Similar to an air conditioner but can operate in reverse to heat as well as cool. Transfers heat (usually from the air) from one location to another.
A HVAC unit that heats and cools by transferring heat. In cold weather a heat pump draws heat from outside and circulates it through your home's air ducts. In warm weather it reverses the process and removes heat from your house and moves it outdoors.
A mechanical device used for heating and cooling which operates by pumping heat from a cooler to a warmer location. Heat pumps can extract heat from air, water, or the earth. They are classified as either air-source or geothermal units.