A heat pump can heat the water up to 60 ° C, But we recommend not to exceed 55 ° C.
Old radiator systems are usually sized to operate at 65-70 ° C. Therefore it is possible to use the heat pump in the mid seasons and on less cold days.
If instead the radiators are designed to operate at 50 ° C or even less (by increasing the number of elements or lengthening the time of heating), the heat pump will be usable without the aid of external sources and ensure savings interesting than the boiler, Quantifiable between the 20% and 40%.