Refrigerant
The fluid that circulates through a heat pump, absorbing and releasing heat as it changes between liquid and gas states. Modern systems use R-410A or the newer, lower-GWP R-32 and R-454B.
Why It Matters
The refrigerant transition from R-410A to lower-GWP alternatives (R-32, R-454B) is underway due to AIM Act regulations. New equipment purchased after 2025 increasingly uses these newer refrigerants.
Related Terms
Heat Pump
An efficient HVAC system that transfers heat rather than generating it, providing both heating and cooling. Air-source heat pumps are most common; ground-source (geothermal) are most efficient.
COP (Coefficient of Performance)
The ratio of heating or cooling output to electrical energy input for a heat pump. A COP of 3.0 means the system produces 3 kWh of heat for every 1 kWh of electricity consumed.