TGA planner difficulties, underfloor heating supply temperature + wastewater ventilation

Making a developer enthusiastic about a wall heating system is almost certainly impossible.

Check it off, move on. If you have the opportunity to look at the implementation in the bathroom, definitely do so and insist on corrections if someone has fallen back into the standard out of habit during implementation.

maybe an option to just lay the supply and return lines each and leave them "capped off" at the HKV? (for retrofitting yourself) We did it this way for a possibly to be retrofitted heating system in the attic, but not through the developer / general contractor, rather individual contracting

Nice idea, but who tears down an entire wall again, meaning removing tiles, taking off plaster, installing pipes, replastering, retiling, just to save €2.95 in heating costs per year?

to : In both bathrooms there is then a 5cm installation gap. This results in the bathrooms being set to 23°, although this leads to an overlap in the guest bathroom. Electric towel radiators are additionally present in both bathrooms.

Thanks for the info. Then I would be, as mentioned, more than satisfied under the given circumstances.

You obviously won’t reach the 23° later if you turn down the flow temperatures. An overlap in the guest bathroom is therefore just right. I don’t think much of towel radiators. They have hardly any warming effect. If you want to get the efficiency out, then look around for fan heaters or similar. If the bathroom is later at 22 or 21.5 degrees, turn on the fan heater for 2 minutes if it is really too cold for you and you will have 23 degrees. The energy consumed in doing so is almost negligible. Much is always subjective perception anyway. If you jump straight under the shower, you’ll be warmer again afterwards anyway...

It will be important after handover to familiarize yourself with the system and optimize it. Possibly lower the flow temperature, disconnect all ERR, balance, deactivate pressure relief valve if available, etc...

You obviously won’t reach the 23° later if you turn down the flow temperatures. An overlap in the guest bathroom is therefore just right.
I don’t think much of towel radiators. They hardly have any warming effect.

I completely agree. However, we did retrofit an electric towel radiator after all.
Without it, the shower towels simply wouldn’t dry well.
It also helps to reduce moisture during the transitional period because it’s already a bit warmer and the moisture is better absorbed by the air and ventilated out. It usually only runs at midday with free photovoltaic electricity. ;)

I completely agree. However, we did retrofit an electric towel radiator after all.
The shower towels just couldn’t get properly dry without it.
It also helps reduce moisture during the transitional period because it’s simply getting a bit warmer and the moisture is better absorbed and ventilated by the air. It usually only runs at midday with free photovoltaic electricity.

I understand the approach. I wasn’t paying attention to whether the OP has ventilation (or you ) but with ventilation, moisture shouldn’t be a problem.

And I don’t know what kind of kilowatt monsters you have as towel radiators, but for "ordinary" ones they really don’t have much heating power and if they do, they consume a lot.

I hope you don’t really believe your last sentence about free photovoltaic electricity!? :p
That costs you at least the feed-in tariff and possibly VAT, and in winter you’re already using whatever comes from the photovoltaic system (if anything comes at all) with your heat pump or base load.

I’d rather resort to the fan heater.