Heat Pump Basics

   If you live in a warmer climate, you may use what is called a "heat pump" to control the temperature in your home.  Heat pumps are different from conventional heating and air conditioning units in that heat pumps have the ability to heat and cool in one unit.
    Traditionally, homes contained a heating unit that generated heat from electricity or the combustion of a hydrocarbon fuel.  In addition to the heating unit, another unit was needed to cool the air inside homes during the summer months. Heat pumps are able to achieve both by a very simple concept, moving heat.
    Heat pumps work best in climates where the ground or water temperature is not expected to drop below 45 ⁰F for extended periods of time.  If this is expected, a supplemental, electric heat source is usually included in the unit.

    The concept is simple really.  During the heating season (when the ground/water temperature is greater than the air temperature), a liquid refrigerant flows into the coils underground or underwater and absorbs heat.  The heat from the ground/water vaporizes the low boiling refrigerant to a gas.  The gas is compressed to a hotter gas reaching temperatures up to 200 ⁰F.  This heat is then transferred to an air handler to heat your home.
    During the cooling season, the cycle is simply reversed.  The cold liquid refrigerant is circulated through the air handler where it absorbs and removes the unwanted heat from the air and vaporizes the refrigerant to a gas.  The gas is compressed to increase its temperature and then the underground/underwater coils act as a condenser rather than an evaporator (as in the heating cycle).  The heat in the refrigerant is transferred to the ground/water as the refrigerant condenses.