WattPayback
Calculator

Heat pump vs. gas boiler running cost

Compare annual running costs using heat demand, SCOP, boiler efficiency, unit rates and standing charges.

Your situation

kWh/yr
€/kWh
€/kWh

Defaults are starting points from typical published ranges — never facts. Change any value that does not match your situation.

SCOP
fraction
€/yr
€/yr

Estimate only. Based on the assumptions you entered. Get a site-specific survey before spending money.

Heat pump annual cost

€960

3,429 kWh electricity

Gas boiler annual cost

€1,484

13,636 kWh gas

Annual difference

€524

heat pump cheaper

Break-even elec/gas ratio

3.08

SCOP × efficiency; your ratio 2.80

Formula with your numbers

hp_cost = 12000 / 3.5 × 0.28 + 0 = €960

boiler_cost = 12000 / 0.88 × 0.1 + 120 = €1,484

break_even_ratio = 3.5 × 0.88 = 3.080

Frequently asked questions

What is the SCOP-to-price-ratio rule?+

A heat pump is cheaper to run than a gas boiler when electricity_price / gas_price < SCOP × boiler_efficiency (roughly). That break-even ratio is shown in the results.

What SCOP should I use?+

Air-source heat pumps often land around 2.8–4.0 seasonal COP depending on climate and design temperature. Ground-source can be higher. Use the SCOP from a proper heat-loss design, not a marketing peak COP.

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