Before You Buy Know These HVAC System Terms: AFUE, SEER, and HSPF

Before You Buy Know These HVAC System Terms: AFUE, SEER, and HSPFWhat do all those acronyms mean and why does terminology matter when you’re thinking of making an HVAC (Heating, Ventilation and Air Conditioning) purchase? The short answer is that these terms have a great deal to do with rating efficiency of the products — including air conditioners, furnace, and heat pumps — that are essential for home comfort.

With energy costs rising all the time, it just makes good sense to buy the most efficient heating or cooling appliance that you possibly can for use in your home. If you are not a well-informed buyer, you could be throwing money out the window.


AFUE stands for Annual Fuel Utilization Efficiency, and it measures how much fuel is converted into heat in gas-fueled furnaces or boilers. The U.S. Department of Energy requires that new residential gas furnaces have at least a 78 percent AFUE, meaning 22 percent of fuel is wasted. To achieve the Energy Star mark of energy efficiency excellence, furnaces sold in the Northern states (including Missouri and Kansas) must have a minimum AFUE of 95 percent. In the South, the minimum is 90 percent.


Seasonal Energy Efficiency Ratio is a measurement of how efficiently your air conditioner or heat pump provides cooling during a season. The higher the SEER rating, the more efficiently your air conditioner or heat pump turns electricity into cooling. Central split-system air conditioners must have a minimum SEER rating of 13. Energy Star-compliant models start at SEER 14.


The Heating Seasonal Performance Factor measures the heating efficiency of heat pumps. It represents an equation using the heat pump’s expected seasonal heating output (measured in BTUs), divided by the amount of energy it uses for the same period (measured in watt-hours). When buying a heat pump, you’ll want to pay more attention to HSPF if you pay more for heating your home than cooling it. The federal minimum HSPF is 6.8, with Energy Star-certified heat pumps starting at 8.

Contact Us

Since 1983, Overland Park Heating & Cooling Inc. has been serving greater Kansas City-area communities, including Johnson County and Overland Park. Contact us to discuss your HVAC and other home comfort issues.

Our goal is to help educate our customers in Overland Park, Kansas about energy and home comfort issues (specific to HVAC systems). 

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