Do Heat Pumps Cost More to Run in Winter Than Summer?

Yes. In almost every UK home, a heat pump costs more to run in winter than it does in summer. That's not a fault, and it isn't a sign anything has gone wrong. It simply reflects the basic reality that your home needs far more heat when the weather turns cold.

During summer, most heat pumps only heat the domestic hot water cylinder for a short period each day. Once it reaches temperature, the system switches back to standby and sits there using very little electricity. Winter is a completely different story. The system is heating your home for many hours every day while still producing hot water on top of that, so electricity consumption rises naturally as a result.

Why do heat pumps cost more to run in winter?

The biggest reason comes down to one simple fact: your house loses far more heat in winter than it does in summer. When it's 20°C outside, your home loses relatively little heat through the walls, roof, windows, and floor. When it's close to freezing, that heat loss increases sharply. Your heat pump has to replace every bit of that lost heat to keep the house comfortable, and the colder it gets outside, the harder the system has to work to keep up. That's exactly what it's built to do.

Heat pumps are most efficient in milder weather

Air source heat pumps perform best when outdoor temperatures are mild. The warmer the outside air, the easier it is for the system to extract heat from it and transfer that heat into your home. As outdoor temperatures drop, the compressor has to work harder to reach the same flow temperature. The heat pump still remains highly efficient compared with most traditional heating systems, but it will naturally use more electricity than it would on a mild spring or summer day. This is completely normal and part of how every air source heat pump is designed to operate. Understanding what flow temperature your system should actually be running at is a useful next step here, and we cover that in detail in Heat Pump Flow Temperature: What Should It Be?

Winter running costs are higher for more than one reason

It isn't just the colder air itself driving up electricity use. Over winter, your heat pump is also likely to run for longer each day, produce more heating on top of hot water, operate at higher flow temperatures if your heating system requires it, and carry out occasional defrost cycles when outdoor conditions demand them. Each of these adds to electricity usage individually, but all of them are part of completely normal winter operation, not signs of a problem.

What about summer?

For many households, summer is when the heat pump is at its absolute cheapest to run. With the heating switched off, the system is often only heating the hot water cylinder once or twice a day before dropping back to standby. Modern heat pumps use very little electricity while waiting for the next demand, which is why summer running costs often come as a pleasant surprise. If your system also provides cooling, electricity consumption will rise a little while cooling is active, though this is still generally far lower than heating an entire home through the winter months. If you're curious how that trade-off actually works, our article on Can a Heat Pump Cool Every Room in the House? covers what's needed to run cooling well.

Does a higher winter electricity bill mean something is wrong?

No, not on its own. A higher bill during winter is exactly what you should expect. As outdoor temperatures fall, your home loses more heat, so the heat pump runs for longer to keep things comfortable, and higher winter consumption is simply part of normal operation.

That said, your bills should still be proportionate to your property and the weather you're actually experiencing. If running costs seem unusually high, your home struggles to stay warm despite the system working hard, or your electricity bills have jumped noticeably compared with previous winters, it's worth investigating properly rather than assuming it's just "how heat pumps are." Common causes worth ruling out include incorrect weather compensation settings, poor commissioning at installation, a heating circuit that hasn't been balanced correctly, flow temperatures set higher than they need to be, an immersion heater kicking in unnecessarily, or heating controls that were never configured properly in the first place. Several of these are covered in more depth in our guides on heat pump system balancing and why a heat pump might keep turning off, both of which walk through symptoms that often trace back to the same underlying settings issues. Most of these problems are relatively straightforward to resolve once identified, and fixing them can noticeably improve both comfort and running costs.

The bottom line

Yes, heat pumps cost more to run in winter than in summer, and that's completely normal. Your home loses far more heat in colder weather, so the system has to work harder and run for longer to replace it. Higher winter electricity consumption doesn't automatically mean there's a fault. If your heat pump is keeping your home warm, producing hot water efficiently, and your bills are broadly in line with what you'd expect for your property, it's very likely doing exactly what it was designed to do. A correctly designed and commissioned system should provide steady, comfortable heating while running as efficiently as possible throughout the winter months.

Need help with your heat pump?

If your heat pump isn't performing as expected, our Fix My Heat Pump service provides independent remote support to identify faults, incorrect settings, commissioning problems, and design issues before you spend money on unnecessary repairs. If you're planning a new installation, replacing an existing system, or comparing quotations, our Pre-Installation Heat Pump Review provides an independent assessment to help make sure the system is designed correctly from the start.