The question arises from time to time in building industry blogs about whether or not geothermal heat pumps (GHPs) are a source of renewable energy. GHPs don’t fit neatly into any box, but suffice it to say that their appeal is for their efficiency and the abundant renewable energy that they provide.
GHPs use the ground as a moderate-temperature heat source during the winter and a heat sink during the summer. They draw renewable (yes, renewable) thermal energy from the ground during the winter to heat buildings, and reject heat from buildings back into the ground in summer, thus replenishing the heat drawn from the ground during the previous season.