Heat pump running costs depend on three main things: how much heat your home needs, how efficiently the heat pump produces that heat, and what you pay for electricity. A well-designed heat pump can be cheap to run, especially with the right tariff, but a poorly sized or badly installed system can cost more than expected.
The important number is the heat pump’s seasonal efficiency, often shown as SCOP. This tells you how many units of heat the system produces for each unit of electricity it uses across the year. Once you know that, you can compare the cost of heat from a heat pump with gas, oil, LPG or direct electric heating more fairly.
The two numbers that matter: SCOP and unit rate
The Coefficient of Performance (COP) tells you how much heat a pump produces per unit of electricity. A COP of 3.0 means three units of heat for every one unit of electricity. The Seasonal Coefficient of Performance (SCOP) averages that across a full UK heating season, so it’s the figure that actually predicts your bills.
Under the Ofgem Q2 2026 price cap, the average electricity unit rate is 24.67p/kWh and gas is 5.74p/kWh. Electricity is roughly four times the price of gas per unit, which sounds disastrous for heat pumps until you factor in efficiency.
At SCOP 3.0, a heat pump delivers heat for about 8.2p per kWh of useful heat (24.67p ÷ 3.0). A 90% efficient gas boiler delivers heat for about 6.4p per kWh (5.74p ÷ 0.9). Gas still wins narrowly. At SCOP 4.0, the heat pump comes in at 6.2p per kWh, which flips the comparison. A heat pump tariff swings it harder still, because the unit rate during off-peak windows drops to around half the cap.
Typical annual running costs by property
The figures below are illustrative, assume SCOP around 3.2, and use the Q2 2026 electricity price cap. Real homes vary. Solid-wall detached properties without insulation can run materially higher.
| Property type | Standard tariff | Heat pump tariff |
|---|---|---|
| 1-bed flat | £450 to £650 | £250 to £400 |
| 2-bed terrace | £700 to £900 | £350 to £550 |
| 3-bed semi | £900 to £1,200 | £450 to £700 |
| 4-bed detached | £1,300 to £1,800 | £650 to £1,000 |
These are figures for a competent install in a home with sensible insulation. A poorly commissioned heat pump running at SCOP 2.2 because the flow temperature is stuck at 55°C will cost considerably more than the upper end of these ranges.
Heat pump vs gas boiler running costs
For a 3-bed semi with annual heat demand of around 12,000 kWh, a SCOP 3.2 heat pump on a standard tariff costs roughly £925 a year for heating and hot water. A modern gas boiler covering the same demand at 90% efficiency costs about £850 a year on Q2 2026 gas prices, before the gas standing charge.
On those numbers it’s a wash, give or take £50 either way. The picture changes on a heat pump tariff. The same heat pump on Octopus Cosy, with most of the heating shifted into the off-peak windows, lands closer to £550 a year. That’s a real saving of £300 to £500 against gas.
Some installer marketing quotes savings north of £500. Those numbers usually assume both a heat pump tariff and a SCOP above 3.5. Plenty of installs hit that. Plenty don’t.
Replacing oil or LPG is a different story. Heat pumps almost always win, often by £400 to £700 a year against oil at 2026 prices, and more against LPG.
Cost of delivered heat by fuel
This is the cleanest way to see why SCOP matters so much.
| Fuel | Cost per kWh of delivered heat |
|---|---|
| Gas (90% boiler) | ~6.4p |
| Oil (85% boiler, late 2025 prices) | ~7.5p |
| LPG (90% boiler) | ~10p+ |
| Heat pump, SCOP 2.8, standard tariff | ~8.8p |
| Heat pump, SCOP 3.2, standard tariff | ~7.7p |
| Heat pump, SCOP 4.0, standard tariff | ~6.2p |
| Heat pump, SCOP 3.2, Cosy off-peak | ~4.5p |
The bottom row is the prize. It’s also conditional on actually shifting heating use into the cheap windows.
Why tariff choice changes everything
After SCOP, tariff is the single biggest lever. Octopus Cosy gives three off-peak windows totalling eight hours a day: 4am to 7am, 1pm to 4pm, and 10pm to midnight. Those windows price at around 51% below the day rate. There’s a peak between 4pm and 7pm that prices around 50% above the day rate.
The model assumes the household pre-heats the home and hot water cylinder during the cheap windows, then rides through the 4pm to 7pm peak on stored warmth and stored hot water. A well-insulated home holds temperature through the peak comfortably. A leaky one fights it.
Good Energy, British Gas, EDF and others offer heat pump tariffs too, with varying structures and varying quality. Economy 7 can also work for heat pump owners willing to lean on a big hot water cylinder, though it’s less optimised than Cosy. A working smart meter is required for almost all of these.
What drives your actual running costs
In rough order of impact:
Insulation. Halving heat demand halves the bill. A solid wall detached at 20,000 kWh of annual heat demand costs roughly twice what the same house insulated to 10,000 kWh costs to heat. This is true regardless of heating system.
SCOP achieved in practice. Set primarily by flow temperature, radiator sizing, and commissioning. The badge SCOP on the heat pump is a lab figure. What you actually achieve is a function of how the system is designed and set up. The HeatPumpMonitor.org real-world average across 252 monitored UK air source installs sits at around 3.87 as of January 2026. The older Electrification of Heat trial figure of 2.8, still used in some government modelling, reflects an earlier generation of installs.
Flow temperature. Every 1°C of unnecessary flow temperature costs roughly 2.5% of efficiency. An installer setting the flow at 55°C when the system would run fine at 45°C is leaving roughly 25% of your efficiency on the table.
Tariff.
Hot water demand. A family of four with daily showers uses materially more electricity for hot water than a single occupant.
Thermostat habits. Heat pumps prefer to run continuously at a low flow temperature rather than blast on and off. Treating one like a gas boiler hurts running costs.
The shape of costs across the year
Roughly 80% of space heating energy is used between October and March. January and February are the most expensive months. A 3-bed semi in a sustained cold snap on a standard tariff can see daily costs of £5 to £8 for heating alone. Summer costs are mostly just hot water, often £20 to £40 a month.
This matters for two reasons. First, anyone who switched on a heat pump in April hasn’t seen their real winter bill yet. Second, monthly direct debits average out across the year. The bill shock comes when people read meters in February.
Air source vs ground source running costs
Ground source heat pumps typically achieve SCOP 4.0+ because soil temperature is stable and warmer than UK winter air. That generally means annual running costs 15% to 25% lower than an equivalent air source install. The installed cost gap (often £10,000+ more for ground source, including borehole or trench work) is rarely justified by running cost savings alone over a reasonable timeframe. For very large or poorly insulated properties the gap can narrow, particularly if a standard air source unit would struggle to size up.
A note on standing charges
Electricity standing charges still apply. Under the Q2 2026 cap, that’s around 57p a day. If the gas supply is fully disconnected (not just unused), the gas standing charge of around 29p a day comes off the bill, saving roughly £100 a year. Some households keep gas for cooking, which keeps the standing charge in play.
FAQ
How much does a heat pump cost to run per year?
A well-installed system in a 3-bed semi costs roughly £900 to £1,200 a year on a standard tariff at Q2 2026 prices, or £450 to £700 a year on a heat pump tariff. Flats run lower, detached homes run higher.
Are heat pumps cheaper to run than gas boilers?
On a standard variable tariff with a SCOP around 3.0 to 3.2, a heat pump is broadly cost-neutral against a modern gas boiler. On a heat pump tariff, savings of £200 to £500 a year are realistic for most homes. At SCOP 4.0+, heat pumps beat gas on a standard tariff too.
What is the cheapest tariff for a heat pump?
Octopus Cosy is currently the most popular dedicated heat pump tariff in the UK, with three off-peak windows totalling eight hours a day at around 51% below the day rate. Good Energy, British Gas, and EDF also offer heat pump tariffs. The right one depends on your usage pattern and whether you have solar or a battery.
Do I need a smart meter for a heat pump tariff?
Yes, in almost all cases. Heat pump tariffs are time-of-use tariffs, so the supplier needs half-hourly consumption data.
How much electricity does a heat pump use?
A 3-bed semi with annual heat demand of around 12,000 kWh and a SCOP of 3.2 will use roughly 3,750 kWh of electricity for heating and hot water. A 1-bed flat might use 2,000 to 2,500 kWh. A 4-bed detached can easily hit 5,500 kWh or more.
Why is my heat pump so expensive to run?
The usual culprits are high flow temperature, undersized radiators forcing the system to compensate, poor commissioning, a standard variable tariff when a heat pump tariff would suit, or a property with worse insulation than the heat loss survey assumed. A SCOP below 2.5 in a metered install is a red flag worth investigating.
What SCOP should I expect from an air source heat pump?
The HeatPumpMonitor.org average across 252 monitored UK installs sits at around 3.87 (January 2026). A well-designed, low-flow-temperature system in a reasonably insulated home should achieve 3.2 to 4.0. Anything below 2.8 suggests something is wrong with the design, commissioning, or flow temperature.
Do heat pumps cost more to run in winter?
Yes, sharply. Around 80% of space heating energy is used between October and March. January and February are typically the most expensive months, with daily costs of £5 to £8 not unusual for a 3-bed semi on a standard tariff in a cold snap.
Are ground source heat pumps cheaper to run than air source?
Usually yes, by 15% to 25%, because ground source systems typically achieve SCOP 4.0+ thanks to stable soil temperatures. The installed cost premium is rarely recovered through running cost savings alone.
Does insulation make a big difference to heat pump running costs?
A very big difference. Halving heat demand halves running costs. Insulation upgrades also let the heat pump run at a lower flow temperature, which lifts SCOP and compounds the saving.
Can solar panels reduce heat pump running costs?
Yes, particularly for the hot water side and shoulder-season heating. The catch is that heat pump demand peaks in winter when solar output is lowest. Solar generally cuts annual electricity use by 10% to 25% for a heat pump household, more with a battery.
Is it cheaper to run a heat pump on Economy 7?
It can work, particularly with a well-insulated hot water cylinder used to store heat during the cheap overnight window. Dedicated heat pump tariffs like Cosy usually beat Economy 7 for heat pump owners because the off-peak windows align better with daytime heating needs and there’s no expensive overnight standard rate to worry about.