What else do you want to include in the balance besides a towel radiator in a bathroom with underfloor heating? Or should all bathrooms generally be at least 20 sqm in size so that the heating loops of the underfloor heating are sufficient to achieve the necessary room temperature?
If the underfloor heating is not sufficient to cover the room heating load, I usually provide an
additional radiator. Overall, of course, depending on the necessary, chosen system flow temperature. In some cases, the bathroom with underfloor heating and/or radiator is heated to, for example, 20..21°C, while the short-term peak demand up to 24°C is covered by infrared heaters. If a towel radiator is included in the balance, it can only effectively contribute to the required heating load if its heat output is
not hindered by towels. Otherwise, the flow temperature or mass flow may need to be increased, which is not in the interest of maximum energy efficiency. This applies especially to heat pumps as heat generators.
Regards