A heat pump is a device that extracts heat from the air in one place and transfers it to the air of another place. In the context of heating and air conditioning, a heat pump is an electric powered all-in-one heating and cooling device that operates using the same basic technology as an air conditioner.
A refrigerant circulates through the heat pump absorbing, transferring, and releasing heat. In the summer, heat is transferred from the interior of a house to the outside. In the winter, heat is transferred from outdoor air to the inside of the house, counterintuitive as that may sound. A heat pump even looks a lot like a conventional air conditioner.
While common in the southern United States, heat pumps have not generally been considered viable for home heating in Wisconsin. When outside air temperatures fall below freezing, there is insufficient heat to transfer to the indoor air of a home.
However, heat pumps are becoming more popular in rural Wisconsin for supplemental heat. In areas that lack access to natural gas service, most furnaces are powered by fuel oil or liquid propane (L.P. gas). As the cost of these fuels has soared, many homeowners have found that adding a heat pump can be a cost effective solution to reduce fuel use when temperatures are cold, but above freezing.
In addition, these homeowners realize cost savings on their summertime cooling bills because heat pumps operate more efficiently in their cooling mode than conventional air conditioners.
As with all technologies, there are trade-offs. Preventative maintenance costs are higher than for conventional furnaces and air conditioners. The outside units are large and must be mounted on special stands.