iseer: Explained: ISEER, EER, star ratings and what they mean for your AC, electricity bills and more

Buying an air conditioner (AC) isn’t as easy a task as it used to be a few years. There are a plethora of options available in the market. If that wasn’t confusing enough then should you go for a “5 star” or “3 star” AC? Then there’s the question of whether an inverter AC is better or should you opt for a non-inverter one. The ratings — or star system — remain a key aspect when buying a new AC. You might have seen that yellow sticker that adorns the front of the AC. It’s the sticker that has all the information like how many star ratings it has, what’s the ISEER and how many electricity units will it roughly consume in a year. Here we tell you what are the different types of ratings — ISEER, EER — and what they mean for your AC and electricity consumption.

What is ISEER rating?

It is actually called EER or Energy Efficiency Ratio — a grading system introduced by the Bureau of Energy Efficiency (BEE). The grading system is meant for home appliances — mainly air conditioners and refrigerators. Temperatures can go pretty high in India during the summer season and since air conditioners consume a lot of energy, the BEE came up with a season rating standard called ISEER or Indian Seasonal Energy Efficiency Ratio.

How are ISEER ratings calculated and how does it work?

Alright, so let’s get into some more abbreviations. ISEER is actually the ratio of CSTL (Cooling Seasonal Total Load) to CSEC (Cooling Seasonal Energy Consumption). In simple words, this is the ratio of the annual amount of heat the AC can remove to the total amount of energy it can consume in a year. The energy efficiency of any AC is calculated on the average performance based on temperatures — outdoor — between 24 degrees to 43 degrees celsius.

Yes, EER — Energy Efficiency Ratio — also matters as it is the amount of heat an AC removes in an hour divided by the total power it consumed during that time. The difference between ISEER and EER is that the former is meant for a season — so the word seasonal is prefixed before it.

Do the EER and ISEER have an impact on power consumption?

Yes, it certainly does. The higher the ISEER value, the more is the efficiency of the air conditioner. The same is true for EER. The higher the EER value, the more energy-efficient the AC will be.

Do ACs with higher EER and ISEER cost more?

Yes, they do end up costing more. It’s like how 5-star Acs are expensive because they have better ratings. So they will end up costing more but could help in saving more money on your monthly power bills.

Important things to keep in mind:

ISEER ratings for Window and Split AC (as per BEE)