The maximum heating output of underfloor heating systems is directly related to the maximum permissible surface temperature:
In living areas, the maximum surface temperature is 29 °C.
In bathrooms, it can be up to 33 °C.
Calculation Basis
The calculation of the maximum heating output is based on the following formula:
HL = 8.92 × (surface temperature – room temperature)^1.1
Bathroom radiators are generally not intended to cover the full heating load of a room. Instead, they serve primarily aesthetic and functional purposes — for example, for drying towels.
For this reason, we do not evaluate bathroom radiators based on supply and return temperatures, but solely based on their maximum achievable output.
Calculation Basis
As a reference, we use the standard output as defined in the technical literature by Recknagel, based on a temperature level of 75/65/20 °C.
In addition, we apply a general performance reduction of 50% to realistically account for the impact of towels hanging on the radiator.