Electricity Saving Tips For Homes And Offices

Before Renewables think Energy Efficiency

By on April 22, 2016

There is lot of buzz in the world around renewable sources of energy and even energy efficiency. Renewables truly have potential to solve all the energy problems in the world, but one has to think efficiency first. If the electrical and electronics systems are not efficient then the size of renewable system required will be more, which will not just require more space but will also be more expensive. So although renewables and energy efficiency are treated as separate areas but they are truly very interrelated and one should take them together.

Renewable energy is also electricity

When we think of using renewables (solar or wind or any other source), we should first accept that we are using these sources to generate electricity. The appliances that we will connect to these sources will be electrical appliances that will consume electricity. The bigger the need of electricity, bigger is the system required to generate electricity. As renewable sources are not very cheap, we have to understand that a bigger system will be expensive. To reduce the cost, the best approach is to reduce the electricity requirement of the systems connected to it and using efficient appliances is the best way to do that.

Plan for efficient appliance before renewable

Before you start your renewable project analyze the systems that will run on it. Plan for these before buying a PV (Photovoltaic system):

  1. Try replacing incandescent bulbs, inefficient tubelights and halogen lamps with CFLs, energy efficient tubelights or LEDs for the best case.
  2. Try replacing old inefficient ceiling fans with energy efficient ceiling fans. Please note that ceiling fans can be biggest contributor to your electricity bills in percentage terms (especially if you do not use air conditioners).
  3. If you plan to use solar water heaters, make sure that the insulation is perfect for that. You can try using thermal insulating paints to make sure that standing losses on the water heater is less.
  4. If you are planning to use photovoltaic for air conditioners, make sure that the thermal insulation of the room is proper so that the heat flow in the room is less.
  5. LED TVs are much more energy efficient than any other type of TV, thus plan for replacing the same before using Solar to power your house.
  6. Replace all old appliances with energy efficient appliances so that the connected load of the house is less.

Reducing connected load can have multiple benefits

We talked about connected load in one of our earlier articles (link). Connected load is a value that is derived by summing up wattage of all the appliances connected to a meter. Reducing the same not just helps you reduce your electricity bill; it also helps you if you are planning for a renewable project. Lesser the connected load, lesser the electric bill and smaller the size of a renewable system required.

So always think efficiency before renewable.

Reference: Go Solar California

Please use the commenting form below to ask any questions or to make a comment. Please do not put the same comment multiple times. Your comment will appear after sometime. Also please note that we do not reply to emails or comments on social media. So if you have any question, please put it in the form below and we will try to reply to it as soon as possible.

Add comment

E-mail is already registered on the site. Please use the Login form or enter another.

You entered an incorrect username or password

Sorry, you must be logged in to post a comment.


by Newest
by Best by Newest by Oldest

I want to run one fan for 8 hrs,two CFL for four hrs,one LED TV 20 inches for to hrs.,how much it will cost including all components/ accessories. and who means company products are best.,The location is in Rajasthan on the fringes of the Great Indian Thar Desert.


Dear Bijli bacaho I want to install solar panel on my roof top for domestic use.Where I can able to get all the details for installation of solar panel .I am coming from state of odisha.


First of all you are doing a great Job in guiding people on the details difficult to assess. I need your support in assessing the inverter and battery requirements(please suggest best and lowest maintenance product. Battery I will go for amaron brand).

I need to run 2 fan(6 hrs), 2 CFL(6hrs), 1 mixer charging point(30 Min), 1 LED 32 inch TV(1 hour), 2 tube lights(6 hours)

Please suggest the usage that would be there and the ideal combination of battery and inverter (including product name)

Thanks in advance


Team, Please suggest for the above appliances what would be the ideal inverter value ?

Abhishek Jain (Mod)

About 1 kVA will be safe.


Wow! This is such a great blog on solar energy. I am planning to create a project report and see if we can setup a mini solar power plant in our cold storage for industrial use. You blog definitely helped and I've just begun research. Great information. thanks a lot Abhishek! (I'm assuming you're the founder/writer/owner of BijliBachao?)


Prateek from UP (it will be a great victory if I'm able to setup a solar thingy in UP!!!)

Abhishek Jain (Mod)

I am glad that you found it useful Prateek.


Dear Abhishek,

Read a elaborate details of UPS. thanks for the details. I want to run 47" LED TV, set top box , 2-3 fans, 4 tube lights, laptop and possibly a mixer for few minutes in between. how do i calculate how much battery and KVA for Inverter? Please help me with this. Also in i want to add AC 1 ton to this how much do i need to add?

best Regards,


Abhishek Jain (Mod)

Hi Suvarna,

A 47 inch TV would be rated about 120 watts, set top box would be about 10 watts, 3 fans will be about 270 watts, 4 tubelights will be about 160 watts, Laptop would be about 60 watts, Mixers range between 350 to 750 watts, so if we take maximum then 750 watts for it. So total would be 120+10+270+160+60+750 = 1370 watts. So about 2 kVA inverter would be needed (it will reduce significantly if you do not use mixer). A 1 ton AC would need another 3 kVA so total 5 kVA inverter if you add AC as well.

To calculate battery requirement, you need to look at the hourly usage of these appliances on backup.


Hi, I am residing in a Flat, Paldi area, Ahmedabad.

My flat is having a Balcony of 3 Ft width, and approx 10 Ft long.

I would like to install a Solar System to generate power for my house.

I would be using power for following at a time:

01. Air Conditioners - 2 Nos, each of 1.5 MT and 1 No of 2.5 MT

02. Ceiling Fans - 3 Nos

03. TV - 1 No

04. Tube Lights - 4 Nos

05. CFLs - 2 Nos

06. Freeze -1 No of 200 Ltrs

Also use power for a Washing Machine - optional case, when washing machine would be running, some of the above instruments would be off.

I would like to know the following details:

A. Looking to the available space in my balcony in South West (Balcony area 3 Ft X 10 Ft), Would it be possible to install Solar System?

B. How much capacity / power we would require to generate?

C. What will be the cost to buy and installation of Solar System - Approx?

D. Would be grateful if you could let me know the details of instruments with proper technical details to be purchased.

E. From where I can purchase these instruments? Can you please provide the details of reliable vendors in Ahmedabad?

Anticipating your kind co-operation.

With Regards,

Mitul Shah

+91 9727705023

Abhishek Jain (Mod)

Hello Mr Shah,

What will be the daily usage of these appliances in hours? Do you really want to run ACs on solar power? It will significantly increase the size and cost of Solar PV system.


Dear Abhishek,

Thanks for the prompt reply.

If it is cost effective and space will be sufficient, I would like to run AC on Solar System.

Also I have requested for another details. Would be grateful, if you could reply in detail on my Email ID: [email protected]


Mitul Shah

+91 9727705023

Abhishek Jain (Mod)

Hello Mr Shah,

There are two types of sizing requirements for Solar PV systems:

1) Sizing of Panels and batteries which depends on total energy (or units consumption). This depends on your usage of appliances and that is why I asked you for usage of all the appliances. Now 1 kW solar PV panels can produce 5 units of electricity in a day. Now if we look at your appliances:

- A 1.5 ton AC would consume about 1.5 units in an hour (can be more or less depending on the efficiency of the AC)
- A 2.5 ton AC would consume about 2.5 units in an hour (can be more or less depending on the efficiency of the AC)
- A ceiling fan would consume 0.075 units in an hour, so 3 of them would consume 0.225 units in an hour.
- Power consumption of TV depends on type and size. If it is old CRT TV of 32 inch, then it would consume about 0.25-0.3 units in an hour. If it is 32 inch plasma again it would consume 0.25-0.3 units in an hour. If it is LCD 32 inch it would consume about 0.12 units in an hour and LED 32 inch would consume 0.065 units in an hour.
- 4 tubelights assuming they are all T8 tubelights with electronic choke would consume about 0.152 units in an hour.
- 2 CFLs assuming they are 25 watts would consume about 0.05 units in an hour.
- A 200 lts refrigerator would consume about 1 unit in a day or 0.04 units in an hour.

So an approximate consumption per hour assuming everything is running together is 1.5+2.5+0.225+0.3+0.152+0.05+0.04=4.76 or approx 5 units in an hour.

So a 1 kW panel would give about a 1 hour backup for you (assuming everything is running together). A 1 kW Panel would cost about Rs 55000. Battery to store 5 units would cost about Rs 40000. The space needed for 1kW system would be about 80 sq ft.

2) Sizing the inverter: This depends on total wattage of appliances running together. Now if we assume everything you mentioned is running together. Lets look at wattages:

1.5 ton AC: about 1900 watts
2.5 ton AC: about 3000 watts
3 ceiling fans: 225 watts
1 TV: 300 watts (assuming CRT 32 inch).
4 tubelights: 160 watts (assuming T8 tubelights)
2 CFLs: 50 watts (assuming 25 watt CFLs)
1 refrigerators: 300 watts (peak power)

Total is about 6000 watts. To get approximate VA value for this, we can divide it by 0.8 (assuming power factor of 0.8), it comes to approx 7500 or 7.5 kVA inverter.

A 7.5 kVA inverter costs about Rs.2,85,000. However assuming you will not run all the appliances together, you would need at least a 5 kVA inverter to run the ACs. A 5 kVA inverter would cost about Rs.46,800 (would cost more if you go for a 3 phase 5kVA inverter).

So total cost would be Rs 55000 + Rs 40000 + Rs 46800 + (extra for wiring installation, charge controllers, etc) = Approx 1,50,000 and it would provide 1 hour backup. And would need 80 sq ft space. There may be 30-40% subsidy on top of it but currently I am not sure if it is available. And it will save you about 5 units in a day.

Hope this helps and gives you some idea.


Hi Abhishek,

I have a battery of 150Ah invatublur i have to buy new inverter to carry load for 1 l.c.d t.v + 4cfl+2fans+1ro+1washing machine. What should be the power of inverter and of what company will suit best.

Abhishek Jain (Mod)

You should go for 1500 VA inverter. You can go for any of the top brands like Luminous or Su-kam.


Please consider the area available?????????????????????????????????????


Send this to a friend