Air conditioners have evolved a lot over the years. The models produced in the year 2000 used 30 to 50 percent less energy than the ones that were manufactured in 1970s. Nowadays, the newer models are designed with better energy efficiency features.

Before going into the details about the energy consumed by air conditioners, it is essential to know how the device works. Air conditioners work on the same principle as a refrigerator, where circuit of pipes and a pump form the cooling system. The room is cooled by the indoor cold evaporator coil, and the hot coil expels the heat outside the rooms.

The cost of running an AC depends on various factors like:

  • The type of AC used
  • How long you use it every day
  • Price of energy or power
  • Usage of air conditioners
  • Energy-Efficiency Ratio or the EER of the AC unit


Energy Consumption of Air Conditioner

Presently, AC models with 1 to 5 energy star rating are available in the market. A 5-star model saves maximum energy, and the 1-star rated model consumes more electricity. A regular AC used for residential purpose has a 5,500 – 14, 000 BTU/hour range. If the climate is hot, it is recommended to purchase an AC with higher start rating. The ratings are awarded by BEE (Bureau of Energy-Efficiency).

The electricity charges are based on the units of consumption (1 unit = 1 kWh)

For example: 10 numbers of 100 W bulbs when switched on for 10 hours will consume:

  • 10 X 100 W X 10 H = 10, 000 watt hour = 10 kilowatt hour = 10 units.

Similarly, An AC with 2,000 Watt power input if operated for about 8 hours per day will consume:

  • 2,000 watt x 8 hours = 16 kilowatt hour = 16 units ERR

Energy Efficiency Ratio for AC:

  • EER = cooling capacity / Power consumption (both in Watt)
  • EER of 1 TR (about 3,514 W) capacity air conditioner consuming power 1,500 W = 3,514/1500 = 2.34
  • Star Rating System based on EER – 1-Star: 2.3, 2-Star: 2.5, 3-Star: 2.7, 4-Star: 2.9 and 5-Star: 3.1


You can lower the energy consumption by following these simple steps:

Use Portable or Window Units:

If you are not cooling the entire house, then use a portable AC to cool only the area where the cooling is required. They use 50% less energy as compared to a centralized air unit to cool the same space.

Programmable Thermostat:

It is advisable to go for a programmable thermostat. This helps you to switch the AC on and off as per the program set by you. It avoids excessive utilization of power and saves almost 15 percent on electricity bills.

Service Your Unit:

Although your air conditioner requires only basic maintenance, it should be kept clean and free from dust, particularly if you live in areas where there is a lot of pollution.  The seeds or pollen may stick to the air filters, which will make the device work harder, thereby decreasing the energy efficiency.

Check the Ducts:

Make sure that the space in your house, where the ducts run through without air conditioning are properly insulated. This will help in keeping the air cool.

Don’t Overlook Fans:

Although we rely on ACs to keep the area cool, having a few fans around is helpful too. Fans are useful in circulating the air around. Moreover, the energy consumed by fans is lesser than an air conditioner unit. Therefore, it is always a great idea to have fans as a backup.

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