Cold weather geothermal heating is a real concern for some homeowners. After all, if you live in a northern climate with severe winter weather, can you depend on a geothermal heat pump to keep you warm all winter long?
Cold Weather Geothermal Works
An air-source heat pump can do double duty cooling in summer and providing warm air during much cooler weather. The downside is that, as the temperature drops, so does the energy efficiency of an air-source heat pump. If it gets cold enough, an air-source heat pump will become ineffective and some other type of heat supply will be required. In such a situation, most homeowners who use an air-source heat pump have an electric heat kit or gas furnace as a backup for the very coldest winter days.
Geothermal heat pumps do not suffer from this problem. An air-source heat pump starts to suffer inefficiencies, because it uses the external air as a source from which to draw heat to put back into the house. Of course, the more the temperature drops, the less heat there is outside and the harder the air-source system has to work. A geothermal heat pump’s subsurface source rarely fluctuates in temperature no matter how hot or cold it is above ground and that allows a geothermal heat pump access to stable environment all year round.
Of course, we can also turn to empirical data showing how effective geothermal heat pumps are in cold weather climates. Geothermal heat pumps are very popular in Sweden and Norway in hydronic heating applications. Most places in the United States don’t have winters comparable to Scandinavia. If a geothermal heat pump works well in the icy lands north of the Baltic, they will work anywhere in the Continental US.