Hot water calculator
Heat pump or electric boiler? Enter the number of people in your household and the electricity price, and we will show what hot water costs.
Results are indicative and are not a heating design. Consult an installer before replacing radiators or changing your heating system.
How we calculate
From the number of people (50 l of hot water per person per day by default) we find the heat needed: litres × 1.163 Wh/l·K × (hot minus cold water temperature). A resistive boiler produces that heat 1:1 (with standing losses), so it needs the same amount of electricity. A heat pump with a COP of 2.5–3 uses 2.5–3 times less electricity.
FAQ
Where do I find the heat pump kWh for hot water?
In the heat pump monitoring (hot water cycle) or a separate meter. If you do not know it, we use an indicative COP.
Why does the heating element power matter?
It shows how many hours per day the element would run. It does not change the amount of electricity used.