Where do the default prices come from?

DESNZ Quarterly Energy Prices, September 2026 edition (published 29 September 2026): Q2 2026 all-non-domestic average electricity 24.51p per kWh and gas 5.28p per kWh, excluding VAT. They are national averages across all non-domestic users, so replace them with your own rates.

What SCOP should I enter?

Use a design figure from a quote, with the conditions it assumes. Seasonal efficiency depends on flow temperature, controls and the climate. See SCOP explained .

Does it include the Boiler Upgrade Scheme or tax relief?

No. The Boiler Upgrade Scheme applies to heat pumps up to 45 kW thermal in small non-domestic buildings; tax relief is the Annual Investment Allowance and, above that, the 50% first-year allowance for companies. See grants and funding .

Why is the kW figure only indicative?

It divides annual heat by equivalent full-load hours, which is a screening shortcut. Real sizing uses the building’s peak heat loss and demand profile; see the air-source guide .

Commercial heat pump running-cost calculator

Enter your fuel use and tariffs to see whether a heat pump at a given SCOP would cost more or less to run than your boiler, and the SCOP it needs to break even.

Independent information, not installer advice. Last reviewed 3 November 2026. Sources are linked in the text.

Use your bills rather than the defaults wherever you can. Electricity price is the biggest lever: a negotiated or time-of-use tariff, or on-site generation that covers part of the heat pump’s load, can lower the effective rate and the break-even SCOP.

Indicative only. This calculator compares energy cost per year using the prices and efficiencies you enter. It is not a quote, a design or tax advice. The pre-filled prices are DESNZ Quarterly Energy Prices (September 2026 edition) Q2 2026 averages across all non-domestic users (electricity 24.51p/kWh, gas 5.28p/kWh, excluding VAT). Replace them with the rates on your own bills: national averages hide a wide spread. At these figures and an 88% boiler the break-even SCOP is about 4.1.

-Heat delivered per year (kWh)

-Gas (or oil) boiler running cost

-Heat pump running cost at the SCOP entered

-Annual difference (positive = heat pump cheaper)

-Break-even SCOP on energy cost

-Indicative peak load (kW thermal, screening)

What is missing. Standing and capacity charges, maintenance, capital cost, grants (the Boiler Upgrade Scheme is limited to 45 kW thermal for a single heat pump and 70 kW thermal for a multi-unit system), tax relief, any change to your electricity connection, and the carbon effect. For the first-year tax route see the grants and funding guide.

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Commercial heat pump running-cost calculator

Calculator questions

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Sources