Heat pump payback calculator

The calculator compares your current heating cost with the cost of heating with a heat pump. A heat pump produces several kilowatt-hours of heat from one kilowatt-hour of electricity – how many is shown by the seasonal coefficient of performance (SCOP). In the Estonian climate, an air-to-water heat pump typically has a SCOP of about 2.5–3.5 and a ground source heat pump 3.5–4.5 (depending on the model, heating system temperature and how cold the winter is – see the manufacturer’s data sheet).

How is it calculated?

1. Heat demand = current fuel amount × energy content × boiler efficiency. We use approximate typical values: electricity 1 kWh = 1 kWh of heat; gas (billed in kWh) 90% efficiency; light heating oil ~10 kWh/l, 85%; wood pellets ~4.8 kWh/kg, 85%; dry mixed firewood ~1,500 kWh per stacked cubic metre, 70%; district heating (billed in MWh) 100%.
2. Heat pump electricity use = heat demand × coverage ÷ SCOP. If the pump does not cover everything (e.g. an air-to-air heat pump does not heat tap water), the rest stays with the old heating.
3. Payback time = when the savings cover the investment minus any grant; energy prices grow at the chosen rate.

The line “savings disappear if electricity costs more than …” shows how expensive electricity can get before the heat pump stops saving. The calculation does not include maintenance, increasing the grid connection capacity or remaining fixed costs of the old heating. If you have solar panels, a heat pump reduces the share of electricity bought from the grid – see the solar payback calculator.