Is a tighter installation spacing for underfloor heating not possible with gas heating?

...I understand that you have to pay for planning tasks. We are not opposed to that at all! But I would simply be interested beforehand whether it is possible or not before I make a huge fuss.

Basically, it is not a wrong decision to design heating surfaces for future heat generators with reasonably low flow temperatures. With the currently selected heat generator, this of course sets certain limits.

...Or whether the general contractor is just claiming something that suits him better. Is such a heat pump-optimized underfloor heating with gas condensing boiler significantly more expensive (= several thousand euros), or does it just need to be well thought out with a few technical additions?

How many thousand € more is always decided by the provider (seller of the own solution). Whether it is actually justified can only be assessed by the client ;-)

best regards