All About Efficiency Ratings

Have you ever checked out your HVAC system and seen a yellow tag with a rating scale on it? This tag displays the efficiency rating of your system, and we're here to explain the simple, reliable methods that are used to create these ratings! 

Efficiency ratings were put in place to inform homeowners and prospective buyers on the efficiency of their heating or cooling system. These ratings are governed by the Department of Energy. They’re based on mathematical equations that often calculate the heating or cooling output by the electricity or gas used.

Below is a list of what each rating means for specific HVAC units, how they're calculated, and what the ratings mean for you as a homeowner. After reading this, we hope that you will feel empowered as a homeowner with all of this information under your belt! Get ready to enjoy the benefits of a reduced energy bill and leave a positive impact on the environment at the same time.



According to Trane, a SEER (Seasonal Energy Efficiency Ratio) rating measures air conditioning and heat pump cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. The standard for SEER ratings runs between 13 at the lowest, to 21 at the highest. Think of the SEER rating as a maximum efficiency rating, similar to the miles per gallon that your car gets in a city versus driving on the highway. Remember, the higher the SEER rating, the greater the air conditioner’s efficiency, thus the more energy it will save.

When comparing two different air conditioner units for use in your home, remember that the unit that has a higher SEER rating will be the more efficient of the two.



AFUE is a number that specifically represents the fuel-efficiency of a furnace and boiler. AFUE accounts for the amount of fuel that is used when the unit works and converts that number into a percentage. If your AFUE number is a 95, then it used 95% of the fuel but lost 5% to exhaust.

Naturally, the higher the AFUE number, the more fuel-efficient your furnace or boiler is. The best furnaces on the market have high AFUE numbers and utilize almost all of their fuel. Next time you’re in the market for a furnace or boiler, be sure to check the AFUE rating!



HSPF stands for Heating Seasonal Performance Factor and is a rating that is used to measure the heating efficiency of heat pumps. HSPF is calculated by dividing the overall heat output by the overall electricity used. HSPF ratings go up to 10, and the closer the rating is to 10, the more energy-efficient the heat pump is, and thus the more money it will save you down the road.

Heat pumps are great units, so if you find yourself in the market for one, make sure you check the HSPF rating!



EER stands for Energy Efficiency Ratio, and it is different from SEER in that it calculates a more rigid form of overall cooling output. Unlike SEER that is based on the seasonal output with a range of outside temperatures, EER is determined by a single outside temperature and a single inside temperature. It doesn’t take into account seasonal change and gives a more general rating.

EER ratings are usually used to rate a window, ductless, or single-room air conditioner because calculating the SEER is impractical for smaller units. So if you find yourself in the market for something small, this is the rating to pay attention to!



IEER stands for Integrated Energy Efficiency Ratio and is most commonly used to rate split-systems. It is another energy rating that is important to know about but is one you might not actually see or hear about as much as the others. The IEER rating evaluates the system's output at different times with specific conditions. IEER helps when evaluating a split-system because split-systems utilize multiple air handlers and work in multiple different conditions.


These numbers are important to pay attention to when owning or buying a heating or cooling unit; they can be the difference between making a good choice and a great one. We believe that a consumer should know what they’re getting into with any kind of purchase, especially with a major investment in the home. Ratings give prospective buyers and current HVAC owners insight into the system. The more you know about your system, the better!

If you have any more questions on home heating and cooling efficiency ratings, please contact us today!