One of the most common questions about heat pumps is whether they work properly during cold British winters. The good news? Heat pump COP in cold weather remains strong even when temperatures drop, and modern systems continue heating your home efficiently throughout the UK’s winter months. This article shares real performance data from actual UK installations, showing you exactly what to expect when temperatures fall. The numbers are straightforward, the technology works, and thousands of British homeowners are staying warm and comfortable with heat pumps right now.
What Is COP and Why Does It Drop in Cold Weather?
COP stands for Coefficient of Performance, which sounds technical but is actually quite simple. It tells you how efficient your heat pump is—how much heat you get for the electricity you use.
Here’s how it works: a COP of 3 means your heat pump produces 3 units of heat for every 1 unit of electricity it consumes. That’s three times more efficient than an electric heater, and significantly better than even the best gas boilers.
When the weather gets colder, heat pump COP in cold weather does decrease somewhat. This happens because the system has to work a bit harder to extract heat from colder air. Think of it like this: pulling heat from 10°C air is easier than pulling it from -5°C air, so the system uses slightly more electricity to produce the same amount of warmth.
But here’s the important part: this decrease is completely normal and expected. Heat pumps are designed to work in cold weather (click here to learn how), and even with a lower COP, they still dramatically outperform traditional heating systems.
Here’s what you can realistically expect from a modern heat pump throughout winter:
| Outside Temperature | What You Can Expect (COP) | What This Means |
|---|---|---|
| Mild day (+10°C) | 4.0–5.0 | Excellent efficiency—produces 4-5x the heat vs electricity used |
| Cool day (+7°C) | 3.5–4.5 | Very good efficiency—typical autumn/spring performance |
| Cold day (0°C) | 2.6–3.2 | Good efficiency—still 2.5-3x better than direct electric heating |
| Freezing (-5°C) | 2.0–2.7 | Fair efficiency—still works well, slightly higher running costs |
Even at -5°C, a heat pump achieving COP 2.5 is still producing 2.5 times more heat than the electricity it uses. That’s far better than any traditional heating method and keeps your home comfortably warm.
UK Winter Temperatures: What Heat Pumps Really Face
Understanding typical UK winter weather helps put heat pump winter performance UK into perspective. Our winters are actually quite mild compared to many countries where heat pumps work perfectly well.
- England typically sees winter temperatures between 0°C and 8°C. Most winter days sit comfortably in the 3-7°C range, which is ideal for heat pump operation. London and the South East rarely experience prolonged freezing conditions.
- Scotland is colder, with winter temperatures usually ranging from -2°C to 6°C. Even in Scotland, though, extreme cold is relatively rare. Cities like Edinburgh and Glasgow average around 3°C in January.
- Wales experiences winters similar to England, typically between 1°C and 7°C. Coastal areas benefit from maritime influence and stay particularly mild throughout winter.
Here’s the key point: Genuinely cold weather (below -5°C) happens only occasionally in most UK regions—perhaps a few nights each winter rather than for weeks at a time. Research shows that during the heating season, UK temperatures stay above 0°C roughly 85% of the time.
This means your heat pump spends the vast majority of winter operating in conditions where it performs excellently. The occasional cold snap might reduce efficiency temporarily, but it doesn’t stop your home from staying warm.
Real UK Examples of Heat Pump COP in Cold Weather
Let’s look at real heat pump performance examples from actual UK homes during winter. These aren’t manufacturer claims or laboratory tests—they’re measurements from working systems in British properties.
Example 1: 0°C Night in Manchester
A typical winter night with outdoor temperature at 0°C. The home had an 8kW heat pump heating a 1980s semi-detached house with standard insulation.
What happened:
- Outside temperature: 0°C
- Inside temperature maintained: 20.5°C
- Performance measured: COP 2.9
- Result: Home stayed warm and comfortable all night
At COP 2.9, this homeowner got nearly three times more heat than the electricity consumed. The system ran steadily throughout the night, maintaining consistent warmth without any issues.
Example 2: -3°C Morning in Scotland
A January morning near Inverness when temperatures dropped to -3°C. The property had a 12kW system heating a modern, well-insulated home.
What happened:
- Outside temperature: -3°C
- Inside temperature maintained: 21°C
- Performance measured: COP 2.4
- Result: System ran longer but kept the house perfectly warm
Even at this colder temperature, UK heat pump efficiency cold weather remained good. The heat pump ran for longer periods during the cold spell, but the house never felt cold and heating costs stayed reasonable.
Example 3: Coastal Wales During a Cold Snap
A brief cold period in Aberystwyth with temperatures at -1°C. The property had a 6kW system with underfloor heating and good insulation.
What happened:
- Outside temperature: -1°C
- Inside temperature maintained: 20°C
- Performance measured: COP 2.7
- Result: Steady, comfortable heating throughout
This system benefited from underfloor heating, which works brilliantly with heat pumps. Even during the cold snap, performance remained strong and the home stayed cosy.
The pattern is clear: Across different UK regions and weather conditions, air source heat pump COP at low temperatures consistently delivers between 2.4 and 3.0 during typical winter weather. That’s more than enough to keep your home warm whilst still operating far more efficiently than traditional heating systems.
Why UK Heat Pumps Maintain Good COP Even When It’s Freezing
Several factors explain why heat pump winter performance UK remains strong even when it’s cold outside.
- Modern technology has improved dramatically. Today’s heat pumps are vastly better than models from even five years ago. They include smarter controls, better components, and advanced features that help them work efficiently in cold weather.
- The UK climate is actually ideal for heat pumps. Compared to continental Europe or North America, British winters are mild. Our maritime climate means we rarely face the extreme cold (-20°C or colder) that genuinely challenges heat pump performance. Most winter operation happens in the 0-7°C range where modern systems excel. Here is a simple guide on how heat pumps actually work.
- Heat pumps run continuously at lower power rather than blasting heat then shutting off like traditional boilers. This steady operation proves more efficient and comfortable, particularly during cold weather. Your home maintains consistent warmth rather than cycling between hot and cold.
- Smart controls adjust automatically to weather conditions. When it’s mild, your heat pump runs at lower intensity, saving energy. When it’s cold, it increases output to maintain comfort. You don’t need to constantly adjust settings—the system handles it for you.
- Lower water temperatures are key. Heat pumps work best when heating water to 40-45°C (for radiators) or 30-35°C (for underfloor heating). This is much cooler than traditional boilers but still provides plenty of warmth. Operating at these moderate temperatures keeps efficiency high even when it’s freezing outside.
How to Maximise Heat Pump COP in UK Winter
You don’t need to be technical to help your heat pump work efficiently during cold weather. These straightforward tips make a real difference.
- Keep your flow temperature around 40-45°C if you have radiators, or 30-35°C for underfloor heating. Don’t be tempted to crank it up higher “just in case”—your home will stay warm at these settings whilst your system runs more efficiently. To learn more about it.
- Let the system run steadily rather than turning it on and off. Heat pumps work best maintaining consistent warmth throughout the day, not heating a cold house quickly. Set your thermostat to a comfortable temperature and leave it there.
- Make sure radiators aren’t blocked by furniture or curtains. Good airflow helps them work effectively at lower temperatures, meaning your heat pump doesn’t need to work as hard.
- Improve your insulation if you can. Loft insulation, draught-proofing around windows and doors, and cavity wall insulation all reduce heat loss. Less heat escaping means your heat pump runs more efficiently and your home stays warmer.
- Avoid using boost mode unless really necessary. Boost forces the system to run at very high temperatures, dramatically reducing efficiency. Normal operation keeps you warm more economically.
- Keep indoor temperatures steady rather than letting your home get cold then reheating it. Heat pumps achieve their best performance maintaining constant comfort rather than compensating for big temperature swings.
These simple approaches help maximise heat pump winter performance UK without requiring any technical knowledge or complicated adjustments.
Want to get even more out of your heat pump this winter?
Check out our guide to the best heat-pump settings for winter in the UK and start saving right away.
What COP Means for Running Costs in Winter
Understanding how heat pump COP in cold weather affects your actual costs helps set realistic expectations about heat pump running costs winter UK.
Using typical 2025 UK electricity prices (around 29 pence per unit):
When your heat pump operates at a COP of 3.0 (typical for much of winter):
- Every pound spent on electricity produces £3 worth of heat
- Cost per unit of heat: roughly 10 pence
- This is competitive with gas heating
When the COP drops to 2.5 (during colder periods):
- Every pound spent produces £2.50 worth of heat
- Cost per unit of heat: roughly 12 pence
- Still cost-effective and far better than electric heaters
If the COP falls to 2.0 (rare, only during very cold snaps):
- Every pound spent produces £2 worth of heat
- Cost per unit of heat: roughly 15 pence
- Higher than gas but remember this only happens occasionally
For comparison, gas boilers:
- Gas costs about 7 pence per unit
- Boilers are roughly 90% efficient
- Effective cost: around 8 pence per unit of heat
Over a full winter, your heat pump spends most time operating at COP 2.8-3.5, meaning average costs stay competitive with gas heating. When you factor in that heat pumps eliminate annual boiler servicing costs and gas safety checks, plus the £7,500 government grant reducing installation costs, the overall economics work well for most UK households.
If you’re replacing oil, LPG, or electric heating, heat pumps deliver substantial savings regardless of winter COP. These fuels are significantly more expensive than electricity on a heat-per-pound basis.
Summary: Heat Pump COP in Cold Weather UK
The evidence is clear: heat pump COP in cold weather remains strong throughout British winters. Real data from homes across England, Scotland, and Wales consistently shows COP values between 2.4 and 3.0 during typical winter conditions, with many systems performing even better.
Heat pumps continue working efficiently well below freezing. They deliver reliable warmth even during the coldest UK weather, and thousands of British homeowners are already experiencing this firsthand. The technology works, the performance is proven, and concerns about cold-weather operation are largely unfounded for UK conditions.
Your heat pump will run slightly longer during cold spells and efficiency decreases somewhat, but your home stays warm and comfortable. With proper settings and reasonable insulation, most UK properties achieve excellent results throughout winter.
The combination of our relatively mild climate, advancing heat pump technology, and generous government support through the £7,500 Boiler Upgrade Scheme makes this an increasingly sensible choice for British homes. Heat pumps aren’t just a future technology—they’re a practical, proven solution working successfully in UK homes right now.
Curious about how to maximise your heat pump’s efficiency?
Read our 2025 UK guide on the ideal flow temperature for air-source heat pumps and optimise your system with confidence.
Sources
- GetMyHeatPump. (2025). “How Heat Pumps Work: Efficiency & Performance Guide UK 2025.” https://www.getmyheatpump.co.uk/guides/how-heat-pumps-work-efficiency-performance-uk
- Aventus Eco. (2025). “Air Source Heat Pump Performance in Scotland: 2025 Guide.” https://aventuseco.com/how-efficient-are-air-source-heat-pumps-in-scottish-winters-2025/
- PICKHVAC. (2025). “Heat Pump Efficiency by Temperature: COP Curves, Ratings, and Smart Cold-Weather Strategies.” https://www.pickhvac.com/heat-pump-efficiency-temperature-cop-curves-smart-cold/
- PICKHVAC. (2025). “Heat Pump Efficiency vs Temperature: Performance in Cold and Warm Weather.” https://www.pickhvac.com/heat-pump-efficiency-temperature-performance-cold-warm/
- AFM Plumbing Heating. “Understanding Heat Pump COP Ratings: A Practical Guide.” https://afmplumbingheating.com/understanding-heat-pump-cop-practical/
- AFM Plumbing Heating. “Lowest Temperature for Heat Pumps: Cold Climate Performance and Backup Heating.” https://afmplumbingheating.com/lowest-temperature-heat-pumps-cold-climate-performance/
- The Furnace Outlet. (2025). “Cold-Climate Performance: How Modern 3-Ton Heat Pumps Handle Freezing Weather.” https://thefurnaceoutlet.com/blogs/hvac-tips/cold-climate-performance-how-modern-3-ton-heat-pumps-handle-freezing-weather
- Heat Pump House. (2024). “Heat Pump COP (Coefficient of Performance).” https://heatpumphouse.com/guides/heat-pump-cop/
- GOODHEAT. (2025). “Air to Water Heat Pump COP Ratings Explained.” https://www.goodheatglobal.com/Air-to-Water-Heat-Pump-COP-Ratings-Explained-id47881106.html
- UK Collaborative Centre For Housing Evidence. (2025). “The great heat pump mystery: where’s the COP?” https://housingevidence.ac.uk/the-great-heat-pump-mystery-wheres-the-cop/