Question 1

How much electricity does a heat pump use?

Accepted Answer

A typical UK household heat pump uses around 3,000–5,000 kWh of electricity a year. The exact figure depends on your home's heat demand and the seasonal coefficient of performance (SCOP) of the installation. A well-designed system in an insulated home might use 3,000 kWh; a large, poorly insulated home can exceed 6,000 kWh.

Question 2

Is a heat pump cheaper to run than a gas boiler?

Accepted Answer

It depends. If your SCOP is 3.0 or above, gas is around 6–7p/kWh and electricity is around 27p/kWh, running costs are usually comparable. On a specialist heat pump tariff, or with solar contribution, a heat pump often becomes cheaper. In a poorly insulated home with a high flow temperature, a heat pump can cost more to run than gas.

Question 3

What SCOP should I use in the calculator?

Accepted Answer

Air source heat pumps in well-designed UK installations typically achieve a SCOP of 2.8–3.8. Ground source can reach 3.5–4.5. Use 3.0 as a sensible default for a modern air source system on 45°C flow. Use 2.5 or lower if radiators run hot (55°C+) or the property has poor insulation.

Question 4

What electricity tariff is best for a heat pump?

Accepted Answer

Specialist heat pump tariffs (like Octopus Cosy, OVO Heat Pump Plus and E.ON Next Heat Pump) offer discounted rates during heating hours, often 20–23p/kWh average. A standard flat-rate tariff at 27p+ makes running costs less competitive.

Question 5

Does a heat pump work in an older home?

Accepted Answer

Yes — most older UK homes can be heated with a heat pump, but the economics depend on flow temperature. Older homes often need larger radiators or underfloor heating to run at 45–50°C flow and hit a decent SCOP. A proper MCS heat-loss survey is essential.

Question 6

How does flow temperature affect heat pump cost?

Accepted Answer

Every 5°C rise in flow temperature reduces heat pump efficiency by roughly 5–10%. A system designed for 35°C flow can achieve SCOP 4.0+; one running at 55°C might struggle to hit 2.5. Lower flow temperature = lower running cost.

Question 7

Can solar panels reduce heat pump running costs?

Accepted Answer

Solar can offset a portion of heat pump electricity, but winter solar generation is low precisely when heat demand is highest. In practice, expect solar to cover only 10–20% of annual heat pump electricity in most UK homes, not 50%.

Question 8

Should standing charges be included in the comparison?

Accepted Answer

By default we compare running costs only. Standing charges rarely change because most homes keep an electricity connection anyway. Only include a gas standing charge saving if you plan to fully disconnect from the gas network.

Question 9

Are heat pump running-cost estimates accurate?

Accepted Answer

This calculator is designed to give a realistic estimate within roughly ±20% for typical UK homes. Actual performance depends on installation quality, radiator sizing, weather compensation, controls and occupant behaviour. Only a proper MCS heat-loss survey and a monitored installation can give a precise figure.

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