Are cast iron radiators compatible with heat pumps?

Cast iron radiators are not only compatible with heat pumps, they can be a highly efficient pairing. The thermal properties of cast iron means that it heats gradually and retains the heat for a long time, which is beneficial for heat pump systems which operate in a similar way. To make the most of this pairing, consider a modern high-temperature heat pump, which operates at temperatures of up to 65–75°C.