When the temperature drops, Heat Pumps perform a defrost cycle to remove ice build-up on the outdoor heat exchanger. Ice build-up occurs during the heat process as the outdoor unit takes the moisture and heat from the air.
The defrost cycle is a necessary part of the Heat Pump’s operation, as the airflow can be restricted if the heat exchanger is covered in ice, which will subsequently affect its efficiency. Ice also acts as a thermal insulation barrier on the heat exchanger preventing heat absorption. By defrosting the heat exchanger the unit’s efficiency increases.
In defrost mode the Heat Pump will stop heating for short periods of time and it’s important not to turn your system off when it’s going through this cycle.
