No, it is simply the defrost cycle that is causing this phenomenon. As the cold weather arrives and temperatures approach the freezing point or drop below 0 degrees Celsius, it is normal to see water vapour escaping from the heat pump and to see a thin layer of ice on the outside coil of your heat pump when it is in heating mode. This phenomenon is your heat pump’s defrosting cycle and is essential to its proper operation. The ice on the outdoor coil melts due to the defrost mode, causing water vapour to escape, which is similar to a light white mist.
The defrost cycle can be carried out every 30, 60 or 90 minutes or on request if necessary.