How a Heat Pump works
A heat pump is simply an air conditioner that is also used in the heating season. In cooling it works no different than a regular air conditioner but in heating the hot & cold air is reversed. Most everyone is familiar with the original window air conditioning unit. It blows cold air inside the house while blowing hot air outside. Imagine taking it out of the window in the winter time & turning it around. Now the hot air that was blowing outside would then blow inside the house. A heat pump is actually designed to do just that internally with the addition of a reversing valve. There are some other features like a defrost system added to keep it from freezing up in certain weather conditions but the basic concept is just an air conditioner in reverse during the heating season.