Yes, an air-to-water heat pump also heats in frost. Even very cold air still contains heat that it can extract. However, as the outdoor temperature falls, its output and efficiency fall too – and the design has to allow for this. The manufacturer states the range of operating temperatures for each model.
What happens at low temperatures
- a heat pump needs more electricity for the same amount of heat,
- the house also needs more heat,
- at the lowest temperatures a supplementary source may help – A heat pump and a backup heat source: fireplace, boiler or electricity.
It is therefore important to design the output according to the heat loss for the coldest days in your area – What heat pump output do I need?.
Defrosting is normal
At temperatures around zero and with higher humidity, ice forms on the heat exchanger of the outdoor unit. The heat pump defrosts it automatically – it interrupts heating for a short time and steam may rise from the unit. This is a normal part of operation, not a fault.
What to consider when positioning the unit
- defrost water must have somewhere to drain and must not freeze on a path,
- the unit must not be buried in snow or placed where snow falls from the roof,
- free space for airflow must remain around the unit.
Read more in the article Heat pump noise and the location of the outdoor unit.
Myth: a heat pump is only for mild winters
Air-to-water heat pumps are commonly used in countries with colder winters than those in the Bratislava Region. The right design is what matters, not the technology itself.
What to do if it cannot keep up in frost
- Check that the outdoor unit is not clogged with snow or ice.
- Look at the error messages.
- Check the heating curve setting – Weather-compensated heat pump control: how to set the heating curve.
- If the problem persists, book a service – Heat pump servicing: what it includes and how often.
We design and install Daikin heat pumps in Bratislava and the surrounding area. Contact us · Daikin heat pumps
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