All You Need To Know About AC Power Consumption

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An air conditioner, as everyone knows is a power guzzler. But how much power do they consume per hour? Are there methods to reduce power consumption? What should you look at when buying an AC so that the power consumption is lesser? Let us explore it all in detail.

Reading the BEE Energy Label of Air Conditioners

BEE label showing power consumption of AC

Let us take a look at the key information that a BEE label conveys and how it affects the performance of the AC.

ISEER- Refers to Indian Seasonal Energy Efficiency Rating. This is calculated by considering the efficiency ratio of the AC at temperatures ranging from 24-43 °C for 1600 bin hours. The higher the ratio, the lower the energy consumption. This value helps differentiate between different ACs that fall under the same star rating. When comparing between 2 ACs, opt for one with higher ISEER.

Label Period- The current labeling period is valid till December 2024. A 5-star AC in the previous label period ending December 2022 would be just a 4-star AC in the current period. Hence, it is important that you look at the labeling period to understand whether a 5-star AC is truly one!

Cooling Capacity- Refers to the ability of the AC to remove heat from a given space. Most often, a 1-ton AC has around 3500-watt cooling capacity, while a 1.5-ton AC has a 5000-watt cooling capacity and a 2-ton AC has around 6000-watt cooling capacity.

Electricity Consumption- Refers to the annual energy consumption over 1600 hours at temperatures ranging from 24-43 °C. Dividing this value by 1600 can give a rough idea about the energy consumption of an AC in ideal conditions.

Compressor Type- Cooling devices like AC and refrigerators have either fixed-speed or variable-speed compressors. A fixed-speed compressor, as the name suggests runs at a constant speed. When the thermostat detects that the room has reached the desired temperature, it cuts off the compressor and stops working till the thermostat detects a rise in the temperature. So, it is always in an ON or OFF mode. These types of compressors usually have higher wear and tear, affecting their durability and they have higher energy consumption too.

A variable speed compressor never switches off. Instead, it runs at a slow speed when the room reaches the desired temperature. This way, there is no constant ON-OFF. So, wear and tear is lesser and it makes lesser noise too.

Power Consumption of Split AC vs Window AC

AC power consumption of window AC
Window AC

Window ACs may seem redundant. But, that is not the case. Even now, a lot of people opt for window ACs for their budget-friendliness and easiness of installation. But, when it comes to power consumption, are they better than their sophisticated counterparts- split ACs?

Not really. Split ACs are better because of the superior insulation it provides and higher EER rating ( Energy Efficiency Ratio). A 1.5-ton 5-star window AC from LG has an annual energy consumption of 1053 units, while an LG split AC with the same capacity and energy rating has just 685 units of annual energy consumption.

Similarly, a 1.5-ton 3-star window AC from Lloyd has an annual energy consumption of 1180 units, while a split AC with the same rating and tonnage has just 911 units of annual energy consumption.

You may also like our article on 3-Star vs 5-Star AC

Annual Energy Consumption of ACs As Mentioned In BEE Label

AC power consumption

In the above examples, we have made a comparison between different models using the annual energy consumption mentioned in the BEE ( Bureau of Energy Efficiency) Label. But, does this mean that a 1.5-ton split AC uses just 685 units if you run it 24×7 for a year? Obviously not!

The BEE label uses a different methodology to calculate the annual energy consumption. The value mentioned is measured based on the bin temperature range of 24- 43°C and 1600 operating hours. Using the data from the National weather database for 54 cities across India, they calculate the number of hours for which temperature stays at 24°C, 25°C, and so on up to 43°C. Then, the power consumption of AC is measured at each temperature range at full capacity and 50% capacity. Further calculations are done as per IS 1391 part 1 and 2 of the Room Air Conditioner Specification to calculate the Annual Power Consumption, ISEER, and other information you find on the label.

The objective of this article is to help you develop an idea about how power consumption changes depending on the tonnage and the energy rating. So, we are taking a simplistic approach of dividing the annual energy consumption by 1600 hours. But, the fact remains that the actual energy consumption may differ depending on various factors about which we talk next.

Factors Affecting the Power Consumption of An Air Conditioner

AC power consumption

As you would have understood, the energy label of air conditioners helps us compare different models to understand which one consumes the least power. But the data cannot give the precise value of how much power your AC will consume as it depends on various external factors. They are-

Outdoor Temperature- Ambient temperature has the greatest influence on an AC’s power consumption. The higher the ambient temperature, the higher the load on the AC and hence, the higher the energy consumption.

Number of People In The Room– Newer air conditioners detect the temperature inside the room and run at peak power till it is brought down. So when a large number of people are there in the room, more heat is generated inside and hence, the AC will have to run extra hard, thus consuming more power.

Insulation of The Room– Again, the same principle applies as mentioned above. When cold air escapes from the room, the AC keeps working hard to bring down the temperature. This is why you should keep the door and windows tightly shut when switching on the AC.

Size of the Room- According to manufacturers, a 100-150 sqft room needs a 1.5 ton AC and a 200 Sqft room needs a 2 ton AC. When you use a low-tonnage AC for a larger room, the AC runs at a higher power to cool down the whole place, which too can adversely affect the power consumption.

Latest BEE Rating

Given below is the latest BEE rating with validity from Jan 2022 to Dec 2024. We shall use this data to understand more about the average power consumption of different ACs in the next section.

BEE Rating of Split ACs

Star RatingMin. ISEERMax. ISEER

BEE Rating of Window ACs

Star RatingMin. ISEERMax. ISEER

Calculating Power Consumption of 1.5 Ton Split AC

A quick search on Amazon and we found that among the available options, LG Q19YNZE is a 1.5 ton split ACs with the highest ISEER rating of 5.2. Its annual energy consumption is 685 units. So, the per-hour energy consumption under ideal conditions would be around 0.42 units. The maximum energy consumption of a 1.5-ton 5-star AC with ISEER of 5 would be around 0.48 units.

Similarly, we have calculated the power consumption of a 1.5-ton split AC with different energy ratings as follows. This assumes a cooling capacity of 5000 Watts.

Star RatingMin. Power Consumption
(Per hour)
Max. Power Consumption
(Per hour)

Calculating Power Consumption of 2 Ton Split AC

Here, we assume a cooling capacity of 6000 Watts for the calculation.

Star RatingMin. Power Consumption
(Per hour)
Max. Power Consumption
(Per hour)

Power Consumption of 1 Ton Split AC

Here, we assume a cooling capacity of 3500 Watts for the calculation.

Star RatingMin. Power Consumption
(Per hour)
Max. Power Consumption
(Per hour)

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