Like all heating systems, heat pumps need to work that little bit harder during the winter months to keep your home warm and comfortable. Because of how they work (i.e., pulling heat from the surrounding air, ground, or water), many homeowners ask us, how do heat pumps work in winter?
The good news is that heat pumps remain one of the most energy-efficient and eco-friendly heating systems out there, even in cold weather. Air source or ground source, Panasonic, NIBE, Stiebel Eltron, or Glen Dimplex. Regardless of brand or type, proper knowledge is key.
Understanding how your heat pump works and the necessary steps to keep it in tip-top shape will help you get the most from your system, keep bills under control, and reduce the likelihood of an unexpected breakdown at the worst possible time.
How Does a Heat Pump Work in Winter?
Heat pumps work by extracting warmth from the air, ground, or water, and transferring it indoors. And although it may sound strange, this is still entirely possible even in very low temperatures. Below is a quick breakdown of how the two most common types of heat pump (air source and ground source) work during winter.
Air Source Heat Pumps
Even cold air contains usable heat energy. An air source heat pump captures this heat and “upgrades” it to a higher temperature to heat the home and hot water.
- Air is drawn into the system, even when temperatures fall below zero.
- The refrigerant absorbs heat from the air (it can boil at very low temperatures, sometimes even as low as –20°C).
- The compressor increases the pressure of the refrigerant, raising the temperature significantly.
- The hot refrigerant then releases its heat into your home via radiators, underfloor heating, or a hot water cylinder.
- The refrigerant then cools, returns outside, and the cycle repeats.
Air source heat pumps work best in well-insulated homes and those with large radiators or underfloor heating, as these systems operate at lower temperatures. Weather-compensated controls and automatic defrost cycles also help maintain efficiency in winter. It’s also crucial to ensure you have the correct size and design air source heat pump for your home to ensure reliable, efficient performance all year round.
Ground Source Heat Pumps
Ground source heat pumps rely on the relatively stable temperatures underground to generate heat. This makes them particularly effective during winter.
- Heat is collected from the ground via a network of pipes buried in the garden.
- A mixture of water and antifreeze circulates through the pipes, absorbing heat from the ground.
- This heat is then “upgraded” as absorbed heat is passed to a refrigerant, and the compressor increases its temperature.
- Heat is delivered to the home, and the fluid returns underground to collect more heat, repeating the cycle.
Although ground source heat pumps are generally on the slightly more expensive side, they are ideal for properties with large gardens and offer excellent, consistent performance whatever the season.
Essential Tips for Maintaining Your Heat Pump Over Winter
Looking after your heat pump over winter ensures it runs as it should when you need it most, i.e., when it’s freezing outside, and you’ve got all the family round for Christmas! It also reduces general wear and tear, minimises the risk of costly breakdowns, and extends the lifespan of your system.
- Keep the outdoor unit clear of debris like leaves, snow, and ice, as this can obstruct airflow and reduce efficiency.
- Set a stable temperature and avoid constantly tweaking the thermostat, as this increases stress on the system and consumes more energy.
- Check and clean filters every few months to boost efficiency and improve indoor air flow; clogged filters restrict airflow.
- If it’s extra cold, watch for ice buildup. Many systems have automatic defrost cycles, but some may require manual intervention.
- Consider a smart thermostat to monitor and maintain consistent temperatures, set heating schedules, and make remote adjustments.
- Book an annual service with a qualified HVAC professional to check refrigerant levels, coils, and electrical components.
For further advice or to schedule a professional service, contact Heat Pump Tech on 01757 616636.
Note: Ground source heat pumps generally require less winter maintenance, but it’s still important to check pipes and connections, look out for any sudden drops in performance, and ensure your insulation is up to standard to get the most out of your system.
Frequently Asked Questions about Heat Pumps in Winter
1. Will my heat pump cost more to run during winter?
Heat pumps are still far more efficient than gas boilers, even in cold conditions. However, as with any system, the colder it is outside, the more energy is needed to maintain a level of comfort inside. This is normal and should be factored into your winter energy usage.
To keep heating costs under control:
- Run your heat pump steadily rather than switching it on and off, as heat pumps work most efficiently when maintaining a consistent temperature.
- Avoid large temperature setbacks because reheating a cold home uses more energy than maintaining warmth.
- Consider a flexible energy tariff, which allows for higher winter usage and balances it out during lower-use summer months.
- Make use of smart or weather-compensated controls to optimise performance and avoid unnecessary energy use.
2. Why is there steam coming from my heat pump?
In cold or humid weather, your heat pump may run a routine defrost cycle. During this, you may notice plumes of steam, but this is nothing to be worried about. Radiators may also feel cooler for a short time, but heating will return to normal once the defrost cycle ends (typically within 10 minutes).
3. Should I turn my heat pump off during very cold weather?
No. You should not turn your heat pump off when it’s really cold outside. Heat pumps work best when they’re left on at a steady temperature. If you turn it off, you’re forcing the system to work harder to reheat your home when you switch it back on. This reduces efficiency and increases running costs.
4. What are weather compensation controls?
Weather compensation controls adjust your heat pump’s output automatically based on the outdoor temperature. When it’s colder outside, the system increases heat delivery; when it’s milder, it reduces output. This helps maintain a consistent indoor temperature while using energy more efficiently.
5. What are other ways I can improve heat pump efficiency over winter?
You can boost your heat pump’s performance by maintaining a steady temperature, keeping the outdoor unit clear, scheduling regular servicing, using smart controls or zoning, and improving insulation and draught-proofing in your home.
