Heat Pump 

Heat Pump Systems  Your home’s heating system may be either a gas or electric furnace, or a heat pump system with backup heat provided by a gas or electric furnace. The easiest way to find out if you have a heat pump is to look at the thermostat. If your thermostat has a switch that can be set only to “heat” or“ cool”, then you do not have a heat pump. However, if the switch also has a position for “emergency heat”, then you have a heat pump. You may also see a light for “auxiliary heat” – this also means you have a heat pump. A heat pump uses electricity to make heat, but much more efficiently than an electric furnace with heating elements. It uses the same components as the air conditioning system. In fact, it is running the air conditioning system in reverse. The refrigerant in the system flows in the opposite direction, the condensing coil becomes the evaporating coil, and the evaporating coil becomes the condensing coil. When in air conditioning mode, heat is removed from the inside air and taken outside; in heat pump mode heat is taken from the outside air and moved inside. Even when it is cold outside, the outside air still has enough heat that can be extracted by the heat pump and used to heat your home. However, when it gets really cold, say into the low 20’s, the air coming into the home may be just a few degrees warmer than the inside temperature. This may cause the home to feel drafty, or less comfortable. This is why a heat pump system has “auxiliary” or “emergency” heat. This backup heat is provided by a conventional gas or electric furnace. Emergency heat can also be used if the heat pump system stops working for some reason. There is a sensor at the outside heat pump unit that determines the outside temperature. The system will automatically switch to auxiliary heat when the temperature falls below a pre-set temperature. A heating and air conditioning contractor can adjust this temperature. The system will also switch to auxiliary heat if the inside thermostat is set several degrees above the inside temperature, or if the switch is set to emergency heat. So, auxiliary heat will usually come on automatically if it gets too cold outside, or if the heat pump can’t keep it warm enough inside. If your backup heat is electric resistance heat instead of gas, heat pump mode will almost always be more efficient. However, a gas furnace is often more efficient than a heat pump at lower temperatures. Heating your home with gas when it is very cold outside can save money, and using the heat pump when it is cool outside can prolong the life of your gas furnace. After some experience with the heat pump system in your home, you can have the thermostat set to automatically switch to the mode that keeps you most comfortable with the most efficiency. [ Back to General Home Information ] Schedule Your Inspection Today