What to do if your heat pump freezes up

Heating and cooling a home all year long is expensive. Fortunately, an array of options is available to homeowners to cut costs and keep their families ensconced in comfy temps. One of these choices is an electric heat pump, an all-in-one system that efficiently manages a home’s heating and air conditioning needs. Unlike a traditional furnace, heat pumps do not produce heat “from scratch;” instead, they transfer it from inside to outside, or the reverse depending on the season. Here’s how they work:

During warm months, a heat pump soaks up heat from inside a home and moves it outside, thus cooling the house. In winter, the process reverses—heat from outside air is collected and transferred indoors. That might seem counterintuitive but even very cold air includes heat and a heat pump leverages that natural occurrence to keep you warm and cozy. But what happens when it’s really cold and the heat pump freezes up?

Causes of heat pump freeze-up

A range of scenarios can result in a frozen heat pump. One of the most common is restricted air flow. All manner of debris such as dirt, leaves, encroaching foliage or snow can clog a heat pump’s vents, filters or outdoor unit and cause the pump to freeze.

A failed defrosting mode is another culprit. Most heat pumps include an automatic defroster, operated by a sensor, which will kick in to clear light frost and ice from the unit’s coils. If the defrosting system fails for some reason, the heat pump will continue accumulating ice until the unit fails altogether.

Other reasons for a freezing heat pump include low refrigerant, dirty filter, damaged sensor or other internal components, and a failed blower motor.

What to do about a frozen heat pump

A frozen heat pump requires immediate attention. If you have a freezing pump, act fast:

  • Turn it off immediately. The pump will want to continue operating but doing so can cause serious damage. In addition, never attempt to repair an electrical device while power is still connected.
  • Check the easy stuff, like a clogged filter or a curtain of matted leaves plastered against the outdoor unit.
  • If you notice ice on the coils, you can often remove it carefully but if a hard-bristled brush doesn’t do the trick; try slowly pouring warm water over the coils to melt the ice. If the ice persists and you can’t wait for warmer weather, call in a pro.
  • Move the sensor to a more favorable location.