Two new “words” that you may come across today in your search for a new HVAC unit are the acronyms EER and SEER. EER stands for Energy Efficiency Rating, while SEER stands for Seasonal Energy Efficiency Rating. Both are of equal importance, but you also have to know in which context to use them.
The Energy Efficiency Rating was introduced over forty years ago, in 1975, and was used as a means for engineers and technicians to gain a complete grasp of the energy efficiency of all the different makes and models of HVAC units. In order to create a ‘benchmark’ against which all readings and ratings could be measured, all EERs are based on a unit operating at an outside temperature of 95 degrees, indoors temperature of 85 degrees, and 50% humidity.
EERs are becoming less important these days, so are not always so easy to find. Their main used would be for comparing ‘like-for-like’ models from different brands.
The Seasonal Energy Efficiency Rating is a more up-to-date energy rating system. This rating is based on the operating performance of an HVAC unit over an entire cooling season. The total cooling output is divided by the amount of energy used, thus enabling you to get a fuller picture of just how well your unit will perform during the hottest months.
The benchmark figure for the SEER is 13, and your unit should have a rating of a minimum of this. Typically, HVAC units installed prior to 2006 are unlikely to meet the level 13 requirement. As an example, if you have a very old unit which has a SEER rating of just 6, and you replaced this with a new unit which has a SEER rating of 13, you could cut your HVAC running costs in half!
It is important to remember that you should only compare like for like, in other words SEER ratings against SEER ratings, and EER ratings against EER ratings.