Heat pump running costs in the UK are widely misunderstood — often quoted too high by sceptics, too low by installers with a sales pitch to deliver. This post cuts through the noise with real calculations using current energy prices, based on what UK homes actually consume. The headline figure for a 3-bedroom semi-detached home is £900–£1,400 per year in electricity for heating and hot water — but where you land in that range depends on several factors this post unpacks.
Key Takeaways
- A typical 3-bedroom UK home costs £900–£1,400/year to heat with a well-installed air source heat pump at current energy prices.
- The key driver is your heat pump’s Seasonal COP (SCOP) — the UK average is around 2.8 (Nesta 2023 field trial data).
- At a CoP of 2.8 and 25p/kWh electricity, heat costs 8.9p per kWh — compared to ~6.7p for mains gas at 90% boiler efficiency.
- A smart tariff (e.g. Octopus Go at 7p/kWh overnight) can cut heat pump running costs by 30–40%, making them cheaper than gas.
- Running costs drop significantly with better insulation and lower flow temperatures — the two biggest levers you control.
- Annual servicing costs around £100–£200 — less than a gas boiler service, with no flue gas or carbon monoxide checks required.
The Key Number: Heat Pump Coefficient of Performance (CoP)
A heat pump’s running cost is driven by its Coefficient of Performance (CoP) — the ratio of heat output to electricity input. A CoP of 3 means 3kWh of heat delivered for every 1kWh of electricity consumed. The seasonal figure (SCOP or SPF) averages this across the whole year including cold weather when efficiency dips.
Nesta’s 2023 field trial of 742 UK homes found an average seasonal performance factor of 2.8 for well-installed air source heat pumps. Top-performing homes with good insulation and underfloor heating hit 3.5–4.0. Poorly installed or badly configured systems dropped to 2.0–2.2.
What this means in pounds: at Ofgem’s current electricity price cap rate of approximately 25p/kWh, each unit of heat costs:
- At CoP 2.0 (poor system): 12.5p per kWh of heat
- At CoP 2.8 (average): 8.9p per kWh of heat
- At CoP 3.5 (good system): 7.1p per kWh of heat
- Gas boiler at 90% efficiency (for comparison): 6.7p per kWh of heat
At today’s electricity and gas prices, a well-performing heat pump is very close to gas on cost per unit of heat. A poorly installed one is noticeably more expensive. This underlines the importance of installation quality — the same technology can look very different on your bills depending on who fitted it and how well.
Annual running costs by home size
These estimates assume an air source heat pump with a SCOP of 2.8, electricity at 25p/kWh, and typical UK heat demand figures from the Energy Saving Trust:
| Home type | Annual heat demand | Electricity consumed (SCOP 2.8) | Annual cost at 25p/kWh |
|---|---|---|---|
| 1–2 bed flat or terraced (well insulated) | 7,000 – 10,000 kWh | 2,500 – 3,600 kWh | £625 – £900 |
| 3-bed semi-detached | 12,000 – 16,000 kWh | 4,300 – 5,700 kWh | £1,075 – £1,425 |
| 4-bed detached | 16,000 – 22,000 kWh | 5,700 – 7,900 kWh | £1,425 – £1,975 |
| Large detached or poorly insulated | 22,000 – 30,000 kWh | 7,900 – 10,700 kWh | £1,975 – £2,675 |
These are heating and hot water costs only — they don’t include general household electricity. Add your normal electricity bill on top. Most 3-bedroom households spend roughly £1,000–£1,400 per year on the heat pump element, which is comparable to or slightly higher than a modern gas boiler at current prices.
How heat pump running costs compare with gas, oil, and LPG
| Fuel type | Approx. price per kWh (2026) | Boiler efficiency | Effective cost per kWh heat | Annual cost (3-bed) |
|---|---|---|---|---|
| Heat pump (electricity) | 25p | CoP 2.8 | 8.9p | £1,100 – £1,400 |
| Mains gas boiler | 6p | 90% | 6.7p | £800 – £1,100 |
| Heating oil boiler | 7.5p | 85% | 8.8p | £1,050 – £1,600 |
| LPG boiler | 12p | 85% | 14.1p | £1,700 – £2,500 |
| Electric storage heaters | 25p | 100% (direct) | 25p | £3,000 – £5,000 |
This table makes clear why heat pumps are particularly compelling for LPG and electric storage heater households — the running cost reduction is substantial. For gas homes, the difference is smaller, and the case rests more on the grant and the long-term direction of energy prices. Our is a heat pump worth it analysis goes into this in more depth.
How to reduce your heat pump running costs
Running costs aren’t fixed — they can be significantly reduced with the right approach:
1. Use a heat pump-optimised electricity tariff
Some energy suppliers offer tariffs with cheaper overnight electricity rates designed for heat pump users. Octopus Energy’s Cosy Octopus tariff provides cheaper rates during off-peak periods specifically for heat pump homes. If your heat pump has a buffer tank, it can pre-heat water overnight at a cheaper rate. At 15p/kWh off-peak instead of 25p, the annual saving on a 3-bed home is roughly £300–£400.
2. Set the right flow temperature
Every 5°C reduction in flow temperature improves heat pump efficiency by roughly 10%. A correctly sized system should achieve comfortable indoor temperatures at 45–50°C flow. If your installer has set it at 60°C or higher, ask them to review the settings once your home has been running for a few weeks.
3. Enable weather compensation
Weather compensation automatically adjusts flow temperature based on outside air temperature — running cooler on mild days and warmer only when it’s very cold. This is one of the most effective energy-saving settings on a heat pump and should be enabled by your installer during commissioning.
4. Improve your home’s insulation
Less heat lost through walls, roof, and windows means less heat your pump needs to produce. Loft insulation alone can cut heat demand by 15–25% in an uninsulated home. Combined with a well-tuned heat pump, that’s a meaningful dent in your annual bill.
5. Add solar panels
Solar PV generates free electricity during daylight hours. In spring and autumn — when your heat pump is working but the weather isn’t too cold — you can run the heating primarily on solar generation. A 4kWp solar array on a south-facing roof can offset 800–1,200kWh of heat pump electricity annually, saving roughly £200–£300/year at current prices.
What about servicing costs?
Annual heat pump servicing typically costs £100–£200, comparable to a gas boiler service. This should include checking refrigerant pressure, cleaning filters, inspecting electrical connections, and verifying control settings. Some manufacturers and larger installers offer annual service contracts from around £120/year. Factor this into your total cost of ownership calculation.
Use our savings calculator to model your specific home’s running costs and see how they compare with your current fuel bill. Our heat pump costs guide covers the full installation picture, including what factors push costs up or down.