Heat pumps are becoming increasingly popular in North America, as they are energy efficient and can provide year-round climate control by supplying heat in the winter and air conditioning during the summer months. Heat pump heating efficiency is commonly defined by the dimensionless unit coefficient of performance (COP), which is the ratio of heat delivered by the heat pump system to the electricity consumed. The efficiency of heat pumps is substantially higher than other types of heating systems like natural gas furnaces or electric baseboards. Heat pumps transfer heat from a source (or sink) including outdoor air, the ground, or a mechanically heated or cooled fluid loop rather than producing it (e.g. via an electric resistance coil or by burning natural gas). In the heating season, heat is extracted from the heat source and supplied to the conditioned space. During the cooling season, heat is extracted from the conditioned space and rejected to the heat sink.

Two common types of heat pumps used for space heating in low-rise residential applications are air-source heat pumps (ASHPs) and ground-source heat pumps (GSHPs). ASHPs absorb heat from the outside air during the heating season and use a refrigeration cycle to transfer that heat indoors. During summer months, they absorb heat from indoor air and reject that heat outdoors. ASHPs are the most common type of heat pump currently installed in Canadian homes. GSHPs transfer heat to and from the ground, which maintains a nearly constant temperature year-round. In British Columbia the ground temperature is generally around 7 to 12°C year-round⁴. Although they are more efficient than ASHPs, GSHPs are also substantially more expensive; as such, they are not widely used.

This guide is focused on ASHPs since they are the most common and most applicable to low-rise residential applications (i.e. single-family homes, townhomes, etc.).