Winter is that time of the year when you need your heat pump most. Unfortunately, the cold weather conditions may cause your heat pump to ice up. You may find a bit of frost covering the entire coil but this is nothing to worry about because it is quite normal. However, if you find your entire unit encased in ice, there is obviously a problem and it needs to be addressed immediately. A heat pump completely iced up like that will cause higher energy consumption. It will also cause major and possibly irreversible damage to the unit.

While a heat pump is expected to ice up in cold weather, it is designed to defrost regularly in order to allow it to run smoothly and efficiently. If it doesn’t do this, it indicates a problem. When a unit goes into defrost, the outdoor evaporator changes its function and then acts as the condenser. The outdoor fan shuts off and in this manner, the refrigerant that circulates within the outdoor coil warms up and will then melt the ice.

Heat pumps are designed to automatically go into defrost mode. In older pumps, a thermostat triggers a mechanical timer that sets off the defrost mode if the temperature remains at a specified cold temperature for a period of time. In more recent models, digital control modules  are triggered by sensors.

There are many reasons that cause a heat pump to ice up. The following are some of the problems that can be easily remedied by owners without the need for a repair call.

  1. The outdoor coil is blocked – periodically check your unit to make sure that ice, leaves and other debris do not block the coil. If the top is covered with ice, you must remove the ice but make sure that the unit is turned off before doing so.
  2. The unit has settled into the ground – if this happens, it means that the melted ice will have nowhere to go to and will accumulate around the unit, thus causing damage. To avoid this problem, place the unit on blocks or have somebody create a special set of feet for the heat pump so that it is elevated.
  3. Water dripping on the heat pump – sometimes a heat pump is situated directly under a gutter which may in time acquire leaks. Dripping water will obviously cause damage to the heat pump so the leak must be repaired. If this cannot be done immediately, a makeshift “roof” or protective cover must be put in place in order to protect the heat pump.

If after going through these steps, your unit ices up again, it is best to call for a repair team to handle your problem.