4. What is a heat pump and how does it work?

The heat pump cycle is fully reversible, and heat pumps can provide year-round climate control for your home-heating in winter and cooling and dehumidifying in summer. Since the ground and air outside always contain some heat, a heat pump can supply warmth to a house even on cold winter days. In fact, air at 18°C contains about 85% of the heat it contained at 21°C.