Radiator calculator for heat pumps
Find out whether your radiators will cope with a lower supply temperature and what length of K11, K22 or K33 you would need.
Results are indicative and are not a heating design. Consult an installer before replacing radiators or changing your heating system.
How we calculate
A radiator’s output depends on the temperature difference between the water and the room (the EN 442 logarithmic mean temperature difference). A lower supply temperature means lower radiator output, but the heat pump works more efficiently (higher COP). The calculator shows how much output your radiator would lose, the lowest supply temperature it can still manage, and what length of panel radiator you would need.
FAQ
Will my cast-iron radiators work with a heat pump?
Often yes, if the building is insulated. Enter your details to see the supply temperature they need.
Why K22 instead of K33?
A longer K22 often does the same job as a pricier K33, if you have space on the wall.