In North Texas, we are blessed with relatively mild winters until all of a sudden—we aren’t. The extreme weather we’ve all experienced recently is a good example of the exception to the rule. When extreme weather like this occurs, questions always arise about the way heat pump systems operate, so let’s take a few moments to discuss how heat pumps do their job.
Heat pumps are really reversible air conditioning systems. In the summer, a heat pump removes the heat from inside your house and sends it outside. In the winter, it reverses that process and gathers heat from outside your home, and sends it inside. A heat pump is a tremendously cost-effective way to heat and cool your home. However, in the winter temperatures need to be above 25 to 30 degrees for it to do its job. In Texas, that’s almost always the case.
That “almost” means there are times when the temperatures are lower than normal, and your heat pump cannot operate normally either. Since that may happen occasionally, it’s always good to have another plan. All heat pumps have a backup source of heat. Either they have electric elements in an air handler or a gas furnace to produce heat. Therefore, when the temperature falls below 25 degrees, the backup heat source takes over. The lower the temperature, the more backup heat is active and warming your home. If your backup uses electricity, it will come on gradually to supply the heat you need. If you’re using a gas furnace, the heat pump completely turns off, and the gas furnace takes over.
In these extreme temperatures, an all-electric heating system will cost more to operate. If you’re using natural gas or propane to heat your home, you’ll use more of those products as well. Basically, that means your bills are going to be higher than normal. That’s why having a heat pump is still a far better and more efficient system than a straight electric furnace or gas furnace since it will save you money when our normally mild winter temperatures are going on.
Heat pumps also have a defrost cycle. Since refrigerant is much colder than the outside air, heat pump coils form ice on the outside coil. This ice should never be more than a quarter-inch to 3/8 inches deep. Your heat pump has a sensor or a timer that activates the defrost cycle. When that happens, the heat pump goes into air conditioning mode and pumps hot refrigerant into the outside unit. Your backup heat comes on to keep you comfortable while the heat from the refrigerant melts the ice. When that happens, it’s perfectly normal for steam to issue from the outside unit. The fan may also not run while the defrost cycle is going on.
The bottom line is that heat pumps are a tremendously efficient way to heat and cool your home. They are well worth the quirks in their operation.
As always, if you have any questions, please reach out to us.
We’re always happy to help!