Heat Pump Glossary
Plain-language definitions of heat pump and home electrification terms, explained the way a Jetson expert would.
AHRI Certificate
An AHRI certificate is independent, third-party verification of a heat pump system's published efficiency ratings for a specific equipment combination.
Backup (Auxiliary) Heat
Backup or auxiliary heat is supplemental electric resistance heating that some heat pump installs add to cover the coldest hours, though a properly sized cold-climate system often never needs it.
Cold-Climate Heat Pump
A cold-climate heat pump is engineered to heat a home efficiently in sub-freezing temperatures, often down to around -22°F, without relying on backup heat.
COP (Coefficient of Performance)
COP is the ratio of heat a heat pump delivers to the electricity it consumes. A COP of 3 means three units of heat for every unit of power, or about 300% efficiency.
Dual Fuel (Hybrid Heat)
Dual fuel, or hybrid heat, pairs a heat pump with a gas or oil furnace that takes over in the coldest weather, so the home switches between electric and fossil heat.
Ductless Mini-Split
A ductless mini-split is a heat pump that delivers heating and cooling through wall- or ceiling-mounted indoor units instead of ductwork, used mainly in homes without existing ducts.
HSPF2
HSPF2 is the current industry rating for a heat pump's heating efficiency over a season. A higher number means more heat delivered per unit of electricity.
Manual J / Heat-Loss Calculation
Manual J is the standard method for calculating how much heating and cooling a home needs, used to size a heat pump or furnace correctly.
SEER2
SEER2 is the current industry rating for a heat pump's cooling efficiency over a season. The higher the number, the less electricity it uses to cool your home.
Static Pressure
Static pressure is the resistance air meets as it moves through your ducts. Too high, and the system works harder, runs louder, and loses efficiency.
Variable-Speed (Inverter) Compressor
A variable-speed (inverter) compressor ramps a heat pump's output up and down to match the home's exact need, instead of switching fully on and off like older single-speed units.