Does a heat pump in winter? Yes. Even in freezing conditions, there is still heat in the outside air, and an air-to-water heat pump is designed to utilise it. However, efficiency decreases as it gets colder. A well-chosen and properly set up heat pump will keep your home comfortable even in a cold winter. In this article, you can read what happens when it freezes and what you can do yourself.
- Even in freezing conditions, there is still heat in the outside air that a heat pump can utilise
- The colder it is, the lower the efficiency; the lower limit varies per model
- Vapour or ice on the outdoor unit is normal: the heat pump defrosts itself
- Keep the temperature as constant as possible; deep night-time setback actually costs energy
How a heat pump extracts heat from cold air
A refrigerant flows through the outdoor unit, which evaporates at very low temperatures. This allows it to absorb heat even from cold air. A compressor raises that heat to a higher temperature and transfers it to your heating water. The colder the outside air, the harder the compressor has to work and the lower the efficiency. The minimum outdoor temperature at which a heat pump operates is stated in the manufacturer's specifications.
Vapour and ice on the outdoor unit: defrosting is normal
At temperatures around and below freezing point, ice can form on the fins of the outdoor unit. The heat pump then defrosts itself automatically. During this phase, you may sometimes see a cloud of vapour near the outdoor unit and the heating temporarily stops providing heat. This is normal. Important points:
- The meltwater must be able to drain freely; proper placement with drainage prevents an ice sheet under the unit.
- Keep the air intake free of snow and leaves.
- If the unit is completely covered in ice and no longer defrosts, contact your installer.
Hybrid or all-electric in winter
With a hybrid heat pump the central heating boiler assists if it is very cold outside or if the heat pump cannot achieve the desired temperature efficiently. An all-electric heat pump is dimensioned to heat your home even on cold days, possibly with an electric auxiliary heating element for the coldest moments. You can read which one suits your home in hybrid or fully electric.
How to heat efficiently with a heat pump in winter
- Keep the temperature constant. A heat pump operates most efficiently at a steady, low water temperature. A deep night-time setback forces it to heat up intensely in the morning.
- Have the heating curve set correctly. This determines how warm the heating water becomes at a specific outdoor temperature. Read heat pump and water temperature.
- Do not close radiators and underfloor heating in rooms you use; allow the heat to distribute evenly.
- Have the installation maintained. See heat pump maintenance.
What does a heat pump cost and what subsidy is available?
For an air-to-water heat pump, including a hybrid, you can in 2026 Applying for ISDE subsidy if the appliance is on the RVO appliance list. You can read about the purchase and installation costs at heat pump costs and what does a heat pump cost. Do you want to know if your home is suitable? Request a free, no-obligation quote, then we will assess on-site.
Energie Install provides professional services from Amstelveen and Halsteren — with free advice and a clear quote upfront.
Frequently asked questions
Does a heat pump work when it's freezing?
Yes. An air-to-water heat pump extracts heat from the outside air even when it's freezing. The efficiency is lower then; the temperature range a model works in is stated in the specifications.
Why is smoke coming from my heat pump?
That's not smoke, but steam. The outdoor unit defrosts itself when there is ice on the fins; this releases water vapour. This is normal.
Should I turn down the heat pump at night?
Preferably not by much. A heat pump operates most efficiently at a constant temperature. A large night-time reduction actually costs extra energy in the morning.
Is a heat pump more expensive to use in winter?
In winter, you use more electricity because you heat more and the efficiency is lower. Over the entire heating season, a well-adjusted heat pump is economical.
Does a heat pump need maintenance before winter?
A periodic check is sensible. Check yourself that the outdoor unit is clear and that meltwater can drain away.
Curious about what this means for your home?
Request a no-obligation quote or start with the free sustainability check for your address.
