Cooling load
A first-pass air-con size from floor area and watts per square metre.
Open a calculatorHeat pump
Heat is floor area times a planning figure in kWh/m²·year. Electricity is that heat divided by the seasonal COP you enter. Gas uses the same heat divided by boiler efficiency. The insulation classes are sketches (an old house around 160 kWh/m², a WT 2021 house around 45), not an energy certificate and not a heat-loss survey.
Heated floor area — exclude garage, cellar and unheated attic; often 80–150 m² in a house.
Heated floor area — exclude garage, cellar and unheated attic; often 80–150 m² in a house.m²
Planning heat demand per m² per year — not an energy certificate or heat-loss survey.
Planning heat demand per m² per year — not an energy certificate or heat-loss survey.Average heat-pump SCOP over the heating season — often 3–4; direct electric heat is effectively 1.
Average heat-pump SCOP over the heating season — often 3–4; direct electric heat is effectively 1.Gas energy price per kWh of fuel — not your m³ bill; convert from the tariff.
Gas energy price per kWh of fuel — not your m³ bill; convert from the tariff.Boiler efficiency for the gas comparison — a modern condensing boiler is often 0.85–0.92 as a fraction (0.9 = 90%).
Boiler efficiency for the gas comparison — a modern condensing boiler is often 0.85–0.92 as a fraction (0.9 = 90%).Heat-pump year
3,086 zł
Heat delivered
12,000 kWh
Electricity used
3,429 kWh
Gas-boiler year
4,667 zł
Gas year minus heat-pump year
1,581 zł
Heat-pump year: 3,086 zł
Domestic hot water, a buffer tank and the defrost cycle are not in the year. A real SCOP depends on the emitter temperature and the climate. This is not a grant application.
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An educational estimate. Not medical, tax or credit advice.