How much does it cost to run a heat pump in winter? For a typical home needing about 8,550 kilowatt hours of heat a year, the answer at October to December 2026 price cap rates is roughly £640 to £800 a year for the heat itself, depending on how efficiently the system runs. A well set up system at a seasonal performance factor of 3.5 lands near the bottom of that range, while a system running at the field trial median of 2.8 lands near the top. On the coldest days, when efficiency drops further, each unit of heat costs more than the same heat from a new gas boiler on a standard tariff. Over the whole winter, though, the honest answer is that a heat pump on a standard tariff costs roughly the same as a new gas boiler to run, and it pulls ahead once you switch to a cheaper time of use tariff or disconnect the gas supply altogether.

The short answer: how much does it cost to run a heat pump in winter

There is no single winter bill for a heat pump, because the cost depends on three things: how much heat your home needs, how efficiently your heat pump delivers it, and what you pay for electricity. But the maths behind the answer is simple, and you can run it for your own home in under a minute. Take the heat your home needs in kilowatt hours, divide it by your heat pump seasonal performance factor, and multiply the result by your electricity price. That gives the cost of the heat, before standing charges.

Using the October to December 2026 price cap averages for Great Britain, electricity costs 26.32p per kilowatt hour and gas costs 7.97p per kilowatt hour for Direct Debit customers on standard variable tariffs. Those are national averages published by Ofgem and summarised by the Energy Saving Trust, and your own rates will vary by region and payment method. The cap is reviewed every three months, with the January to March 2027 rates due to be confirmed on 25 November 2026, so treat every figure here as a snapshot of the current cap, not a permanent price.

So, how much does it cost to run a heat pump in winter? For the example home below, the heating and hot water electricity costs about £54 to £67 a month averaged across the year, but winter months cost considerably more than summer months because that is when almost all the heat is needed. A cold month is where the bill bites, and a cold snap is where the cost per unit of heat peaks.

How to work out your own heat pump running cost

The formula is: electricity used equals heat needed divided by seasonal performance factor. Cost equals electricity used multiplied by your electricity unit price.

Seasonal performance factor, often shortened to SPF, is the average efficiency of the heat pump across a whole year. An SPF of 2.8 means the system delivers 2.8 units of heat for every unit of electricity it uses. It is not the same as the headline SCOP figure on a product datasheet, which is a laboratory seasonal rating. Real homes vary, which is why field trial data matters more than brochure numbers.

The best real world anchor we have is the government funded Electrification of Heat trial, run by the Department for Energy Security and Net Zero and Energy Systems Catapult. It monitored 742 heat pump installations in real homes, and the median air source heat pump achieved a seasonal performance factor of 2.80 across a year. That is the number to use for a realistic middle estimate, not the optimistic datasheet figure and not the worst case either.

Your heat demand is the other input. If you have a recent gas bill, your annual gas use in kilowatt hours divided by your boiler efficiency gives a rough heat figure. A home using 9,500 kilowatt hours of gas a year with a 90 percent efficient boiler needs about 8,550 kilowatt hours of heat. Your installer heat loss calculation or your Energy Performance Certificate gives a better figure, and if you are buying a heat pump, ask the installer for the predicted annual electricity use in writing before you sign.

Worked example: a typical home at current cap rates

Take a home needing 8,550 kilowatt hours of heat a year for space heating and hot water. At 26.32p per kilowatt hour of electricity, the annual cost of that heat is:

• At an SPF of 2.80, the field trial median: 8,550 divided by 2.80 equals 3,054 kilowatt hours of electricity, costing about £804 a year.
• At an SPF of 3.50, a well designed system with low flow temperatures: 8,550 divided by 3.50 equals 2,443 kilowatt hours of electricity, costing about £643 a year.
• At an SPF of 2.44, the trial median on the coldest days: each kilowatt hour of heat costs 26.32p divided by 2.44, which is about 10.8p.

Compare that with gas for the same 8,550 kilowatt hours of heat. A 90 percent efficient boiler burns 9,500 kilowatt hours of gas, which at 7.97p costs about £757 a year for fuel alone. So at the trial median efficiency, the heat pump costs about £47 a year more than a new gas boiler for fuel. At an SPF of 3.5, it costs about £114 a year less. That is why the Energy Saving Trust says that on standard electricity tariffs, where electricity costs nearly four times as much as gas per unit, heat pumps can cost slightly more to run than new gas or oil boilers, while switching to a heat pump time of use tariff can make a heat pump cheaper to run than a gas boiler.

Standing charges change the picture in one specific case. A home with a heat pump still pays the electricity standing charge, currently averaging 54.83p a day, but if you disconnect the gas supply entirely you stop paying the gas standing charge, currently averaging 29.68p a day, which is about £108 a year. That saving alone turns the median efficiency example above from slightly more expensive than gas into slightly cheaper. It only applies if you genuinely no longer need gas, for cooking as well as heating, so check before you disconnect.

What a cold month and a cold snap actually cost

Annual averages hide the winter experience, so here is a cold month worked as an example, not a statistic. Suppose a home needs 1,500 kilowatt hours of heat in a cold month. At the annual median efficiency of 2.80, that needs 536 kilowatt hours of electricity, costing about £141. At the coldest day efficiency of 2.44, the same heat needs 615 kilowatt hours, costing about £162. The difference, about £21 in one month, is the cold weather penalty, and it is normal, not a fault.

Why does efficiency fall when it is cold? A heat pump extracts heat from outdoor air, and colder air holds less usable heat, so the compressor works harder for each unit delivered. The Electrification of Heat trial found exactly this: the median air source system efficiency was 2.44 on the coldest days, against 2.80 across the year, even though performance held up far better than many sceptics expected, with only a relatively small reduction on days down to minus 6 degrees. Frost also forces the system into occasional defrost cycles, which use electricity without delivering heat to the house, and hot water demand stays constant while space heating demand peaks, which drags the average down further.

On the coldest days, heat from a heat pump on a standard tariff costs more per unit than heat from gas. At 10.8p per kilowatt hour of heat against about 8.9p for gas from a 90 percent efficient boiler, the gap is roughly 2p per unit. Over a single cold snap that might add a few pounds to a weekly bill. Over a whole winter it is partly offset by milder days, when efficiency climbs back above the annual median. This is also why a single cold week is a bad basis for judging a system: judge it over a season, and compare like with like, including standing charges and tariffs.

What pushes your winter bill up or down

Flow temperature is the biggest lever you control. A heat pump running radiators at 35 degrees is far more efficient than one forced to 55 degrees, because efficiency falls as the gap between outdoor temperature and flow temperature grows. Oversized radiators or underfloor heating let the system run cooler, which is why installers recommend radiator upgrades in some homes, and why the Energy Saving Trust lists appropriately sized radiators as a key factor in running costs.

Insulation is the second lever. A draughty home needs more heat in the first place, so every efficiency problem is multiplied. Loft insulation, draught proofing and, where suitable, wall insulation cut the heat demand itself, which cuts the bill whatever the tariff. Our thermostat guide explains the room by room temperatures that keep a home comfortable without overheating empty rooms, and that matters because a heat pump heating an empty house to 23 degrees all day will cost more than one holding steady at a sensible setpoint.

Controls and habits are the third lever. Heat pumps suit steady, low temperature running better than short, hot blasts, because each restart and each high temperature demand costs efficiency. That is the subject of our guide to whether it is cheaper to leave a heat pump running all day, and the short version is that setback temperatures, not full switch offs, usually work best. Weather compensation, which automatically lowers the flow temperature on milder days, is worth asking your installer about if your system does not already use it.

Finally, the tariff is the lever with the fastest payback. A standard variable tariff charges the same 26.32p all day, but a heat pump time of use tariff charges far less overnight, when the system can heat the home and the hot water cylinder cheaply. The Energy Saving Trust says its latest research shows that switching to such a tariff can reduce running costs significantly, enough to make a heat pump cheaper to run than a gas boiler. If you already have a heat pump and have never checked your tariff, that single check is the highest value action in this article.

Heat pump versus gas, oil and direct electric heating

Against a new gas boiler on a standard tariff, the honest verdict is roughly a tie, with the winner decided by your system efficiency and your tariff. Against an old, inefficient gas boiler, a heat pump usually wins, because the boiler wastes far more fuel turning gas into heat. Against oil, the Energy Saving Trust notes that heat pumps can cost slightly more than new oil boilers on standard tariffs, but oil prices swing with world markets and oil homes often qualify for the higher £9,000 Boiler Upgrade Scheme grant until 31 March 2027, which changes the upfront maths even when running costs are close. Against direct electric heating, such as storage heaters or panel heaters, a heat pump wins clearly, because direct electric heating delivers one unit of heat per unit of electricity, while a heat pump at the trial median delivers 2.8.

Upfront cost still matters to the overall decision, even though this article is about running costs. The Energy Saving Trust puts typical air source heat pump installation at around £12,000, with grants of up to £7,500 available in England, Scotland and Wales, which brings a typical install down to around £4,500 after the grant. Running cost savings alone rarely repay that difference quickly against a new gas boiler, so buy a heat pump for the combination of running costs, carbon savings and future proofing, not on a promise that it pays for itself in a year or two.

How to check whether your bill is reasonable

Start with your meter, not with averages. Note your electricity use over a winter month, subtract your normal household electricity use for lights, cooking and appliances, and the remainder is roughly your heating and hot water use. Divide your estimated heat demand by that electricity figure and you have your own seasonal performance factor so far. If it is well below 2.5 across a mild month, something is worth investigating: high flow temperatures, undersized radiators, a system running without weather compensation, or a fault such as low refrigerant or a stuck diverter valve.

Our guide to why a heat pump bill might be high walks through nine causes and fixes in detail, from thermostat settings to installer errors. Before calling an engineer, check the simple things: radiators that are cold at the bottom, a flow temperature set far above what the house needs, and a tariff that charges peak rates all day. If the system is new, give it a full heating season before judging it, and ask the installer to review the settings after the first winter, when real data replaces estimates.

The bottom line on heat pump running costs in winter

How much does it cost to run a heat pump in winter? At October to December 2026 cap rates, a typical home needing 8,550 kilowatt hours of heat pays roughly £640 to £800 a year for that heat, with winter months carrying most of the cost and cold snaps costing about 10.8p per unit of heat against 8.9p for gas. On a standard tariff that is roughly level with a new gas boiler, slightly more at median efficiency and slightly less at good efficiency, and disconnecting gas saves about £108 a year in standing charges on top. Switch to a heat pump time of use tariff and the balance tips clearly in the heat pump favour. The cheapest heat pump to run is not the one with the best brochure rating, it is the well insulated home with low flow temperatures, sensible controls and the right tariff, and every one of those is within your control.

Frequently asked questions

How much does it cost to run a heat pump in winter per month?

It varies by month, because winter months need far more heat than summer months. For a home needing 8,550 kilowatt hours of heat a year, the annual cost at October to December 2026 cap rates is roughly £640 to £800, averaging about £54 to £67 a month across the year, but a cold month needing 1,500 kilowatt hours of heat costs about £141 to £162 depending on efficiency. Budget by the season, not by a single month.

Is a heat pump cheaper to run than a gas boiler in winter?

On a standard tariff, roughly the same. At the field trial median efficiency of 2.80, a heat pump costs slightly more than a new gas boiler for the same heat, while at an efficiency of 3.50 it costs less. On a heat pump time of use tariff, or after disconnecting gas and saving about £108 a year in standing charges, a heat pump usually comes out cheaper.

Why is my heat pump so expensive to run in cold weather?

Efficiency falls as outdoor temperatures fall, because the system works harder to extract heat from colder air, and defrost cycles use electricity without heating the house. The Electrification of Heat trial found median efficiency fell from 2.80 across the year to 2.44 on the coldest days. High flow temperatures, poor insulation and a standard tariff make the cold weather penalty worse.

Does a heat pump use a lot of electricity in winter?

It uses more electricity in winter than in summer, because that is when heat demand peaks, but it still uses far less electricity than direct electric heating for the same heat. A home needing 8,550 kilowatt hours of heat a year uses about 3,054 kilowatt hours of electricity at an efficiency of 2.80, against 8,550 kilowatt hours for direct electric heaters.

What is a good seasonal performance factor for a heat pump?

The Electrification of Heat trial median for air source heat pumps was 2.80, so anything around 2.8 is typical for a real home, while 3.5 or above is good and usually reflects low flow temperatures, well sized radiators and good insulation. Below 2.5 across a heating season is worth investigating with your installer.

Related reading

• Is It Cheaper to Leave a Heat Pump Running All Day?
• Why Is My Bill So High With a Heat Pump? 9 Causes and Fixes
• What Is the Most Economical Way to Run an Air Source Heat Pump?

Sources

• Energy Saving Trust: Air Source Heat Pumps, costs, savings and benefits
• Energy Saving Trust: Ofgem energy price cap explained, October to December 2026 rates
• Energy Systems Catapult: Electrification of Heat trial, median air source heat pump seasonal performance factor 2.80, 2.44 on the coldest days