What You Should Know about ISEER, EER, and BEE Star Ratings

People continuously work to make life easier. For years, we’ve used our resources to promote convenience in our homes, schools, and workplaces. Air conditioners, for example, are only one of the many things that make life more comfortable. However, buying air conditioners can be intimidating to people who are not familiar with what specs to look for. For that, this article will help clarify some air conditioner jargon. It will help you prepare when you go into the store and talk with someone about getting the air conditioning unit you’re looking for.

What Is the BEE Star Rating System?

The BEE star rating system is what consumers must look for when buying huge appliances like air conditioners and refrigerators. BEE means Bureau of Energy Efficiency, a bureau in India whose main purpose is energy conservation, and they do this by raising public awareness on energy efficiency. Appliances are given BEE star ratings to let consumers know how energy-efficient they are. The rating ranges from 1 to 5 stars. The higher the star rating an appliance has, the less electricity it consumes to effectively perform its job and the more you save on electricity bills.

The bureau was founded in 2002, and the star rating for air conditioner brands started in 2006. All this is done by BEE to enhance customers’ choice of appliances and minimize energy consumption in a country. This also encourages brands to manufacture more energy-saving products. BEE star ratings are determined by energy efficiency values. This is where the EER and ISEER values come in. But before we go there, there’s one more concept we need to know first. In understanding energy efficiency, it helps to know what BTU is.

BTU stands for British Thermal Unit, a unit used for measuring energy produced from heat. A single BTU is equal to the energy that’s needed to increase one pound of water’s temperature by one degree Fahrenheit. This unit of measurement tells you a heating system’s capacity. But we’re talking about cooling a room; that’s what air conditioners do. How do BTUs apply then?

Air conditioners work not by adding cool air into a room but by removing heat from it. This is done by the compressor system which uses a chemical refrigerant or coolant (usually freons) to absorb heat from the room and release it outdoors.  In this case, BTUs are used as a measurement of how much energy it takes for an air conditioning unit to remove the heat. In other words, BTUs can tell you the cooling capacity of your air conditioner. Let’s talk about energy efficiency.

What is EER?

In an air conditioner or AC, Energy Efficiency Ratio or EER tells how much heat is removed per hour per energy (measured in Watts) consumed within that same hour:


In other words, if an AC has a high Energy Efficiency Ratio, it removes a higher amount of heat per unit measure of electricity it consumes. This ratio is given to ACs with fixed speed compressors (non-inverter). Therefore, as a consumer, you should choose an AC with a higher EER to conserve more energy.

What is ISEER?

ISEER stands for Indian Seasonal Energy Efficiency Ratio. Its value is calculated using the Cooling Seasonal Total Load and Cooling Seasonal Energy Consumption. If you get the keywords “cooling load” and “energy consumption”, it becomes apparent that it’s similar to EER; it just considers seasonal temperature fluctuations and variable power consumption by inverter ACs.  You see, when the variable speed air compressor conditioners or inverter ACs were introduced, the existing energy efficiency calculation methods were not enough. The BEE then introduced an alternative system of value calculation, the ISEER, to close the gap.

What’s the difference between EER and ISEER?

It’s probably obvious now: the EER value is for non-inverter or fixed speed compressor air conditioners while the ISEER value is for inverters or variable speed air compressor air conditioners. Since these values tell us how energy-efficient an AC is, they are the basis of BEE ratings. Higher BEE star ratings translate to lesser energy consumption which means bigger savings.

Using BEE star rating as a basis for purchase, however, is only advised when choosing among the same type of air conditioners. Different types of ACs with different EER or ISEER values can be rated the same by the BEE. For instance, a 4-star rated split air conditioner is still more efficient than a window air conditioner that is also 4-star rated. Therefore, when you compare different types of air conditioners, look at the EER/ISEER values instead of the BEE star rating.

Wrapping it up

The Bureau of Energy Efficiency (BEE) uses a “1 to 5” star rating system to signify how energy-efficient appliances are to help consumers conserve energy and challenge brands to manufacture better products. BEE star ratings are based on the Energy Efficiency Ratio (EER) of non-inverter ACs and the Indian Seasonal Energy Efficiency Ratio (ISEER) of inverter ACs. When choosing among ACs of the same type, choose one with the higher BEE star rating. When choosing among ACs of different types, choose the one with higher EER or ISEER value. The BEE star rating is negligible in this case because different types of ACs given the same star rating by BEE can have different EER or ISEER values.  That’s about it!  We hope we’ve been helpful. Best of luck in scouring the stores for the best AC for you.

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