Although temperatures in the atmosphere can vary considerably over the course of a year (or even a day), the temperature underground remains fairly constant. At about six feet under, the soil measures from 45 degrees to 75 degrees fahrenheit, depending upon latitude. And this consistency, it turns out, can be a resource for keeping one's home warm in the winter and cool in the summer.
In winter, ground source heat pump transfer heat from the earth into building to heat up the rooms. In summer, the ground source heat pump transfer heat from building into the earth to keep the rooms cool.
