Heat pump running costs in the UK

Running costs depend on three things: how much heat your home needs, the heat pump's SCOP, and your electricity tariff. Get those right and a heat pump beats a gas boiler on running cost. Get them wrong and it can be more expensive.

The running-cost formula

The three inputs:

• Heat demand: how much heat your home needs in a year, in kWh. A typical 3-bed UK semi is 11,000–14,000 kWh. An older detached house can be 18,000–22,000.
• SCOP: the heat pump's annual efficiency. Realistic UK ASHP installs are 3.0–4.0.
• Electricity price: standard variable rate per the current Ofgem cap is around 24.5 p/kWh. Time-of-use heat-pump tariffs can drop the effective average to 15–20 p.

Worked examples

Example 1: Well-insulated 3-bed semi

Annual heat demand

11,000 kWh

SCOP

3.8

Electricity (standard cap)

24.5 p/kWh

Annual running cost

£710

On a heat-pump tariff at an effective 18 p/kWh, this drops to £520/year.

Example 2: Average UK 3-bed semi

Annual heat demand

13,000 kWh

SCOP

3.3

Electricity

24.5 p/kWh

Annual running cost

£965

Example 3: Older 4-bed detached, partial retrofit

Annual heat demand

18,000 kWh

SCOP

2.9

Electricity

24.5 p/kWh

Annual running cost

£1,520

This is the case where running costs can underwhelm. SCOP under 3.0 is a sign the system is fighting the property, radiators too small, flow temperatures too high, or insulation gaps. Often fixable.

Tariffs that genuinely help

UK suppliers now offer tariffs specifically priced for heat pump owners. The headline rate is often slightly higher than standard, but the off-peak hours are much cheaper, and most heating energy is consumed when you can schedule the cylinder reheat:

• Octopus Cosy, three rate bands; ~13 p in off-peak windows that the heat pump can target.
• OVO Heat Pump Plus, flat heat-pump-only rate.
• EDF Heat Pump tracker, fixed rate dedicated to heat pump use.

Compare these against the standard cap each quarter; the gap moves.

The SCOP lever

SCOP is the single biggest factor inside your control. Improving SCOP from 3.0 to 3.8 cuts running cost by ~25%. Ways to improve SCOP:

• Lower the design flow temperature, every 5 °C reduction is worth ~10% on SCOP.
• Bigger radiators in the rooms that struggle.
• Weather compensation correctly tuned.
• Set the cylinder thermostat to 45–48 °C (with weekly Legionella cycles to 60 °C).

"Should I run it 24/7 or use a schedule?"

Heat pumps prefer steady, low-temperature output. For most homes, a gentle setback at night (1–2 °C below daytime target) and a continuous low-temperature run during the day will be more efficient than a deep timer-based schedule. The exact answer depends on insulation; many installers will recommend "set it and forget it" with weather compensation doing the work.

What heat pumps cost to run vs gas boilers

On the same 13,000 kWh heat demand, an 88%-efficient gas boiler uses ~14,800 kWh of gas at 6.0 p/kWh (current cap) for an annual cost of £890. The heat pump at SCOP 3.3 costs £965 on standard cap, £660 on a heat-pump tariff. The gap moves with energy prices, gas/electric ratios have widened and narrowed several times since 2021.

See our full heat pump vs gas boiler comparison for a 15-year total cost view.

How weather actually affects your bill

A cold snap doesn't just increase heat demand, it can also lower SCOP temporarily, because the compressor works harder to lift heat from colder outside air. A week of −5°C nights can push the effective running cost for that week up by 30 to 40% compared with a mild week at 8°C, even though the heat pump itself hasn't changed. This is normal and expected, don't judge a heat pump's overall performance from one cold snap, look at the whole heating season (October to April) when comparing against a previous gas bill.

Comparing your bill against last year's gas

The fairest comparison is heating-season to heating-season, not month to month, since gas boilers and heat pumps distribute consumption differently across the year. Pull your gas usage in kWh (not pounds, since gas and electricity prices move independently) from October to April of your last gas-heated winter, then compare it against your heat pump's electricity use for the equivalent months this year. If your heat pump used more electricity than the formula above predicts, the likely causes are a lower-than-designed SCOP, a hot water cylinder set too high, or draughts and heat loss that weren't accounted for in the original survey.

Monitoring your own running costs

Most heat pump controllers log electricity consumption, and a growing number integrate with a home energy monitor (or a smart meter's in-home display) to show cost in pounds rather than kWh. Check your figures against the worked examples above after the first full month, if your actual cost is more than 20% above the equivalent example, it's worth asking your installer to check the flow temperature and weather compensation settings before assuming the technology itself is the problem.

Hot water's share of the bill

Space heating dominates a UK heat pump's electricity use, but hot water still matters. A typical household's domestic hot water demand runs to roughly 2,000 to 3,000 kWh a year, heating a cylinder to 45 to 48°C daily plus a weekly Legionella cycle to 60°C. At a SCOP nearer 2.5 for hot water (lower than space heating SCOP because of the higher target temperature), that's broadly £200 to £350 a year on a standard tariff. It's a smaller slice than heating, but not negligible, and it's fixed regardless of how mild the winter is, worth remembering when a summer bill still shows meaningful electricity use.

Standing charges and the bigger bill picture

Running-cost comparisons usually focus on the per-kWh maths, but standing charges matter too. If you remove your gas supply entirely after switching to a heat pump, you drop the gas standing charge, typically £100 to £130 a year, on top of the running cost savings from a good tariff. Most households keep a gas connection for cooking during the transition, so this saving isn't automatic, factor it in only if you're genuinely going all-electric.

Solar panels and battery storage

If you already have solar PV, or you're considering it alongside a heat pump, the running-cost picture shifts further. Heat pump electricity use skews toward autumn and winter, exactly when solar generation is lowest, so panels alone won't cover much heating demand directly. A battery charged overnight on a cheap tariff rate can still meaningfully reduce your effective daytime electricity cost, and some heat-pump-friendly tariffs are specifically designed to work well with battery storage. It's a genuine optimisation worth discussing with your installer, but not one that changes the core running-cost maths in this guide, it's a layer on top, not a substitute for a well-sized heat pump on a sensible tariff.

If you're weighing solar and a heat pump as a combined project, sequencing matters more than most people expect: get the heat pump's heat-loss survey done first, since the resulting design informs how much electrical capacity you'll have left for solar and battery charging, and some installers offer a genuine discount for specifying both at once rather than as two separate projects months apart.

Tracking your running costs over the first year

Keep a simple monthly log of electricity use for the first full heating season, October through April, alongside outside temperature if your smart meter or app tracks it. This is the single most useful thing you can do to catch an underperforming install early: a pattern of costs consistently above the worked examples here, once you've accounted for genuinely cold weeks, is worth raising with your installer well before the warranty period runs out rather than assuming it's normal. A short note with dates, readings and outside temperature makes any follow-up conversation with your installer far more productive than a vague sense that the bill "seems high".