Lowering the supply temperature in underfloor heating more complex than expected?

Hi,
what does the contract allow? Do you have a contractually guaranteed right to inspect/receive this document?
The announcement of five-figure additional costs is surely intended to nip any discussion in the bud...
Regards

I recently had this discussion (reduce flow temperature to 30°C) with our general contractor as well. He said he has to calculate based on 35°C because that is what the standard requires. He must comply with this; otherwise, if the target values are not met in practice, I could take legal recourse. This likely also protects the contractor to some extent, and they are not very keen on building a house optimized to the limit, but their design must correspond to the "rules of technology" and the majority.

However, he added that it would not be a problem to reduce the flow temperature to 32°C – or even down to 30°C in milder winters – the heat pump can easily handle that, he said. He himself runs only 28° with 10cm spacing and we have similar heating loads. Oh yes, we have also planned several square meters of wall heating (heating loops) in the bathrooms, which is why I am now somewhat more relaxed about it.

So I was satisfied for the time being, since the contract entitles me to a turnkey house and I can hardly demand every calculation in detail. Personally, I don’t like it, but unfortunately, that is probably the way it is when building with a general contractor. Before signing, I didn’t really think it could become such a big issue – that is, getting more involved in the planning and construction to "optimize." Nevertheless, I would not have been better off price-wise with individual trades and probably would have had significantly more work with the project than I already do.

If I have understood some posts here correctly, 10cm spacing should be enough to be able to play with the flow temperature. Ultimately, the 35°C then only exists on paper to achieve the target room temperatures, which does not mean that those have to be the personal comfort temperatures (some people prefer only 16°C in the bedroom).

If I have correctly understood one or the other post here, a laying distance of 10cm should be sufficient to be able to play with the flow temperature.

Not only the distance is crucial, but above all also the length of the circuits.

Not only the distance is decisive, but above all the length of the circles.

Yes, these should not be too long and should not have extreme length differences, I assume that.

If the tub is in the Styrofoam box, underfloor heating underneath is rather counterproductive, as the loops reduce the flow without adding heat.

The heating output under the bathtub with Styrofoam box will certainly not be the same as with a freestanding tub. However, the heating output will not be zero, and thus this area will help to cover the necessary heat demand.

The heating output under the bathtub with the styrofoam box will certainly not be the same as with a freestanding tub. However, the heating output will not be zero, and thus this area will help to cover the necessary heat demand.

Have you calculated that, tried it out, or is that just a feeling?