Energy Ratings in Air Conditioners – Explained

Energy Ratings in Air Conditioners – Explained

Energy Ratings in Air Conditioners – Explained – Energy Rating (BEE, ISEER and EER) of an Air Conditioner is probably the first thing most people look for when purchasing one (after they have decided what tonnage capacity they need of course). But there are still so many people who don’t know what these numbers really mean (besides the well obvious fact that 5 Stars is better than 1 Star). Well, the short answer to that is these Energy Ratings signify the amount of electricity you’ll save as compared to the least energy-efficient [1 Star] AC on the market. In this article, we’ll explain all the different Energy Ratings (BEE, ISEER and EER) that are used to evaluate the energy efficiency of AC(s) in India and how they affect you as a consumer.

Different Energy Ratings used in ACs

BEE Star Rating in ACs

‘BEE’ in BEE Star Rating stands for the Bureau of Energy Efficiency. The Bureau of Energy Efficiency is an agency of the Government of India created to develop programmes which will increase the conservation and efficient use of energy in India. Since January 2010, this agency made it compulsory for certain appliances in India to have their approved rating thus called the BEE Star Rating. The BEE Star Rating is a simple grading system which uses five stars to evaluate the energy efficiency of an appliance (1 Star being the lowest energy efficiency and 5 Stars being the highest). Now, higher the stars of an AC the more it costs upfront – but in the long run, a 5 Star AC will provide a much higher return of investment than say a 3 Star AC. To understand how exactly the Stars are calculated we first need to understand the other two Energy Ratings (ISEER and EER) and how these are all co-related in terms of total power savings per month.

BEE Star Rating and the Corresponding Savings/Month*

1 Star2 Star3 Star4 Star5 Star

*the above numbers are assuming you run your AC for 8 hours per day.

ISEER, SEER and EER Values in ACs

‘ISEER’ in ISEER Value stands for Indian Seasonal Energy Efficiency Ratio and ‘EER’ in EER Value stands for Energy Efficiency Ratio. As for ‘SEER’, you can guess. Anyway, time for a history lesson. The oldest value out of these three is the ‘EER’ or the ‘Energy Efficiency Ratio’ which was used worldwide to assess the energy efficiency of Air Conditioners. The EER of Air Conditioners was calculated using this formula –

EER = Output Wattage (or Cooling Capacity) ÷ Input Wattage.
EER = the amount of heat removed in an hour ÷ power consumed in the same hour.

The problem with this formulation was that it doesn’t take into consideration the temperature change in the concerned room throughout the year which changes the foremost parameter – the amount of heat removed. Even the parameter of power consumed in an hour became irregular with the introduction of variable speed inverter ACs to the world. Therefore, a different standard was introduced called ‘SEER’ which takes into account the seasonal changes in temperature throughout the year. But what the BEE realized is that the climate profile of India varies vastly from the other countries around the globe. So, BEE introduced their own version of ‘SEER’ called the ‘ISEER’ or ‘Indian Seasonal Energy Efficiency Ratio’. The ISEER value of Air Conditioners in India was calculated using this formula –

ISEER = Cooling Seasonal Total Load (CSTL) ÷ Cooling Seasonal Energy Consumption (CSEC).

In general, the higher the ISEER value of an AC is, the more Stars BEE will give to that Air Conditioner. Two different ACs can have the same BEE Star Rating but have different ISEER values. In such cases, we always recommend buying the AC with a higher ISEER value. Another thing to remember is that Split ACs always have an ISEER value higher than that of Window ACs.

And that’s a wrap! Hope you liked our article. If you have any further queries you can ask them below in the comments or you can contact us via email. See you next time!

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