Everything you should know about ISEER, EER, BEE Star Ratings in an AC

Last Updated on 26 February, 2023 by Darshan Chana

ISEER, EER, BEE Star Ratings – don’t these jargons ring a bell? The Energy Department has given most home appliances star ratings. The ones mentioned above certainly describe the efficiency of air conditioners. As much as important they are, these terms can certainly be confusing to any commoner.

ISEER, EER, BEE Star Ratings in an AC


With very limited knowledge about the appliance, I have noticed people bringing home an air conditioner. Leave aside the brand, the look appeal, the features; there’s more to it. I would like you to think big. Each star rating defines the cooling competency of an air conditioner.

So, let’s begin with knowing what each term stands for and how it is calculated. Oh well, it may sound technical, but it isn’t. You believe me, right?


1. What is ISEER?

ISEER Rating

ISEER, also known as the Indian Seasonal Energy Efficiency ratio, is the actual amount of heat an air conditioner can eliminate from the indoor air (annually) to the actual amount of power consumed by the air conditioner in the same period. The Bureau of Energy Efficiency made the ISEER rating mandatory in the year 2018.

ISEER is calculated as follows:


CSTL refers to the cooling seasonal total load.

CSEC refers to the cooling seasonal energy consumption.

This ratio differs completely in a split and window air conditioner.

ISEER Ratings of Window Air Conditioner

Star LevelMinimumMaximum
1 star2.502.69
2 star2.703.89
3 star2.903.09
4 star3.103.29
5 star3.30-

ISEER Ratings of Split Air Conditioner

Star LevelMinimumMaximum
1 star3.103.29
2 star3.303.49
3 star3.503.99
4 star4.00 4.49
5 star4.50-

What are the benefits of high ISEER rated Air Conditioners?

  • These appliances are eco friendly.
  • High ISEER rated air conditioners assure high utility bills.
  • They can eradicate moisture from the air.
  • These air conditioners can control humidity to a great extent.


2. What is EER?



EER, also known as the Energy Efficiency Ratio, defines the amount of heat that can be eradicated by an air conditioner every hour and is divided by the energy consumed to do so. The higher the EER, the more the efficiency of the appliance.

EER is calculated as follows:

EER = BTU/hr/Watt

BTU refers to the cooling capacity.

Watt refers to the power input.

Let me give you an example to explain you further. Considering an air conditioner of 10,000 BTU consumes 1,200 watts. Going by the calculation, the EER of the appliance will be 8.3.

The Energy Department has stated that the accepted norm of an EER as 27 degrees for inside the room and 35 degrees for outside the room.

What are the benefits of high EER rated Air Conditioners?

  • High EER rated air conditioners can really help save money and energy in the long run for working spaces that have long-running hours of Air Conditioners like Corporate offices, business sectors, industries and more.
  • Air conditioners with high EER have better cooling technologies.
  • These appliances have a low lifecycle cost.


3. What is BEE Star Ratings?

What is BEE Star Ratings

Every air conditioner comes with a BEE star rating label to it which explains its efficiency. The meaning of it is simple. ACs are rated on a scale of 1-5. The lesser the rating, the more energy the appliance consumes. Air conditioners with a star rating of 5 are considered to be the most energy-efficient. However, 5-star air conditioners are certainly more expensive than 4, 3 or 2 star AC. Well, in that case investing in a 4 star AC would also be a smart move. It will be cheaper than a 5 star one and more energy-efficient than a 3 star one.

The calculation of BEE is pretty simple. The value of ISEER or EER calculates it. Higher the value of the two means a high BEE star rating of the air conditioner. High BEE vale clearly means more energy savings.

The government has made it mandatory for most home appliances to have a BEE star rating, not just the best air conditioners. For instance, the best washing machines, best refrigerators, best microwave ovens and more have a 5-star BEE rating.

Over the years, BEE has made the star ratings more stringent. For example, an air conditioner that has been given five stars in the year 2018 will not qualify even one star in the year 2023.

Why is a 5-star air conditioner better than a 1 star? Simple because of the power consumption. Let me brief you on the power consumption of both inverter and non-inverter for different star rated air conditioners.

AC type Non Inverter/Inverter0.75 Ton1 Ton1.5 Ton2 Ton
3 Star Non-inverter62782812351548
3 Star Inverter55072610771344
5 Star Non-inverter57676011301412
5 Star Inverter4215578151005

What are the benefits of high BEE rated Air Conditioners?

  • Higher the star rating, the more energy-efficient the air conditioner.
  • High BEE rated air conditioners assure better cooling.
  • These appliances are also eco friendly.


Barring the ISEER, EER, BEE Star Ratings, there are more aspects you can look into

1. COP

COP is popularly known as the Coefficient of Performance. It is an efficiency measurement of an air conditioner’s heat pump. The higher the COP, the lower the operating cost, the better it is. COP measures the heating performance of the air conditioner. Hence it is important to look into this aspect as well before making a purchase. There is a correlation between EER and COP.

EER = COP * 3.412



HSPF stands for heat seasonal performance factor. This means that the higher the HCPF, the more efficient the unit is. Technically, HSPF is the total heat output from the air conditioner. HSPF is simply calculated by taking the total heating required in BTUs, and it is then divided by the total energy consumed in the same period.



CSEC stands for the Cooling Seasonal Energy Consumption. It indicated the total amount of energy consumed by the air conditioner while it is functioning.


One Last Thought

ISEER, EER, BEE Star Ratings, you know everything about each one of them. How it is calculated, and how inevitable it is. One thing is for sure; no tall promises can confuse anymore.

Before we say goodbye, I would like you to know that BEE star ratings change every two years. So, be sure of getting yourself updated. The more stars, the more the air conditioner will cost you. However, in the long run, it is only going to benefit you.

My only motive behind doing this blog was to unload you from the big strains of electricity.

PS: An air conditioner with a higher rate of all jargon should be your pick.

Follow me

Leave a Comment