Electricity Saving Tips For Homes And Offices

Split or Window … which air conditioner should you buy?

By on January 23, 2014

Air Conditioner Should I buy a split air conditioner or a window air conditioner? This is a question that many air conditioner buyers thinks of, before making a purchase. And we keep getting this question quite regularly at Bijli Bachao. It is not just about split or window, but about a whole lot of things that should be considered while buying an air conditioner.  Air Conditioner is an appliance that can significantly blow up your electricity bills and utmost care should be taken while buying one. With this article we would try to provide you some guidelines on things to take care of before making a purchase decision for an air conditioner. Please note an air conditioner bought once will go on for next 10 years at least and thus it is important to make a right decision.

Split vs Window

Buying a split or a window is something that worries a lot of people. But from energy efficiency perspective there is no preferred choice. Both split and window can be equally efficient. What matters is EER or Energy Efficiency Ratio of the air conditioner. EER represents the amount of cooling an air conditioner can provide per watt of electricity it consumes. Bureau of Energy Efficiency rates air conditioners on its star rating based on EER of air conditioners. Higher the EER of air conditioner higher the star rating it will have. So a 5 star rated air conditioner provides more cooling per watt of electricity used.

Both split and window can have high EER ratios. But it is observed that Split air conditioners have more number of models in BEE 5 star rating as compared to Window air conditioners (check our research on air conditioners at this link: link). So if you are looking for high efficiency air conditioners then split air conditioners can provide you more options.

The main difference between the two is that window air conditioner has a single unit whereas split air conditioner has 2 units (indoor and outdoor). Split is lot more silent in operation as compared to window and looks aesthetically pleasing, but is relatively more complicated to install and requires more space as compared to window air conditioner.

Right sizing an air conditioner is very important

The most important thing that one should figure out before buying any air conditioner is the right size of the air conditioner. This can significantly impact your electricity bills. And from size we mean tonnage of air conditioner. Every room that is cooled has a certain amount of heat that depends on:

  1. Size of the room. This determines the amount of air in the room that needs to be cooled.
  2. Number of people in the room. Every human being emits heat and air conditioner needs to cool it.
  3. Amount of stuff kept in the room. Please note every item kept in the room will get cooled from the air conditioner, so lesser the stuff, lesser the electricity air conditioner will consume.
  4. Number of electrical appliances in the room (most electrical appliances emit heat, especially lights). Incandescent light bulbs can increase cooling load.
  5. Windows in the room. More the windows, more is the heat coming from outside. Well-insulated windows reduce cooling load. Check our insulation section for more details: http://www.bijlibachao.com/Save-Electricity/Insulation/
  6. Walls facing the sun can increase cooling load. Touch your walls and windows to check if they are hot or not and using the tips in insulation section to prevent heating of the room.

The amount of heat in a room and that coming in from walls and windows is represented in BTU (or British Thermal Unit). BTU is sum of heat from all the above-mentioned sources.

Every air conditioner has a cooling capacity, which is represented in BTU/hr. It is the BTUs of heat that it can remove in an hour. If the heat coming in the room (in BTUs) is more than the heat that air conditioner can remove, then the air conditioner will not be as effective. Thus an undersized air conditioner cannot remove heat effectively and the compressor of the air conditioner will continue running all the time thereby consuming more electricity.

With an undersized air conditioner, you will have to keep thermostat temperature at lower setting (say 18oC to 20oC) to get the same effect that you can get with keeping a right sized air conditioner at 25oC (which is ideal air conditioning temperature: article link).

An oversized air conditioner can cool your room right and quickly but it is ineffective in removing the humidity in a room. It will have shorter run cycles but all air conditioners are designed for optimum run cycles and if the cycle is shorter than that then the efficiency is reduced (source: energy star).

So every air conditioner is designed to run at optimum efficiency only if it is used as per the right size. So always size the air conditioner properly. You can use the calculator available at this link before buying an air conditioner: http://www.lg.com/in/support/ac-tonnage-calculator.

If you are not sure about what size to buy, you can always buy an inverter technology air conditioner, as it adjusts to the size and requirements of the room automatically, and thus makes optimum electricity consumption. To check more about inverter ac see our article: Air Conditioners with Inverter technology can help save electricity.

Look for the right options in the air conditioner

In a previous article (Various modes for running air conditioners and their impact on electricity bill) we discussed about various modes of air conditioners and their impact on electricity consumption. It is very important to figure out if the air conditioner has all the modes as per your requirement. If you live in humid area, a dry mode is important. Any air conditioner with energy saver mode and features should be preferred.

Star rating is for real

BEE Star rating of air conditioner do matter a lot. Any air conditioner would consume anywhere between 1-2 units per hour of usage based on tonnage, efficiency and size. Which means if it is used for 10 hours per day, it can consume about 10-20 units in a day or 300-600 units a month (for 10 hours of use daily). At an average rate of Rs 6-7 per unit (you can check your per unit rate using our calculator: Online Electricity Bill Calculator – For all states in India) it can be close to Rs 1800-4000 per month. If your usage is high then the yearly cost of an air conditioner can go very high. In case of high usage, incremental cost of buying a higher star rated air conditioner can easily be recovered in a few years. Please note that the air conditioner will work for at least 10 years and the electricity prices are on a rise. Buying an efficient one while buying a new air conditioner can prevent a lot of heartburn for you in future.

It is important to make a right decision while buying an air conditioner, as it is a long-term utility for you. Do not let lucrative deals, discounts and persuasion by a sales person impact your decision to buy an efficient appliance. A wrong decision on an appliance like air conditioner can significantly impact your electricity bills. We are trying to work out a calculator that can help you choose the right air conditioner for you and hope to release it soon. Till that time you can check the list of top ten most efficient air conditioners at: Top Ten Air Conditioners in India by electricity consumption and size.




Have question, doubt or comment? Leave a message

There Are 43 Comments

  1. sumit says:

    hi abhishek,
    can u tell me whether central ac system is better than 8 one ton ac or not


  2. naren says:

    i want an ac for a small room which one should i go for ?? windowed or split?i may have to shift my residence too so
    which is best, effective and gives more life? and which brand should i buy?

    • Abhishek says:

      Hi Naren,

      If you shift frequently then window AC will be easier to move. But please note that you will not get inverter tech AC (which is the most energy efficient AC) in window models, also energy efficiency of window models is 1 level lower than split models (so BEE 5 star window AC is equivalent to BEE 4 star Split AC). As for the brands, I would say Hitachi has the most energy efficient window models and is great on quality as well. You can also look at Carrier which is good too.

      Hope this helps.


      P.S: Please help us by taking survey on this link: http://www.sustain-it-india.com/index.php?r=survey/index&sid=687551&lang=en

  3. Dr Piyush says:

    I want to take 1.0 ton ac. But I am confused which one I should go for 3 stat, 5 star or Invetrer AC?

    I am living in Pune. 6 th Flor Flat & one more Floor above. Room Size 3m length X 4 m width & 10 feet Height. East facing window & 15 feet wondow with one door. I thinmk i should go gor 0.8 or 1.0 ton? Please guide.

    My usage is very low. 6-8 hour usage for Four month in Year.
    Considering 10 years life of AC, is it really worth going for 5 star/Inveter AC?

    If yes, if you can explain with some figures will be great. I want to understand how I can recover initial extra cost of purchasing 5 star/Inverter Ac as per my usage explained.

    If you can help I don’t mind to go for Inverter AC purchase.

    I want to take AC in this week. Please help.

    • Abhishek says:

      Hello Dr Piyush,

      If you go for fixed speed AC then you need 1 ton AC, else you can even work with 0.8 ton inverter AC.

      To give you calculations, 1 ton BEE 3 star AC would consume about 0.8 units in an hour (depending on multiple factors). Your yearly usage is for 960 hrs. So about 768 units in a year. If you are between 300-500 units slab in maharashtra, cost per unit of electricity is Rs 8+. So yearly cost of electricity becomes Rs 6144. If you go for BEE 5 star 1 ton AC then you save about 15% or about Rs 920 per year. If you go for inverter tech, you would save 30-40% per year, so roughly about Rs 2000 per year. Average life of AC is 10-12 years.

      A BEE 3 star split AC from a decent brand would not cost less than Rs 25-26K. And inverter tech AC from a good brand start from about Rs 30K. So your payback for the extra money that you pay can be as low as 2 years for inverter tech AC.

      Hope this helps.


      P.S: Please help us by taking survey on this link: http://www.sustain-it-india.com/index.php?r=survey/index&sid=687551&lang=en

  4. Nisha says:

    Hi Abhishek,

    I am planning to buy split ac for a 190 square feet room. Im residing in Coimbatore, My room has two windows and it is not facing the sun. My usage will be 4 hours a day. I would like to buy an ac which doesnt significantly blow up my electricity bill. I am told LG and Samsung will create noise after 2 years. One of the dealers suggested Haier and told it has a very longlasting compressor and doesnt give many complaints. Please advise.

    Warm Regads,

    • Abhishek says:

      Hi Nisha,

      Your room will need anywhere between 1.45 ton (if the room is lower floor, less sunny and the walls do not get too hot) to about 1.75 ton (if the room is top floor, or very sunny, or the walls get too hot). Your usage of AC is less (I am assuming that you will use it only in summers), so going for BEE 3 star AC sounds good. Now the tonnage I mentioned above will be for peak summer day and for the use during day time. If your usage is mostly at night, then the tonnage requirement will be lesser (however while sizing mostly the peak summer day is used). Also even if your room gets too hot, I would suggest going for 1.8 ton AC rather than a 2 ton AC. Also please note that a 1.5 ton inverter tech AC can cover a tonnage range of 0.3 to 1.75 tons, and it costs about Rs 40-45K. So just in case if you go for a 1.8 ton AC, do try to see if you can get 1.5 ton inverter tech for the same cost.

      As for the brands, dealers suggest brands for which they have inventory or good margins. If you want to go for one with good technology, then we recommend going for any of the japanese brands (Hitachi, Mitsubishi, Panasonic, General, Daikin, Sharp) or Carrier or Bluestar. LG and Samsung have a larger service network.

      Hope this helps.


      P.S: Please help us by taking survey on this link: http://www.sustain-it-india.com/index.php?r=survey/index&sid=687551&lang=en

  5. Manish says:

    I want one split ac to be used for two bed rooms
    Is it available in market ?

    • Abhishek says:

      There are portable ACs in the market, but not a split AC that can be used in two rooms. Or you can go for multi split which has one outdoor and 2 indoor units.


  6. vamshi says:

    Which a.c cools fast window or split

  7. Satya says:

    In continuation of my earlier query, please advise AC of which company I should go for ?

  8. Satya says:

    Sir, I hv a room size 18X14 having 3 CFL lights 2 fans and a LED TV 46″ with home theater. Please advise what kind of AC (Split / Window) and tonnage should i go for. Pls advise the difference between a 5 Star ac and an AC with inverter technology in terms of electricity effeciency.

    • Abhishek says:

      Hi Satya,

      Firstly can you please let me know the city where you live in? The tonnage depends on climatic conditions and without knowing that it will not be possible for me to suggest the size. As for the difference between star ratings, each star rating represents a range of efficiency and with every increase in star rating, you can assume 7-14% efficiency improvement. The benefit of inverter tech is that it is has auto adjusting tonnage. So it can adjust to the needs of your room. Also the tonnage requirement depends on the heat load in the room and heat load is not always the same (it is low at night, high during the day… it is low in march high in may). So the best thing about Inverter Tech is that it automatically adjusts its tonnage. Ovsersized ACs are inefficient and consume more electricity, so suppose requirement of your room right now is 1.2 ton and if you are running a 1.5 ton AC, then it is inefficient (even if it is a BEE 5 star rated 1.5 ton AC). Earlier there were only fixed speed ACs available, so you did not have an option of auto adjusting AC.

      Now how much electricity efficiency can inverter tech provide? If you compare a right sized BEE 5 star fixed speed AC and right sized inverter tech AC, just because of changing climatic conditions, it provides at least 20% savings. But if suppose your room’s requirement is 1.2 ton and you put a 1.5 ton AC, then 1.5 ton inverter tech will automatically scale down to 1.2 ton whereas fixed speed 1.5 ton inverter AC will run at 1.5 ton and thus savings will be much more higher in 1.5 ton inverter tech AC (up to 40-50%). So savings truly depend on how you size your AC.

      You have also asked a question on brands. Frankly every brand has pros and cons, so we do not recommend any specific brand. But purely from Technology/reliability point of view (not from post sales service perspective), we recommend going for a Japanese brand (Hitachi, General, Panasonic, Daikin, Sharp) + Carrier + Bluestar. From post sales service point of view, the likes of LG and Samsung have a large network for post sales service.

      Hope this helps.


  9. nikhilesh chaturvedi says:

    Hi Abhishek,
    i wanna buy an a.c which a.c should i buy split or window…. Room size is 10X 12… I live in Bikaner (Rajasthan)…

    • Abhishek says:

      Hi Nikhilesh,

      Your requirement would be between 1 and 1.1 ton of air conditioning. If you live in your own house or do not move locations frequently, then I would suggest you to go for Split AC. Else you can go for window AC.

      Hope this helps.


  10. saurabh kabra says:

    Hello Sir,
    I want to buy a 1.5 ton ac.But i am confused with star ratings as people say they hardly matter.
    Secondly, what is the difference between split and window ac on basis of performance and features.
    Please help in solving queries

    • Abhishek says:

      Hello Saurabh,

      Here are a few things that should be considered while buying an AC:

      1) Tonnage of AC: Depends on several factors, but primarily on size of room, city where you live in, window sizes, people in the room. Oversized AC consumes more electricity, and undersized does not cool properly.
      2) Star Rating: Choice of BEE 5 star/inverter tech or a lower rating depends on your usage of AC. If your usage is more than 1000 hrs (with traiff more than Rs 5), it is better to go for higher efficiency models.
      3) Brand: Some brands offer better reliability/technology and some have better service network. One has to factor in both.

      As far as your statement regarding star rating is concerned. They do matter, just that monetary benefit (capital cost vs electricity cost) depends on your usage of AC. As far as split and window are concerned, the standards for star rating is the same for both window and split, so you will find both window and split models with BEE 5 star rating. However split models offer extra scope for efficiency and thus you would find that some of the split models have higher efficiency than the best BEE 5 star rated window models. Although I feel that the biggest factor that should drive your decision between split and window should be your chance of moving from one location to another. If you keep switching homes frequently, then a window AC provides a lot of ease. Also for split you need to create opening in the wall, and at many rental places, that is not allowed.

      Hope this helps.


  11. sudhir jain says:

    Room size 12*10sq ft and i am in east delhi.
    and any other option like window or split.

    • Abhishek says:

      Hello Mr Jain,

      For 120 sq ft room in Delhi a 1 ton air conditioner would be sufficient. You can go for either split or window based on the setup you have. For Split you will have to put a hole in the walls, whereas for window you would not need to get all that done. You will get much more energy efficient options in Split than in Window (although a BEE 5 star rated Spilt will be more or less as good as BEE 5 star rated window AC). Depending on your usage you can choose star rating: if it is more than 1000 hours in a year and your electricity rate is about Rs 5 a unit, it is advisable to go for BEE 5 star rated AC. Else if your usage is low, you can go for a BEE 3 or 4 Star rated ACs as well.

      Hope this helps.


  12. sudhir jain says:

    Dear sir Good Morning,i am looking ifb split ac model no IACS18BF5TP 1.5T 5 star rs 35,880/
    free stabliger, free instal, free brackets,
    so pls tell me best for me or not like maintenance electricity consume etc.

  13. Pranay Shah says:

    Thanks for the information.
    Room size : 85 ft2, 1 wall facing west, top floor, 1 bed, 1 cupboard, 3 person,
    what would the ton of AC which is should select?

    • Abhishek says:

      Hello Mr Shah,

      Although we also need to know the city where a person lives to find out the right size, but 85 sq ft room is too small and I do not think you will need more than 0.75 tons of air conditioning for that.


  14. air conditioning installation says:

    Great post,thanks for sharing with us…

  15. Vivek Singh says:

    Most of the people are too confused. Thanks for explaining the great difference between the two. I am using split ac and it seems to be perfect as per my need and requirement.

  16. air conditioning Rochester NY says:

    Informative post………

  17. Raunak says:

    Extrmly confused btwn both the ac’s
    i hav a transferable job and get transferd evry 5-6 yrs
    The tonnage nd starr ratings i hav decided
    I knw window ac is quite economical
    But split is more efficient since it has two unit

    Wat wud u suggest for me
    One more thing wat is the cost range of intallation split ac

    • abhishekjain203 says:

      Hi Raunak,

      5-6 years is a long time. Life of an AC is about 12-15 years, so you may have to shift it only once or twice. But Split AC involves making a hole in the wall for installation. If it is permissible in your house to do so, then you can go for split as well. Also regarding efficiency I would say that there are several models in Window ACs that will be as efficient as a split AC.

      My recommendation to you would be to go for an efficient window AC.


  18. nilanjan chakraborty says:

    Hii. if a 5 star AC have been used for 02 hours per day ..how many Electric charge may be paid for that ?

  19. SoGoodToBuy says:

    Window units are really cheap but not as efficient as a split. We would always recommend a mini-split air conditioner

  20. Emily Victor says:

    I think it is depended on you. Suppose you have a big house then you must install central AC otherwise do not need to use this. It is very difficult to say as a professional member. I just say you that when use small ac for small house and use big for big house. And only a professional member can exactly say which ac will be better for you.

  21. KANISHKA says:


  22. ⚡Ravi Dabbiroo ZYCE⚡ says:

    dear abhishek ..! couple of q’s at what height should the split ac be mounted (from the floor) in a room with ceiling height of 10 feet? total area of room 150 square feet… and will 1.2 tonn be good or should i go for 1.5 tonne for my room ?

    • abhishekjain203 says:

      Hi Ravi,

      The ideal height for installation of split air conditioner as recommended by most installation manuals is at least 2.3 m above the ground. It is ideal to install the AC in a direction that it covers the length of the room rather than the breadth. As for the tonnage, it depends on multiple factors. I guess the bluestar calculator link mentioned on this page is not working. You can try this one from LG: http://www.lg.com/in/support/ac-tonnage-calculator. It all depends on heat and humidity in your city as well as windows in your room.


  23. Abhishek says:

    Hi Amit,

    I think I already replied to you on this:

    “6 meter pipe should not be a big problem. Although you need to analyze how much the kitchen heats up your room. Having said that 1.1 ton inverter tech sounds good for your room in most cases unless the kitchen heats up the wall a lot. Also if your use is more at night then the kitchen effect will be minimized.

    A 1.5 ton AC (fixed speed) will cool quickly, but if it is oversized then it will increase your electricity consumption significantly. If you go for 1.5 ton inverter tech, then it should work well in all cases (reason being that the inverter tech ACs adjust their tonnage as per the room’s need and a 1.5 ton inverter tech AC can cover form 0.3 to 1.75 ton range). So if you are thinking of going for 1.5 ton, I would recommend you to go for inverter tech. Sharp has some good models in 1.5 ton inverter tech as well and if you get a deal on them, then nothing like it.”

    Hope this helps.


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