Towel radiator at low flow temperature

How many square meters do the bathrooms have?

One always forgets something... Bathroom 1: 12m² Bathroom 2: 7.6m²

You always forget something...

Bathroom 1: 12m²
Bathroom 2: 7.6m²

should not cause any problems: the floor area will be large enough in both rooms!

No problem, he said, with HTHKs that are fed by our geothermal heat pump with the correspondingly low flow temperature. He said that in summer it is quite low, for example 35°C, and in winter higher, for example 45°C.

So now I have flow temperatures between 29 and 31° in the underfloor heating and thus also in the HTHK, depending on how far below 0° the thermometer was. Where does your heating get 45° from? Is there a separate circuit for the HTHK?

So I now have floor heating and thus also in the HTHK flow temperatures between 29 and 31°, depending on how far below 0° the thermometer was. Where does your heating system get 45° from? Is there an extra circuit for the HTHK?

That was a very general statement from the installer. I still have no idea what temperature will actually be present later. The heating is not installed yet. What would be the purpose of an extra circuit?

I would install the radiators and integrate them into the underfloor heating circuit. A HTHK is simply too practical as a towel holder to do without. You can live with the lower temperature. In our old house, the HTHK is integrated into the return flow of the underfloor heating (!) and of course does not get very warm, but it does help a bit and I also like it when the towels are slightly warmed.

What would be the purpose of an extra circuit?

It would probably have to be similar to mixing underfloor heating and regular radiators. Whether that even works with a heat pump or if it only works with gas, I don’t know.

For us, towel radiators were necessary because of the size of the bathroom, and we also connected them to the heat pump. Since I adjusted the heat pump based on the flow temperature after the bathroom, the radiators run at level 5 anyway. Due to the low flow temperatures, you hardly notice it. Whether the towels would be warmer hanging there because of that, I can’t say.
In the bathroom on the ground floor, I find the towel radiator quite practical. That’s where we first hang the soaked mud or winter clothes and shoes from the little one to dry.

What I find fascinating is how low the temperatures needed for heating are in such a new building with underfloor heating.
During the last heating maintenance in early January, our heating technician made a mistake with the refrigerant filling, so our heating could only heat up to a maximum of 26° flow temperature for over 1.5 weeks with outside temperatures from -5 to -15 °C. Even that was enough to maintain an indoor temperature of 20-21°. And our house is only KFW70.