Understanding the Terminology


HVAC equipment has its own terminology which sometimes confuses a consumer. Anyone looking to buy air-conditioning units Phoenix or heat pumps gets a little confused and don’t always understand the importance of certain acronyms. Knowing what the special terms mean can help in making a buying decision.


The Seasonal Energy Efficiency Ratio (SEER) is used to measure the efficiency of an air conditioner unit. It is the measure of the cooling output that happens during a cooling season and is divided by the total electrical energy output of the same time. In the United States that would be the ratio of the British thermal unit (BTU) to the watt hours of energy which are consumed. Plainly spoken, this ratio gives a picture of the amount of energy required to create a certain level of cooling output. The lowest SEER permitted commercially is 13, and the higher the rating will mean the more efficient energy-wise the air-conditioning unit happens to be.

Energy Efficiency Ratio (EER) is the ratio of BTU to watt hours of energy consumed. Like the SEER, the efficiency of an air conditioner is greater if the rating is higher. The standard for air conditioner units sold United States is a range of 8.0-9.8 or more.

Heating Seasonal Performance Factor (HSPF) measures the energy efficiency over one heating season of heat pumps. It is the ratio of BTU to watt hours during the given period. The industry standard is that heat pumps must have a rating of no less than 6.8.


The efficiency of an ENERGY STAR product can be better understood given these industry standards mentioned above.

For an air source heat pump to be used for a split system, ENERGY STAR requires the following: SEER, no less than 14.5; EER, no less than12; HSPF, no less than 8.2 ratings.

Central air conditioners to be used for split systems: SEER, no less than14.5; EER, no less than a 12 rating.

Single package equipment have slightly less rating requirements, but it is obvious that ENERGY STAR insists on a higher than normal ratings as far as efficiency is concerned. This means that while the product may be a bit more expensive, the energy efficiency is at the top end of the spectrum.

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