Gas heating capacity selection 20kW instead of 14kW

Insist on a room-wise heating load calculation according to DIN xxx

You can also commission this on the internet at an engineering firm – costs about 300€. My heating installer didn’t want to do it and so far the agreement is that I will do it and he will implement the result as my own contribution.

Insist on a room-specific heating load calculation according to DIN xxx

Since it is an additional service for me (new radiators), the company will probably not do that. One could have the pipes pre-installed and then do the connection afterwards oneself.

What is it all about? New construction/expansion/renovation?

The basement rooms are already finished?

What is it about anyway? New build/extension/renovation? Are the basement rooms already finished?

New build, the basement rooms are structurally finished, yes. As described in the first post, it concerns two new radiators, which is why the company wants to increase the service. If I don’t have them installed, the service remains the same.

And which part of the warranty are you supposed to waive? That the house does not get warm enough, or the entire warranty?

Is the rest all underfloor heating and is it only about the basement? If it’s about the radiators and the higher supply temperature required for them, you can also install underfloor heating in the basement. Costs would be the heating circuit distributor and a few hundred euros for the pipes + installation.