Heat pumps are known for being energy efficient. Some of them, in fact, are up to 300% efficient when in heating mode, meaning they can produce three times as much heat as the energy they consume. But heat pumps don’t use the same efficiency metrics as furnaces. While the furnace efficiency is often measured in Annual Fuel Utilization Efficiency (AFUE) ratio, heat pump efficiency is often measured in Heating Seasonal Performance Factor2 (HSPF2).
What Is HSPF?
HSPF is a measurement of a heat pump’s efficiency. It represents the ratio of a heat pump’s output – as measured in British Thermal Units (BTUs) – relative to the heat pump’s consumed electricity during a typical heating season.
Heat pumps with a high HSPF ratio are more efficient than those with a low HSPF ratio. The U.S. Department of Energy (DOE) regularly evaluates its efficiency specifications. In a recent evaluation, the DOE identified ways to improve the HSPF specification. This led to the creation of the HSPF2 standard, which uses a refined formula to calculate the efficiency of heat pumps.
What Is HSPF2?
HSPF2 is the successor to the HSPF specification. As previously mentioned, it uses a different and modified formula to determine the efficiency of heat pumps.
HSPF2 is still based on the heating output of a heat pump relative to its consumed electricity, but the DOE now requires different testing for HSPF2. Nonetheless, a high HSPF2 ratio indicates an energy-efficient heat pump. A low HSPF2 ratio, on the other hand, indicates a lower level of heating efficiency for heat pumps.
Why Choose a High-HSPF2 Heat Pump
Why should you choose a heat pump with a high HSPF2 ratio exactly? The DOE requires all new heat pump systems to conform to this specification. All split-system heat pumps must have an HSPF2 ratio of at least 7.5, and all packaged heat pumps must have an HSPF2 ratio of at least 6.7.
A high HSPF2 ratio can save you money on your home’s heating costs. By choosing a heat pump with a high HSPF2 ratio, you’ll experience cost-savings benefits in the form of lower utility bills. It will warm your home by transferring heat from the outdoors to your home’s interior.
The HSPF2 specification is less forgiving than its predecessor, the HSPF specification. It involves harsher testing conditions. With these harsher testing conditions, HSPF2 offers a clearer and more accurate representation of a heat pump’s efficiency.