Smarter Heating & Hot Water

Heat Pump COP Breakeven Calculator

Boiler vs heat-pump running cost: the COP a heat pump needs to match a gas boiler, then the saving (or extra cost) at a chosen COP.

Electricity Price £/kWh 0.27
Gas Price £/kWh 0.0678
Boiler Efficiency 0.90
Annual gas used for heating kWh 12,000
Heat Pump COP 2.8
Electric / Gas Ratio
—
Breakeven COP
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Heat pump vs boiler
—
How far the COP is from breakeven. Positive costs more to run.
Annual heating cost difference
—
Uses the gas the boiler burns for heating. Positive costs more. Standing charges are separate.

Formula

Ratio = Electricity ÷ Gas
Breakeven COP = Ratio × Boiler efficiency
COP gap % = ((Breakeven COP − Heat-pump COP) ÷ Breakeven COP) × 100
Boiler cost = Gas used × Gas price
Heat pump cost = (Gas used × Boiler efficiency ÷ COP) × Electricity price

Unit rates must be the same basis (usually £/kWh). Boiler efficiency is a fraction (0.9 = 90%). A heat pump cheaper than gas needs a seasonal COP above the breakeven figure.

Important: The annual figure is the cost of the heat from the gas entered above. It does not include standing charges, heat-loss, emitter temperature, or installation cost. Information is guidance; gas work needs a Gas Safe engineer.