Costs
Heat pump running costs: how much electricity does a heat pump use?
Last updated 2026-08-18
One of the biggest worries people have about switching to a heat pump is: "Will my electricity bill go through the roof?" It's a fair question — electricity costs roughly 3.5x more per kWh than gas. But heat pumps use far less energy to produce the same amount of heat. Here's the math, made simple.
How much electricity does a heat pump use?
A typical air source heat pump in a well-insulated UK home uses between 3,000 and 5,000 kWh of electricity per year for heating and hot water. That compares to about 12,000 kWh of gas for the same home with a gas boiler.
The reason for the huge difference is efficiency. A gas boiler is about 90% efficient — it turns 1 kWh of gas into 0.9 kWh of heat. A heat pump has a COP (Coefficient of Performance) of around 3.0–4.0, meaning it turns 1 kWh of electricity into 3–4 kWh of heat. It doesn't create heat — it moves it from outside air into your home.
COP explained simply
Think of COP like miles per gallon, but for heating:
- COP 2.0 = 2 kWh of heat for every 1 kWh of electricity (poor — your heat pump is working hard, probably because it's very cold outside or your home is poorly insulated)
- COP 3.0 = 3 kWh of heat for every 1 kWh of electricity (typical for a well-installed system in average UK temperatures)
- COP 4.0 = 4 kWh of heat for every 1 kWh of electricity (excellent — mild weather, good insulation, well-sized system)
Your heat pump's COP varies throughout the year: higher in autumn/spring (milder air) and lower in deep winter (when the pump has to work harder to extract heat from cold air). The annual average is called the SCOP (Seasonal Coefficient of Performance), and a good UK installation should achieve SCOP 3.0–3.5.
Annual running costs: the numbers
| Property type | Annual kWh (electricity) | Annual cost (~27p/kWh) |
|---|---|---|
| 2-bed flat (well insulated) | 2,500–3,500 | £675–£945 |
| 3-bed semi (average insulation) | 3,500–5,000 | £945–£1,350 |
| 4-bed detached (average insulation) | 5,000–7,000 | £1,350–£1,890 |
| 4-bed detached (poorly insulated) | 7,000–9,000 | £1,890–£2,430 |
For comparison, a gas boiler in a typical 3-bed semi costs about £840/year in gas plus £115/year standing charge = £955/year. So the heat pump at ~£945–£1,350 is competitive — and remember, you also save the gas standing charge (~£115/year) if you no longer need gas at all.
How to keep your heat pump running costs low
- Insulate first — loft insulation, cavity wall fill, and draught-proofing reduce the amount of heat your home needs, which directly reduces your heat pump's electricity consumption.
- Run it like a radiator, not an on/off boiler — heat pumps are most efficient when they run continuously at a lower temperature. Don't switch it on and off; let the thermostat manage it.
- Lower your flow temperature — every 1°C you lower the flow temperature improves efficiency by about 2.5%. Ask your installer to set it as low as your home can handle (35–45°C is ideal).
- Use a smart tariff — tariffs like Octopus Agile or Cosy Octopus offer cheaper electricity at night or off-peak hours. If you have a hot water cylinder, you can heat it during cheap periods.
- Get solar panels — if you generate your own electricity, your heat pump running costs drop dramatically. Solar + heat pump is the cheapest heating combination available.
- Service it annually — a well-maintained heat pump maintains its efficiency. An unmaintained one can lose 10–25% efficiency over time.
What about in winter, when it's coldest?
A common concern is that heat pumps become inefficient in cold weather. Modern heat pumps (especially those using the newer R290 refrigerant) work efficiently down to -20°C. The COP drops in very cold weather — from ~3.5 at 10°C outside to ~2.0 at -5°C — but the pump still produces more heat than the electricity it uses. The key is having the right size system for your home's worst-case heating demand.
The bottom line
For most homes, a heat pump's running costs are comparable to a gas boiler — and significantly cheaper than oil or LPG. With the £7,500 grant making installation affordable, and the ability to pair with solar panels and smart tariffs for even lower costs, heat pumps are increasingly the cheaper option over their 15–20 year lifespan.
The best way to get an accurate estimate for your home is to get quotes from MCS-certified installers, who will calculate your expected running costs based on your property's heat demand.
Want a personalised estimate? Check your grant eligibility and get free quotes — your installer will calculate exact running costs for your property.
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