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About the Energy Star Air Conditioners Energy Rating System Print

cooling onlyAir conditioners are among the greatest consumers of electricity of all home appliances. While this is an inescapable fact, it is possible to buy an air conditioner today that is substantially more energy efficient than any air conditioner you could have purchased in the past. By combining the purchase of an air conditioner with a high Energy Star Energy Rating with informed and conscientious use of your air conditioner, you can drastically reduce your energy consumption.

Every brand and model of air conditioner must undergo a strict testing procedure before Energy Star gives it an Energy Rating. Unlike fridges, which cool a relatively small amount of well-insulated space, air conditioners must be able to cool and/or heat large, poorly insulated spaces in a wide variety of environments, ranging from extreme cold to extreme heat. For this reason, Energy Star labels for air conditioners are a little different from the Energy Rating labels on other consumer goods.


Energy Rating Labels

First, there are actually three different labels for air conditioners: one for heating, one for cooling and another combined label for heating and cooling. The only way to make accurate comparisons for reverse cycle air conditioners is to have dual labels, since one brand or model may cool very efficiently as compared to another but heat relatively inefficiently. Naturally, you would choose the model that had the highest Energy Rating for your needs. 

In addition to the Energy Rating Stars across the top of the label, two kilowatt measurements are listed on Energy Star labels for air conditioners. The first is labelled Capacity Output kW, while the second one is labelled Power Input kW. An understandable question that might arise is: How can the Capacity Output be greater than the Power Input? In simple terms, the way that air conditioners cool warm air is through a technique called the Vapour Compression Cycle. This is a very energy efficient system that can move low grade heat three to five times faster than the energy that is used to run the compressor is moved (or consumed). The difference between these two movements of energy is called the Energy Efficiency Ratio (EER) on cooling systems and the Coefficient of Performance (COP) for heating systems. In a nutshell, the two numbers associated with Capacity Output and Power Input are the basis for the Energy Star rating given to air conditioners.

Variable Output Compressorreverse cycle

Another important addition to the Energy Star label on air conditioners is the tick box for Variable Output Compressor. This is a new type of compressor that works very efficiently over time when the unit is operating at mid-power loads but inefficiently when the air conditioner is used only periodically with high bursts of power. Look for a tick in the "Yes" box if you live in a hot area where you are likely to be running your air conditioner constantly. If you only use your air conditioner occasionally, then you will get greater efficiency with a model that does not have this type of compressor.

New vs Old Ratings

When you browse through our catalogue of air conditioners, you will notice that some of them have an old Energy Rating, while others have a new Energy Rating. In 2000, Energy Star introduced more stringent energy efficiency ratings. Those air conditioners that have been rated according to the new system will often have lower Energy Ratings than those that were tested using the old system. The new labelling requirements from Energy Star only came into force in April 2010. Wherever possible, we have listed both ratings on our individual product description pages.