Heat Pump Running Costs vs Gas Boiler UK

On a standard tariff, a well-installed heat pump costs roughly the same as gas — within 5–15%. Switch to an off-peak tariff and the heat pump becomes 50–65% cheaper. Here are the real numbers.

Both sides of this debate make bold claims. This guide provides honest, current numbers for real UK scenarios — no cherry-picking, no best-case fantasy figures.

The Key Numbers: Energy Prices in 2026

Running cost calculations start with fuel prices. As of Q1 2026 under the Ofgem price cap:

This ratio is critical. A heat pump must produce at least 3.27 kWh of heat for every 1 kWh of electricity just to break even with gas. Anything above that and the heat pump is cheaper. This is the honest framework for all the numbers that follow. For the full cost picture beyond running costs, see our comprehensive heat pump cost guide.

What Efficiency Do Heat Pumps Actually Achieve?

The Electrification of Heat Demonstration Project (monitoring thousands of UK installations) provides the most reliable real-world data:

• Air source heat pumps (average SCOP): 2.8–3.2
• Well-installed ASHP with weather compensation: 3.2–3.6
• Poorly installed or high-temperature ASHP: 2.0–2.5
• Ground source heat pumps (average SCOP): 3.5–4.2

The variation is enormous — a well-designed system can be 50–70% more efficient than a poor one. Installation quality, flow temperature, and weather compensation settings are the main determinants. Read our installation guide to understand what good installation looks like.

Running Cost Comparison by Property Type

Annual running costs for heating and hot water at 2026 Ofgem rates:

On a standard tariff, a well-installed air source heat pump (SCOP 3.2+) is roughly 5–15% cheaper to run than gas. A poorly installed one (SCOP 2.8 or below) can be more expensive. A ground source heat pump is consistently 25–35% cheaper.

The Game-Changer: Off-Peak and Heat Pump Tariffs

The comparison changes dramatically with an off-peak or time-of-use electricity tariff:

With an off-peak tariff, the heat pump is 55–65% cheaper to run than gas. The annual saving of £550–£640 means a heat pump pays back its additional cost in 5–10 years. Pairing with solar panels can reduce daytime electricity costs further.

Standing Charges: The Hidden Factor

If you switch from gas to a heat pump and come off the gas grid entirely, you save the gas standing charge (£117/year). If you stay on gas for a hob, you pay both standing charges. For homeowners who can disconnect from gas entirely, the saving adds £117/year to the heat pump’s financial advantage.

What About Older Gas Boilers?

Maintenance Costs: Heat Pump vs Gas Boiler

• Gas boiler annual service: £80–£150
• Gas boiler repairs (averaged): £100–£200/year
• Heat pump annual service: £100–£200
• Heat pump repairs (averaged): £50–£100/year

Heat pumps have fewer moving parts and no combustion. The maintenance cost advantage is modest — perhaps £100–£150/year — but adds up over 20 years. See our maintenance cost guide for detail.

The Honest Bottom Line

• On a standard electricity tariff: A well-installed heat pump costs roughly the same as gas — within 5–15%.
• On an off-peak tariff: A heat pump is 50–65% cheaper than gas. This is where the genuine financial case lies.
• Installation quality matters enormously: The difference between SCOP 2.8 and 3.5 is 25% more electricity.
• Tariff choice matters as much as heat pump efficiency.

For the broader comparison including installation costs and payback, see our heat pump vs gas boiler guide.

How to Minimise Your Heat Pump Running Costs

1. Get on a heat pump or off-peak tariff — can halve your running costs.
2. Ensure weather compensation is active — automatically optimises efficiency.
3. Keep flow temperatures as low as possible — aim for 35–45°C.
4. Insulate your property — less heat loss means less electricity.
5. Set hot water efficiently — 48–52°C for storage, legionella cycle once or twice weekly.
6. Do not override automatic controls — trust the system.

Frequently Asked Questions

Are heat pumps more expensive to run than gas boilers?

On a standard electricity tariff, a well-installed heat pump runs at roughly the same cost — within 5–15%. On an off-peak tariff, a heat pump is 50–65% cheaper.

Will heat pump running costs decrease in the future?

Likely yes. The UK government has committed to rebalancing electricity and gas prices. When this happens, the electricity-to-gas price ratio should fall.

What electricity tariff should I choose with a heat pump?

Look for tariffs with low overnight rates. Time-of-use and heat pump-specific tariffs can offer overnight rates of 8–15p/kWh.

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

For a typical 3-bed semi on a standard tariff: roughly £75–£85/month averaged over the year. On an off-peak tariff: approximately £35–£45/month.

Does a heat pump use more electricity than I currently use?

Yes — your electricity consumption increases by 3,500–4,500 kWh/year for a typical 3-bed semi. But your gas consumption drops to zero, so total energy cost is what matters.

Is a heat pump cheaper than gas for hot water?

Hot water heating is roughly comparable on a standard tariff and cheaper on an off-peak tariff. The heat pump heats water at COP 2.5–3.5.