hrs daily and 6 hrs night? The model is IACS18KA3TC.
    Thanks in advance.

    • Bijli Bachao Team

      The model has rated power consumption of 1605 watts. Assuming that it is right sized and compressor is on 80% of the time, its power consumption would be 1605*0.8/1000 = 1.284 units (or KWH) per hour. At night the compressor time would be less and let us assume it is 60% so unit consumption per hour would be 0.963. So each day your AC would be consuming about 8 units (for each AC).

    • Anant

      Hi. Thank you very much. The same calculations I did. But when I started using the ac, I found 3.5 units within an hr. I ran the ac for 2 to 3 hrs the units were about 9 plus. Is something wrong with my ac? I didn’t even started using simultaneously. One more thing: The outdoor unit is rated as 1605 watts. And indoor unit is rated as 1650. Pl help me. Should I return the ac to manufacturer?

    • Bijli Bachao Team

      The indoor unit is just the evaporator and fan which does not consume so much electricity. 1650 is for the outdoor unit only (which contains the compressor). 3.5 units in an hour is exceptionally high. It should not be that high. Something is wrong somewhere in the installation. You should get it checked.

  • K.Kumar

    My split AC indoor unit stops after 45 minutes running, the temp goes below set point of 25 deg c, then I had to switch of the whole unit, run the celling fan, after it reaches the room tem of 30 deg, if I start it works and run for 45 mts again it stops, Even if run the AC in Fan mode it runs only for 45 minutes, the Indoor Fan is not running continuously. pls confirm what could be the problem, how to rectify this.

    • Bijli Bachao Team

      Hello Mr Kumar,

      Some ACs have energy saver mode where it works for a few minutes and stops for a few minutes. But you have mentioned that it is also happening for you in Fan mode. It should not happen that way in Fan mode. Looks like there is some problem in your AC. You must call up the service desk of your manufacturer.

  • Jackson

    Appreciate your work, please review this model Godrej GSC12FB3WNT
    Thanks.

    • Bijli Bachao Team

      Hi Jackson,

      Godrej as a brand is a good Indian brand. They have good efficient ACs. However they have aluminium parallel flow condenser that can be difficult to maintain in harsh climates. However choice of a model should not just depend on a review but also on 1) Size of your room 2) You city 3) Your usage hours in a year. If you have high usage then this BEE 3 star rated AC would not be good for you.

    • Jackson

      alright well these are the details as you wanted
      1) 14 * 9
      2) Mumbai
      3) 1095 hrs

    • Bijli Bachao Team

      Hi Jackson,

      1 ton is the right size for your room in Mumbai, however your usage of AC is high. In Mumbai the tariff is as high as Rs 10 and in such case we recommend people to go for BEE 5 star rated or better inverter technology air conditioner with annual usage of 1000 hrs or more. BEE 3 star rated AC would not be ideal for your electricity bills.

  • jayant

    Does the fuel consumption of car depend on the fan speed of the air conditioner I.e if fan is at High speed will it consume more fuel,?

    • Bijli Bachao Team

      It will. Because more fan speed means more air circulation and more air circulation means almost every corner of the car will get cooled. And along with that more fan speed itself will have more power consumption. So certainly higher fan speed will result in consumption of more fuel.

  • Ankur

    Hello,
    You guys are doing a great job,so please accept my regards. Now I have a peculiar problem , I have been using a voltas 1.5 ton split ac for past 3 yrs. The unit has been working fine,but since last year even if I set the thermostat at 21deg.c , the compressor cuts off at 24 deg .c. Even if I set the thermostat further lower say 19 deg.c then also the compressor cuts off at 24 deg .c. I am running the ac in cool mode .Also this usually happens during night time, while in the day the unit does cool the room below 24 deg c and further down upto 22 deg.c .Now is the thermostat defective , or is the ac running in auto mode(some kind of forced auto mode though display shows cool mode ), or has it got to do something with external temp. I am in Delhi , guys kindly help is there some problem or am I just imagining one.

    • Bijli Bachao Team

      Hi Ankur,

      Your problem is indeed strange. If it was happening during day time, we would have thought that the Outdoor unit is getting direct sunlight and outside temperature is going beyond operating temperature of the AC. But it is quite strange that it is happening at night. Outdoor temperature does effect working of ODU but at night the temperature is not high outside. Would suggest you calling up Voltas and ask them to check it.

  • gaurav

    How is performance of Lloyd ls18gri ac of 1.5 ton. .Please review. …

    • Bijli Bachao Team

      Hi Gaurav,
      Lloyd ls18gri 1.5 ton AC has an EER of 3.2. which is decent. Lloyd is a great brand. So if you want you can also go for it.

      If you want you can also look at these more efficient 1.5 ton inverter ACs:

      brand model eer_ratio price
      HITACHI RAU019CVEA 3.81 56090
      HITACHI RAU019IVEA 3.81 53290
      HITACHI RAU019AVEA 3.81 51390
      DAIKIN FTKM50PRV16 3.8 49590
      HITACHI RAU019EUEA 3.8 50450
      HITACHI RAU018IUEA 3.73 57777
      SHARP AH-XP18PHT 3.66 43690
      SHARP AH-XP18PMT 3.66 49990
      SHARP AH-X18PET 3.66 41700
      SHARP AH-XP18MV 3.66 45500
      HITACHI RAU018HVEA 3.61 53960
      CARRIER Kurve Inverter (1.5T) 3.57 48488
      GENERAL ASGA18JCC 3.51 54500
      HITACHI RAU018HUEA 3.5 48900
      DAIKIN FTKP50PRV16 3.46 42850

    • gaurav

      Thanks for replying. ….is Lloyd ls18gri a inverter ac…..I m having a room size of 15×13 on first floor ..how much unit it will consume in night for 6 hours at 24 temperature. ..I m from lucknow

    • Bijli Bachao Team

      Hi Gaurav,
      Yes Lloyd ls18gri is an inverter AC. It will consume about 1.1 units/hr.So for 6hrs it will consume about 6.6 units.

    • gaurav

      Thanks for replying. …you guys are doing a great job. …Thanks for your advice. ….I have purchased lloyd ls18gri. ..it’s a very good ac. ..cooling is awesome. …is it a good deal I have done? ???

    • Bijli Bachao Team

      It is certainly a good deal.

  • Audie Desa

    I live in Mumbai. I have a Samsung Split AC 1.5Ton in the hall (2 Star). The area of the hall is 18ft x 18ft. I am on the first floor. The problem is, I am now running this AC at 28 deg. C. in the evenings only for about 2 to 3 hrs. and I have noticed that there is no water being thrown out of the indoor unit. I have checked the drain pipe it is clear. If the drain pipe was chocked then water should be falling in the hall, but I see no water driping in the hall. The compressor is cutting off and comming on and the cooling is also very good. What could the problem be? I am also running two other ACs in both the other bedrooms, their are also Samsung Split 1.5 Ton. I am also running these two at 28 deg. C. but for 5 to 6 hrs. at night but these two ACs throw out water. Is there any problem with my hall AC?

    • Bijli Bachao Team

      Hi Audie,

      Mumbai is quite humid and the AC should throw out water. And if it is cooling then it should be removing humidity. I guess the water is not going out through the right outlet. You should certainly get it checked.

  • anita

    Mine is a window AC Volta’s n its compressor work for 15 min than it comes to fanode why so n it happened just after getting it serviced

    • Bijli Bachao Team

      Hi Anita,

      There are few reasons for AC not cooling properly which we have listed on this link: https://www.bijlibachao.com/air-conditioners/possible-reasons-for-air-conditioner-not-cooling-properly.html … the main being direct sunlight on the AC from outside.

      However if it has started happening after servicing and it had worked in the same place before. You should check with the person who has serviced it.

  • Srimanth

    Hi Abhishek,

    I appreciate the amount of information that you have been sharing to the people. I sense that you mostly focus on saving the electricity which is a great initiative and I admire it so much. I am from Hyderabad.

    I to have a simple question. I just bought Daikin FTKP50PRV16 Inverter model 1.5 ton AC. My room temperature was about 31 degrees centigrade and when I put my temperature to 22 degress centigrade. I almost kept it running in COOL mode for about 15mins and the temperature reduction was only to 29 degrees centigrade. But I felt little amount of chillness when I entered the room for even 29 degrees centigrade. I checked that room temperature from on unit’s remote controller. So my question is, how much of average time does an AC take to cool the room by an average of 8 degrees centigrade (i.e. in this case from 31 – 24 degrees centigrade).

    Thanks in advance.
    Srimanth.

    • Bijli Bachao Team

      Hi Srimanth,

      What will be the size of your room? Also it is top floor or lower floor?

    • http://google+ Srimanth

      room size is 165 sq.ft. My flat is in second floor. There are 3 more floors on top of mine.

      Thanks,
      Srimanth.

    • Bijli Bachao Team

      Hi Srimanth,

      Typically tonnage calculation is done in such a way that AC should at least be able to bring down the temperature to about 24-25 (which is the most comfortable temperature). For 165 sq ft room as per our approximate calculation for Hyderabad, the tonnage requirement is 1.4 or 16800 BTU/hr. Now this is assuming the outside temperature is 41-42 (about peak temperature). Now this is requirement to reduce temperature by 17 degrees. If we take these numbers and assume that the 1.5 ton AC is cooling at marketing capacity of 1.5 ton or 18000 BTU/hr then it to reduce 8 degrees it should take about roughly 26-30 mins. However this is all approximate calculation. Because as the temperature decreases, the time taken to decrease the temperature increases. I personally have a 0.75 ton inverter AC for a 120 sq ft room in Mumbai. It’s just aptly sized. When I did measurements, it cools to 28-27 quite quickly (within an hour), however to reach to 24 it took 3-4 hours. But still at 27 the room is quite comfortable. It took 9 hours to reach to 22. But then it was super cold. At night it cools much faster, this calculation was done during the day when outside temperature was 31. Now my calculations were for rightly sized (in fact slight undersized AC). However in your case the AC is slightly bigger than the requirement. So it should cool faster.

    • http://google+ Srimanth

      Thanks So much Abhishek. Your calculation and explanation is pretty much the same with performance of my AC too. Appreciate your efforts mate.

  • khalid sayed

    Hi,
    I live in mumbai, my bedroom size is 135sqft. My room is on top floor i have also done false cealing of pop boards which is filled with 1 inch of thermacole sheets and one side of my wall is towards east. After showing my room to several ac technician’s they recommended me to buy 1.5 ton ac though the usage is only at night.

    So i have brought a window airconditioner of Hitachi 1.5 ton 3 star model RAW318KUD. Do the ac is oversized or sufficient, after visiting your site bijli bacho an looking at various model’s mentioned to save energy. You have given this model no 1 for saving energy. I have read all the question & answers given below i have a question if i run the ac which i use it only at night at 27 degrees will the compressor get defective or it will save energy. Beacuse i have asked the companys mechanic he told me if i use below 25 energy will not be saved, if i use above 25 then also energy will not be seved after hearing this i am confused what should i do i am comfortable with 27 degrees but after reading in the question answers below that if used at low temperatures it will affect the compressor. Please reply.

    • Bijli Bachao Team

      Hi Khalid,
      According to our calculation your room requires a cooling of 1 tons. So a 1.5 ton AC is oversized for your room. So it will consume unnecessary electricity. We recommend you to go keep the temperature at 27 degree and use power saver for your AC to save power.

  • Nitin Saxena

    Hi team,

    I am using Videocon vs5j we2 1.5 ton 3,star split ac frm last 1 year. Watt consumption is 1680, cooling cap 5200,sqft, I live in Agra nd room size is 11*12 ground floor don’t reflects direct sunlight, outdoor unit has installed on Frist floor roof, after 2pm to 6 pm in hot summers direct sunlight reflects on outdoor unit, pls suggest which mode nd temp is suitable for minimum power consumption usage, plz calculate 3 hr consumption in day nd in night usage 6 hrs. Temperature reaches in may June at 46 c.

    Secondly, I am planning to purchase new split ac for my second floor room sized 11*22, which reflects side face sunlight between 1 pm to 6 pm, I hav 2 floors in my home, plz suggest the right one air conditioner with 5 start ratings for minimum power consumption. My budget for 2nd ac is 40 k.
    Regards
    Nitin saxena
    Agra

    • Bijli Bachao Team

      Hi Nitin,
      Videocon vs5j we2 1.5 ton 3,star split ac would consume about 1.4 units per/hr. So for 9 hrs of usage it would consume about 12.6 units/hr. To save power we recommend you to keep the AC in sleep mode.

      Your room at second floor would require at least 2.8 tons of cooling. So you would get only a BEE 5star 1.5 ton AC in your budget. So we recommend you to keep the AC close to your bed it will provide you local cooling near that area.

      You can look at these BEE 5star 1.5 ton ACs around 40k:

      brand model eer_ratio price
      HITACHI RAU518HUDD 3.64 38600
      LG LSA5VP5D 3.6 35977
      DAIKIN FTF50PRV16+RF50PRV16 3.6 38733
      LLOYD LS19A5SN 3.55 32877
      PANASONIC CS-KC18PKY-1/CU-KC18PKY-1 3.53 32800
      LLOYD LS19A5LN 3.52 32212
      VOLTAS 1.5T 185 CY 3.51 32450
      VOLTAS 1.5T 185 EYS N 3.51 34888

  • http://elib.in Himanshu

    Can i use 1.5 ton 5 star samsung ac with cooling capacity 5400 in my hall of 14*17 at 30 degree. which have 3 side covered and one side open. I am confused because 1.5 ton 5 star have cooling capacity 5400 and 2 ton 3 star have 6200.

    • Bijli Bachao Team

      Hi Himanshu,

      Your hall would need 7500-8000 watts of cooling capacity during peak summer day time. Anything less than that would not cool the whole room during peak summer day time. However peak requirement is only for a few days. At evening and night the requirement is less so a 6200 watts unit should be good enough for most of your requirement (during evenings and night). Also if you keep temperature at 30 then it may even work well during the day time in peak summer. But will certainly fall short if you keep temperature lower than 25.

  • http://elib.in Himanshu

    Can i use 1.5 ton 5 star samsung ac with cooling capacity 5400 in my hall of 14*17 which have 3 side covered and one side open. I am confused because 1.5 ton 5 star have cooling capacity 5400 and 2 ton 3 star have 6200.
    So can i use 1.5 ton 5 star ac at 30 degree in my hall.

    • Bijli Bachao Team

      Hi Himanshu,
      Which city do you live in? And is your hall on top floor with direct sunlight falling on the ceiling, or is it at a lower floor? And what will be your usage of AC in hrs/day and months/yr?

    • http://elib.in Himanshu

      I live in raipur, and just brought 2 ton 3 star samsung ac for my hall of 14 X 17.5 . i want to run ac during evening and night

    • Bijli Bachao Team

      Hi Himanshu,

      Your hall would need 7500-8000 watts of cooling capacity during peak summer day time. Anything less than that would not cool the whole room during peak summer day time. However peak requirement is only for a few days. At evening and night the requirement is less so a 6200 watts unit should be good enough for most of your requirement (during evenings and night). Also if you keep temperature at 30 then it may even work well during the day time in peak summer. But will certainly fall short if you keep temperature lower than 25.

  • https://plus.google.com/106970113402444211894 Ishan Attri

    Kindly suggest me which AC is best suited for me along with star rating. Room Size-13*11feet, first floor(4 stories building), usage 8-10 hours, Location Delhi, Direct sunlight in the morning for 2-3 hours.

    • Bijli Bachao Team

      Hi Ishan,
      According to our calculation your room requires 1.3 tons of cooling. So for your usage we would recommend you to go for 1.1/1.2 ton inverter AC.

      You can look at these 1.1/1.2 ton inverter ACs.

      Brand Model EER Ratio (Cooling) Tonnage Price
      Hitachi RAU014CVEA 4 1.2 54690
      Hitachi RAU014IVEA 4 1.2 51690
      Hitachi RAU014AVEA 4 1.2 49690
      Sharp AH-XP13PHT 3.83 1.1 NA
      Sharp AH-XP13PMT 3.83 1.1 37896
      Sharp AH-X13PET 3.83 1.1 32346
      SHARP AH-XP13LV 3.83 1.1 31700

  • RAMESH

    Sir I live in delhi . I am comfortable when I use AC at 32-30 °C . my friend said if I use AC at this temperature AC compressor will not last long life and it would effect the AC functioning . He suggested to use it at 25°C. Is it true. I want to save electricity. Please suggest

    • Bijli Bachao Team

      Well the compressor cycle (running time) depends on the temperature difference between outside and inside the room. If the temperature difference is less (as in your case) the compressor will have short cycles. Which would certainly save electricity as compressor will run for a short time. However when compressor runs in short cycles (due to oversizing) it is not able to obtain optimum efficiency. Because efficiency of compressor is less during starting as well as stopping. And optimum cycle time is about 9 mins (from start to stop of compressor).

      Most oversized AC have short cycling and most ACs purchased in India are oversized. This does not mean that ACs have a short life. However that is certainly not running in efficient manner. Now in your case if you plan to run at 32-30 then the best thing would be to undersize the AC. So if your room needs 1.5 tons cooling during peak summer. Best thing is to go for a smaller 1 ton AC. Because you do not want to cool the room a lot. And a 1 ton AC would bring down the temp to 32-30 (however may not be able to bring temperature down to 20)

    • Sandip

      Is this optimum cycle of 9 min applicable for inverter ac also? As the compressor always runs in variable wattage.

    • Bijli Bachao Team

      Not really as the compressor is on all the time.

  • Siddharth

    Hi
    I am planning to buy a split AC for my room which has a size of 12X10. I am assuming that at this room size 1 ton would have normally sufficed. However the room has two doors, one large and one small window, it is on the First Floor with a terrace on top of it (hence direct sunlight on the ceiling). I live in Kota and it gets pretty hot here (42-43 already). Now other than the room size I dont know how to take these other factors into consideration. Kindly recommend whether I should go for 1 ton or 1.5 ton? I want to ensure sufficient cooling but also dont think it would be wise to waste electricity by deploying a 1.5 ton if 1 ton can do the job. Budget is not really a constraint.

    • Bijli Bachao Team

      Hi Siddharth,
      According to our calculation your room requires 1.4 tons of cooling during peak summer daytime. So if your usage is mostly at day you should go for 1.5 ton AC. At night time your room would require 1.1 tons of cooling. So if your usage is only at night you can go for a 1 ton AC. If budget is not a constraint we recommend you to go for a 1.5 ton inverter as it will save about 30% electricity compared to A bee 5star AC and also it will automatically adjust itself according to the tonnage required for your room.

      You can also look at these most efficient 1.5 ton inverter ACs:

      Brand Model EER Ratio (Cooling) Price
      Samsung AR18HV5DAWK 3.82 53500
      Hitachi RAU019IVEA 3.81 53290
      Hitachi RAU019AVEA 3.81 51390
      Daikin FTKM50PRV16 3.8 49590
      Hitachi RAU019EUEA 3.8 50450
      Sharp AH-XP18PHT 3.66 43690
      Sharp AH-XP18PMT 3.66 49990
      Sharp AH-X18PET 3.66 41700
      SHARP AH-XP18MV 3.66 45500
      Hitachi RAU018HVEA 3.61 53960
      Carrier Kurve Inverter (1.5T) 3.57 43900
      Samsung AR18HV5NFWK 3.55 43500
      O General ASGA18JCC 3.51 54500
      Hitachi RAU018HUEA 3.5 48900
      Daikin FTKP50PRV16 3.46 42850

  • SHANAWAZ

    What will happen if I put split AC on 31°c

    • Bijli Bachao Team

      Will depend on outside temperature. If outside temperature is 31 or less then compressor will not run at all (as no cooling is required). However if it is more then there will be heat flow in the room and compressor will have to work to remove heat. The amount of work it has to do (or electricity consumed) will depend on the temperature difference.

  • vamshi

    hello

    i am planning to buy an A.C for my room

    room- 12*10 sq feet, second floor, hyderabad.

    recommend the tonnage and a list of possible choices of A.C’S

    • Bijli Bachao Team

      Hi Vamshi,
      Is second floor top floor with direct sunlight falling on the ceiling,or is it lower floor? What will be your usage of AC in hrs/yr? And what is your budget? (This is important to calculate the tonnage and the right model of AC for your room)

    • vamshi

      building has totally 6 floors ,ours is 2nd floor.
      usage will be at maximum 7-8 hours in summer and will be very low in winter.
      budget is below 45k

    • vamshi

      and the area of the room is 14*12 sq feet not the one mentioned in my first post

    • Bijli Bachao Team

      Hi Vamshi,
      According to our calculation your room requires a cooling of 1.5 tons. So based on your usage we recommend you to go for a BEE 5star AC. If you want you can also go for an inverter AC. It is about 30% more energy efficient compared to a BEE 5star AC.

      You can look at these BEE 5star 1.5 ton AC:

      brand model eer_ratio price
      HITACHI RAU518EUDA 3.8 44450
      HITACHI RAU518HUD 3.8 41500
      HITACHI RAU518ITD 3.56 43100
      LLOYD LS19A5SN 3.55 32877
      PANASONIC CS-KC18PKY-1/CU-KC18PKY-1 3.53 32800
      LLOYD LS19A5LN 3.52 32212

      You can look at these 1.5 ton inverter ACs within 45k:

      brand model eer_ratio price
      SHARP AH-XP18PHT 3.66 43690
      SHARP AH-X18PET 3.66 41700
      SHARP AH-XP18MV 3.66 45500
      SAMSUNG AR18HV5NFWK 3.55 43500
      DAIKIN FTKP50PRV16 3.46 42850

  • sandip

    Hi,

    I have bought a Carrier AC 1.5T inverter.My room size is 145 sqft, staying in mumbai city, it’s in 3rd floor and no floor above this.my usage is 6-8 hr at night.
    i am little confused whether i have bought oversize ac. I usually try to keep 24 to 25 temp and turn-off after 6 hrs. please suggest how do i run this ac to save the electricity.

    • Bijli Bachao Team

      With inverter ACs oversizing is not a big problem. It will adjust its tonnage as per the need of your room. It should save electricity.

  • iftekhar

    i am using llyod 5 star split ac..living in top floor of appartment. setting ac to 28 and keep the fan running will consume more or less.. pl suggest
    and also pl tell me, ceiling fan kept at high speed will consume more when compared to low speed?

    • Bijli Bachao Team

      Hello Mr Iftekhar,

      Ceiling fans induce a draft of air which when circulates around our bodies make us feel cooler (because of the sweat that comes out of our body). When used along with AC, it can help us increase the temperature setting in the thermostat of the AC. Increasing the temperature reduces electricity consumption significantly. However when you have a hot ceiling, using a ceiling fan will move the hot air on top towards bottom, and this can increase the electricity consumed by AC. So if you live on top floor, using a ceiling fan would not help. Instead you should use a table fan or pedestal fan with AC rather than a ceiling fan.

      A fan consume more electricity at high speed as compared to low speed.

  • Tushar Naik

    How can fan automatically stop in LG spilt Ac

    • Bijli Bachao Team

      It should not. If it does then you should call up and lodge a complaint with LG.

  • a v somesh

    i baught a split ac 1.5T. we are using this in night time 4 to 5 hours in 28 degrees set point. next day if we can check metre reading, 10 units consumed. actually how many units will take for 4 to 5 hours of using AC. whats the reason? can u give any suggestion?

    • Bijli Bachao Team

      Hi Somesh,
      Which model AC have you installed?

  • Ankit

    HI,
    I have purchased Voltas 1.5 ton 2 star AC, i live in Lucknow, Ground floor with open terrace and three sides cover, i dont get direct sunlight in my room. my room size is 13×16. how much time will my AC take to cool my room.

    • Bijli Bachao Team

      Hi Ankit,
      According to our calculation your room requires 2 tons of cooling. So a 1.5 ton AC is undersized for your room and it will take about 45 mins to cool the room to a comfortable level.

  • wina

    Hi im wina, i want to ask you, if i set low temperature at my remote for example 16 or 17°c my unit will follow but suddenly it came back to 37°c and my room is looks like having a heater than an air conditioner. What should i do? Do u think thay my AC is broken?

    • Bijli Bachao Team

      HI Wina,

      It certainly looks like your AC is broken. You should contact the manufacturer’s customer support for the same.

  • S Taparia

    Dear Abhishek,

    Thanks for the nice article.

    I noticed that in my 1.5 Ton AC ( Samsung) which is 5 years old unit, we set the temperature to 24 but after some running it automatically started showing higher temperature on the display i.e. the displayed numbers were increasing from the temperature initially set by us e.g. 25..26..27 ..28 …This is not happening immediately after starting the unit.

    Just wanted to know what could be reason ? Would this need attention of a mechanic.

    Thanks
    S Taparia

    • Abhishek Jain

      Well at times some ACs have energy saver or sleep mode which reduces the temperature with time. Which mode are you running your AC on? Is it cool mode?

    • S Taparia

      We are not running in energy saver or sleep mode. It is normal in cool mode. In fact, sometimes, immediately after starting the unit, it goes to 30 which is highest possible temperature. I tried switching it off but when switched on again – it went to 30 and it does not allow me to reduce it below 30.

      People who came for regular servicing also could not figure out exact problem.

    • Bijli Bachao Team

      Looks like a problem with the air conditioner. Would recommend lodging a complaint with Samsung.

  • Ameya

    I usually plan to on ac at night use for initial 2 hrs and switch off rest of night and let ceiling fan run.. Is it OK to keep lower temperature in such case like 22 or I’ll run only at 24-25. Or you suggest ac to be on overnight at 24-25

    • Abhishek Jain

      Running AC for 2 hours will be more electricity saving as compared to running AC for 8 hours. If you are comfortable with switching off after 2 hours then you should continue with that.

    • Ameya

      what about temp.. if i maintain 24 then wil my room get heated quickly as compared to 22? or there wont be much

    • Bijli Bachao Team

      Hi Ameya,

      ACs have a standard cooling capacity which means they can remove heat from a room at a fixed rate. So even if you set it to 22 and your room’s temperature is 34 while coming down from 34 to 22 …. it has to cross 24 :) …. so it will always reach 24 before it reaches 22.

  • Krunal

    Hey,
    I have installed 1.5 ton A.c . Its working very well . The thing is even if i keep the temperature at 28degrees,it gets very cold and i have to use a blanket. Room size is 12x15sqft. Is there any problem wth compressor or temp sensor ? Also the auto cut off and start time is very short. It shuts and start again very three minutes when temp is set at 26degree.
    Thank you.

    • Abhishek Jain

      Hi Krunal,

      Which city are you in? Also which floor are you on (top floor with sunlight on ceiling or lower floor with more floors on top)? An oversized AC can overcool the room. And not just over cool but consume more electricity as well. Short cycle can also lead to bad humidity removal and can lead to bad smell from AC in future.

    • krunal

      Hi Abhishek, Thanks for prompt reply. I am from mumbai. I stay on 17th floor. Just one floor above me. Do you think there problem with compressor or temp sensor?

    • Abhishek Jain

      Hi Krunal,

      As per my calculation you need about 1.3 tons of cooling for your room. However as you are on 17th floor the temperature at that height in general will be lower even during summers. So may be that would reduce the tonnage requirement to 1.2 ton during peak summer day time. However this requirement is during peak summer day time. During night time the heat is much lesser and thus night time requirement is lesser. Would suggest you to go for an AC power saver as described on this link: https://www.bijlibachao.com/air-conditioners/power-saver-devices-for-air-conditioners.html ….. this company sells the same in Mumbai: http://www.omenergysavers.in/

  • Prasanth KR

    Which is the best option for Air conditioner- Swing or Fan?

    • Abhishek Jain

      Both serve different purpose. Swing helps in throwing the air in all directions. Fan blows the air. If you are seated at one place, you can off the swing. Keeping fan speed low will decrease electricity consumption but you do not feel cool enough when you don’t get air. So if you use ceiling fan then you can keep AC fan speed low. But if you do not use ceiling fan, keeping fan speed to high is better.

  • Vivek Thaker

    Hi Abhishek,

    I am living in 2BHK tenement at Rajkot city, Gujarat where pick summer temperature is 45c. I am going to purchase two split ac for bedrooms further detail of my bedrooms and query here bellow.

    # Bedroom 1: Size 8? X 9?, Ground floor with open terrace and three sides cover, 15sq ft. window in west no direct sunlight on window.

    Occupancy: Single person

    Usage: 2Hrs. Day time and 4-5Hrs. at night

    #Bedroom 2: Size 8? X 11?, First floor with open terrace and three sides cover, 10sq. ft. window in east balcony no direct sunlight on window.

    Occupancy: 2 Adults and 1 Child

    Usage: 7 to 8 Hrs. Night use only

    Query

    1. Does 0.75 or 0.80Ton ac is ok for bedroom 1.
    2. 3 Star, 5 Star or Inverter, Which ac is more efficient for my usage.
    3. Please suggest few options with model no.

    Do take your time.

    Thanks.
    Vivek Thaker
    [email protected]

    • Abhishek Jain

      Hello Mr Thaker,

      How many months in a year do you use the AC?

  • shyam

    Hi Abhishek,

    I am living in Delhi, bought Hitachi RAW KUD 1.5 ton 3star window Ac in the beginning of May 2014 to fix into my room which is located on the top floor(3rd floor) of the building having 1 sun facing wall , i was quite satisfy with the performance of my AC during the extreme session of May & June despite consuming more electricity…..12-14 units per night ..

    just 3.5 months over and we are sitting in month of August, where the average temperature of Delhi is 30 to 31 degree, sudden i have noticed a change into the performance of my AC, now it takes too much time to spread the chilling into the room, some time its compressor takes more than 1 hour to cut off … though i have set the temperature on 25 Degree…..

    please advise …

    regards
    Shyam

    • Abhishek Jain

      Hi Shyam,

      It sounds like manufacturing defect. It should not happen this way. You should call up Hitachi and register a complaint for this.

    • Charanpreet

      Hi Shyam,

      In Delhi month of August is very humid as compared to May and June, And High Humidity effects the air conditioning very badly. As during dehumidification, water vapors present in air releases the Latent heat and changes to liquid form. This Latent heat again increases the air temperature. So in humid environment compressor of air conditioner will be working much much more for decreasing the temperature by same range, than it was working earlier when it was less humid.

  • Jamey

    What differences does location of thermostat have on energy consumption? More directly mine is in the corner of a short hallway.

    • Abhishek Jain

      Hi Jamey,

      Thermostat should be located away from direct sunlight/windows. It should be on the interior wall and it should be located where natural room air currents?warm air rising, cool air sinking?occur. There should be no furniture around it that blocks movement of air around it.

    • Jamey

      I am thinking of moving the thermostat out of the hallway into the family room wall next to the hallway. It’s the biggest room, no corners. As it is now the return is sitting right under the thermostat; if I move it I think the return could still move air past it coming from the family room which is centralized in the house. Good idea?

    • Abhishek Jain

      Hi Jamey,

      I am not able to visualize properly. However as long as the thermostat is not covered and it gets to sense the room temperature properly, keeping it in the family room will be better as it will work according to the temperature in the family room.

  • Josepha

    what is usually the temperature of the air emitted from the AC? as i am suspecting the the air coming out of the wall unit is not cool as it should be. thanks

    • Abhishek Jain

      Hi Josepha,

      It will depend on the cooling capacity of the air conditioner. Cooling Capacity is the rate at which the AC can remove heat from air. If this rate is more than the rate at which the air gains heat from outside, then the AC can reduce the temperature of air as much as you want it to (that is what the thermostat controls).

      Hope this helps.

    • Abhishek Jain

      If you feel that the air coming out of your AC is not cool enough, then it means that its cooling capacity has reduced and the rate at which it is removing heat from the room is lesser than the rate at which the air in the room is gaining heat.

  • Anumakonda Jagadeesh

    Excellent. Yes. Air conditioning consumes much of power mostly in Cities. According to one study in Mumbai out of 2700 MW Consumption Air conditioning share is 1000 MW !
    Dr.A.Jagadeesh Nellore(AP),India

  • Karyn M. Bruce

    My husband keeps changing the thermostat all day long. When we go out, he sets the thermostat at a higher temperature (from 76 to 80). When we come home, it goes back down. When he go to sleep, it goes up. When I get too hot, I change it to make it cooler in the house. When he sees that, he sets it higher again. I believe that this constant change in A/C temperature affects the electric bill. Does it?

    • Abhishek Jain

      Hi Karyn,

      It will depend on the temperature outside. In winters if you keep temperature high, then heating will take a lot of electricity. In summers if you keep temperature low, then cooling will take a lot of electricity. Frequent change does not impact electricity bills, but the temperature difference between the room and the outside does.

  • Usman

    Hi. I have two rooms.One is of 160square foot and the other 170 square foot. I am currently using a 1 ton A.c.I have installed a ventilating fan 250mm in the wall between the rooms which transfers cold air from one room to another. The thing is that the other room’s temperature becomes moderate, better than outside temperature but it does not cool.There is still a marked difference in temperature between the room containing the A.c and the one being controlled by the fan. I wanted to know if shifting to a 1.5 ton A.C would increase the cooling in the room controlled by the ventilating fan ?

    Kindly let me know.
    Thank you.

    • Abhishek Jain

      Hello Mr Usman,

      AC works very differently from an air cooler. Cooler takes air from outside, cools it and throws it inside. Whereas working of AC is very different. It does not take any air from outside, in fact it takes inside air, cools it and sends it back. The tonnage or cooling capacity of AC depends on the total amount of air inside a room. If the room is small you need smaller capacity, if room is big, you need bigger capacity. And that is also why it is always recommended to keep the doors and windows of the room closed while using AC because any amount of extra hot air from outside will increase the load on AC which will either result in extra electricity consumption and/or in inadequate cooling.

      The sizing is done not just based on size of the room but also on several other factors like: number of people, number of appliances in the room, etc as everything adds to heat in the room. It also depends on city where you live in as some cities are hot and some are cooler. Now 1 ton AC is small for 160 sq ft room even in cities like Mumbai where temperature is not high but humidity is high. And what you are trying to cool is 160+170=330 sq ft. And 1 ton AC will never ever cool 330 sq ft space. Even 1.5 ton AC would not work.

      The most ideal setup would be to have individual AC in each room for their individual size.

    • Usman

      Hey Abhishek,
      Thanks for your reply.
      I have installed 1.5 ton A.c . Its working very well . The thing is even if i keep the temperature at 28degrees,it gets very cold and i have to use a blanket.I want to know should I switch to a 1 ton A.c since I dont think a 1.5 ton A.C would be used to its full capacity. And whether a one ton A.c would be a cheaper option bill wise? I am using the 1.5 ton A.c at a higher temperature fluctuating between 26 to 30 degrees.
      The room dimensions are the same.160sq foot and a 170 square foot room linked together by a ventilating fan in between them.
      Thank you.

    • Abhishek Jain

      One ton AC will certainly use lesser electricity as compared to 1.5 ton AC. It will also not cool as much as what a 1.5 ton AC does.

  • JACKSON KOMBAN

    hello Abhishek… appreciate your article.. I own 1 ton Godrej *** AC, by reading your article i keep temp @ 25 nowadays i wanted to know about the ideal mode and fan speed… the AC is installed in my bedroom say a standard family bedroom.the different modes are FEEL COOL DRY FAN & HEAT we often keep it in COOL MODE. the different fan speeds are AUTO HIGH MID LOW we often keep it in AUTO. are these ideal settings or should i change them. what you suggest ?

    • Abhishek Jain

      Hi,

      It truly depends on what keeps you comfortable. You should certainly derive the convenience that you need from your AC. 24-25 degrees is a good setting to keep. If you can keep it higher than that without being uncomfortable, nothing like it. Also looking at the number and kind of modes in your AC, it is better to keep it in cool mode. Dry mode would be good if you have high humidity. Also same for fan, if you are comfortable with low fan speed, then you can use that, however low fan speed will not circulate the air much, and if you are using a ceiling fan, then it would be good (as you can reduce AC fan speed as well as can increase AC temperature which can reduce your electricity bills).

  • Buddhika

    can save energy by reduce air conditioner capacity for same heat load?

    • Abhishek Jain

      it can certainly save energy if lower capacity can cool the room.

  • prabu

    Thanks Abhishek for good article. Im living in chennai. My room is around 12X10sqft and located in first floor, direct sun light on roof and one side of wall, Im using 1ton LG split AC. Usually I used it during night time only, normally temperature will be around 34 – 38 deg. I have switched off swing mode in AC and have allowed to flow air in single direction directly to me. I always keep temp in 29 or 30 with energy saving mode enabled and fan speed is below normal. Is this good for power saving and AC? Whether I need to keep AC in swing mode, also I need to decrease temperature? What about fan speed? Please advice to save power and which is good practice for AC.

    Thanks in advance,
    Prabu

    • Abhishek Jain

      Hi Prabu,

      First thing that is important is your comfort. You should derive the comfort you need from the AC. 24-25 is good for body’s thermal comfort. If you are comfortable at 29-30 then that is certainly better for saving electricity. Certainly if the flow of air is directly towards you, then you will feel more comfortable. If you put it in swing mode then the air will not flow in your direction and you may not feel that comfortable. Even for fan speed: the electricity consumption is higher at higher speed and lower at lower speed. But your comfort is primary. Else AC will not solve its purpose. So I think whatever you are doing now is good enough. Additionally what you can do is get a reflective white paint applied on the roof top or get something like XPS (Extruded polystyrene) board put on ceiling. This will reduce the heat in your room. Try to put some sun film on windows that do not reduce light but reduce heat. You may also use thermal insulating wall paper. Do check our section on insulation: https://www.bijlibachao.com/save-electricity/insulation

    • prabu

      Abhishek,

      Thanks for your valuable feedback.

      Prabu

  • Khaled

    Thanks Abhishek for the nice write-up. My question is related to savings when the AC is in heating mode not cooling mode. Does the equation above work. If for example outside is 12C and temp is 24, now I set it to 20, the savings will be around 41%?

    • Abhishek Jain

      It should work in heating mode as well. However the savings will be (4/12)*100 or ((24-20)/(24-12))*100 so about 33%.

  • ravi s

    In my office i am comforatble ac temp is 28 degree, but some told that if i put 28 degree ac may damage since comprosser will work minimum. it is correct. And sugest me 28 degrees ideal degree.

    • Abhishek Jain

      The compressor will have lower life if there is frequent switch on and switch off. And that will happen when you keep it too cold. So there should be no problem at 28. If you are comfortable with your AC temperature at 28, then it is the best. Below 24 should be avoided.

  • MEENA

    Hi Abhishek

    i have bought LLOYD LS13A5LN AC 1 TONE 5 STAR , BUT its fan is not running at low fan speed .Please advice me there is problem in AC. it is just 2 day before installed. what you suggest , ? i should go for replacement ? tell me more thing to check, so i come to know its working properly or not.

    regards

    meena sharma

    • Abhishek Jain

      You should contact Llyod customer support and ask for inspection and replacement. Its fan should have options to run at high, medium and low speeds. It certainly looks like a problem. Does it not have option to run at low speed or it does but it is not changing to it?

  • deep

    Is case if air conditioner is off but it’s switch remains in.so does the electricity bill comes

    • Abhishek Jain

      in some cases yes. Old ACs had 4-5 watts of standby power consumption. New ACs are much better (especially the split ACs). But yes it does consume electricity if switch is not off.

  • Madan

    Hi Abhishek
    Nice article i have 0.75 Ton blue star ac, my room is 10×10 feet in second floor. My problem is whether i set any temperature, ac come to room temperatur then decreases temperature but never reach to my setting in remote . Is there anything wrong with ac or it is not sufficient for room. I am
    Iiving in new delhi.

    • Abhishek Jain

      You need 1 ton AC if your room does not get direct sunlight on walls or ceiling. If you do get sunlight then it would need 1.2 ton.

  • Mohit

    Sir does split ac bring air from external environment ?
    If we keep room close will it suffocate?
    I have a voltas 1.25 ton ac.

    • Abhishek Jain

      It does not bring air from outside. However if you keep the room closed, you will not suffocate.

  • Sanjay Chandelia

    Hi, I have gone through most of your articles and they have been a deciding factor in purchase of my AC. Initially i had shortlisted Godrej 1.5T, 5 star AC but after reading your articles i went for Sharp AX-XP13PHT 1.1 Ton Invertor AC.

    My question is whether i will be able to recover my spendings. I live at Delhi, my room size is 9X12, height about 10Feet, middle floor, no direct sunlight, I run this at around 26-27 C.

    What would be the per hour unit consumption?

    Thanx and Regards.

    • Abhishek Jain

      As per my calculations, you need 1 ton AC for your room or 0.75 ton inverter AC. Even 1.1 ton inverter AC would work good. Electricity consumption should be about 0.6 to 0.7 units per hour max.

  • arunkumar

    If we turn on Air conditioner compressor will (on) immediately or it will take some time (seconds or minutes). which one is correct? Please suggest.

  • sanjay singhal

    Dear Sir,

    now a days, i am feeling less cooling from My window AC (1.5 T, Hitachi) in comparison to when it was new. How can i check the system is healthy.

    • Abhishek Jain

      How old is your AC? There is a concept of derating and with time the ACs derate and their cooling capacity decreases. But should not be a lot.

    • sanjay singhal

      Sir,
      my AC is 4 year old. could we check appropriate gas level in window AC, so that technician could not make fool us.

    • Abhishek Jain

      I am not aware of any easy way to do that.

  • tarun

    As u said ac will set 25 degree in less time than 18 degree its ok.and compressor stop, But as soon room temperature increases for say 26 degree or to 19 degree. Compressor starts it will take both same time to reduce 1 degree temp. So it vill consume same time same power.

    • Abhishek Jain

      It should consume same power and same time to reduce 1 degree temperature. However the room will get from 18 to 19 faster and it will be slow in going from 25 to 26. As the heat flow rate will be directly proportional to the difference between outside and inside temperature. So the compressor cycle will be more frequent at setting of 18 than at 25. So in a longer duration, power consumption will be more at 18 degrees.

  • nida subhan

    Hii abhishek,
    Mai jan na chahti ho ki agar compressior per pani gir jae ya zyada garmi ho to hum pani daal sakte hain ac mai koi probblam to nahi hogi

    • Abhishek Jain

      problem ?? ???? ???? ?????. infact ??? AC ?? ?? ??? ???? ????? ?? ?? ???? ???? ????? ????? , ???? AC ????? ???? ??. ???? ?? ????? ?? ????? ??? AC ?? ???? ????? ??.

  • Suresh

    I brought Samsung split AC 1 ton 4 years before since now i never seen my AC temp reduced less than 26 after running continue 9 to 10 hrs, most of the time it will touch the Temp max 28 after running 4-5 hrs.
    1. My room temp will be 34 -35
    2. My ODU is kept directly face to sunlight
    3. The ODU and IN-DU is just attached by the same wall, but inside and outside
    4. What mode has to be kept in summer season

    What should i do get a cooling air?

    Thanks,
    Suresh

    • Abhishek Jain

      Which city are you located in and what is the size of your room? From your response it seems one of the wall is directly facing the sun, does the roof also exposed to sun or do you have more floors above the room?

    • Suresh

      Abhishek, First thanks for your reply. I am from chennai, we stay in first floor there is no building above and side. My room window and door is fully enclosed with glass not wooden door so the sunlight directly fall to my room. size of my bedroom is small coarsely i can say 12×15. considering my room size i brought 1ton.

  • tapan

    Sir pl suggest. i bought a new 1.5t window ac and after installation set temp to 23 c.
    from the night of the installation if find
    1) compressor takes about 5 minutes to start after switching on the ac till then the lcd display shows “UP” (installation person said it happens for the first day only)
    2) in the middle of the night again the compressor was off and only fan running for a long time . the lcd display again shows “UP”. and room was not cool.
    Is this the first day blues or a defective unit pl advise
    Thanks

    • Abhishek Jain

      Hello Mr Tapan,

      It sounds like a defective piece, as the compressor should not go off at Night. Can you check if it is running in the right “mode”? Make sure it is in cool mode.

  • meenal

    I have 1.5 ton ac how much bill will come if i set it at 13 degree celsius

    • Abhishek Jain

      Hi Meenal,

      Are you sure you want to set it to 13 degrees?

  • raza

    Hi, I wanted to know how much average time a room ac takes to achieve a set temperature from the time it is switched on, assuming set temperature was 24 degrees.

    • Abhishek Jain

      Depends on room size and in general on the heat in the room and heat outside. However if you have sized your AC properly, it should not take more than 15-20 mins.

  • Rishabh

    Hi,
    I am looking for an air conditioner which is power efficient as well as should have a good performance at the times when there is high outdoor temperatures..
    I concluded to go for an inverter ac of 1ton..

    The thing which is confusing me is operating temperature of compressor. In my city temperature hits 48 sometimes 49 in peak summer.. But all good brands (general, daikin, mitsubishi, etc) gives operating temperature till 46.. I have seen only hitachi claiming it is designed to work on 52…

    I this condition, how significant is this criteria while choosing the right one or is hitachi the only option left for me?

    • Abhishek Jain

      Hi Rishabh,

      Typically if the temperature is very high around the outdoor unit and there is direct sunlight on it, the efficiency of condenser goes down. To a certain extent it will try to work by consuming more electricity, but if the temperature goes really high, the compressor stops working and the air does not get cooled. However you can avoid that situation by making sure that the ODU does not face the sun directly and is in a place that has a good shade or is surrounded by plants that keep the temperature around the ODU cooler. So if you go for a model which has operating temperature of 46, you will have to take care in placing the ODU in a place that is cooler as compared to outside and does not get any direct sunlight.

  • saialuka

    we have 1.5 ton 3 star a.c during night time temperature changes automatically from 22c to 24,25,26c gradually is thi normal in energy saving mode.

    • Abhishek Jain

      Well if temperature increases, it will certainly save energy. Unless it is causing any discomfort, it should be good. Every brand has different kind of energy saving modes. In some ACs, the AC actually switches of completely for some time in energy saving mode and restarts automatically after some time.

  • amjad

    What is the ideal position for remote setting for Electricity saving. there are three options 1- Auto 2-Cool 3-Dry. I have Panasonic Inverter, Econavi Split AC.

  • Abhishek Jain

    It will depend on your temperature setting more than the option setting.

  • ASMA

    plz help me ,i want to know that .the thermostat is in every AC’s??? i have Sabro Split Ac but its compressor is not turning off when room temperature is maintained.Where is problem????

  • Abhishek Jain

    Hi Asma,

    All ACs have thermostat. So either your AC is smaller for your room or certainly there can be a technical problem.

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