Equipment
Heat Pump
Heating and cooling equipment that uses a refrigeration cycle to move heat between locations.
What is Heat Pump?
A heat pump moves heat rather than creating all of its heating output directly from fuel combustion or electric resistance. In cooling mode it transfers heat from indoors to outdoors. In heating mode, a reversible heat pump transfers heat from an outdoor source into the conditioned space.
Common heat-pump categories include air-source, ductless mini-split, and ground-source systems. Many air-source heat pumps use a reversing valve so the same refrigeration circuit can provide both cooling and heating.
Heat-pump capacity and efficiency change with operating conditions. Cold-climate performance, defrost behavior, backup heat, and the equipment's low-temperature capacity can matter as much as its headline seasonal efficiency rating.
Why it matters
Understanding that a heat pump transfers heat makes ratings such as COP and HSPF2 easier to interpret and helps explain why heat pumps can provide efficient electric heating.
Sources
HVACBird prioritizes government standards bodies, federal test procedures, and recognized HVAC certification organizations for technical definitions.
U.S. Department of Energy
DOE overview of heat-pump operation, ductless systems, and variable-speed/inverter technology.
Related HVAC Terms
COP
A dimensionless ratio comparing useful heating or cooling delivered with the work supplied to the system.
HSPF2
A seasonal heating-efficiency rating for air-source heat pumps.
SEER2
A seasonal cooling-efficiency rating used for central air conditioners and heat pumps.
Inverter Compressor
A compressor drive system that can vary compressor speed and capacity instead of operating only fully on or fully off.