Whom to entrust with the room-wise heating load calculation?

The problem is that most heating installers design according to DIN 12831 and thus make it too large. As a result, the heat pump does not necessarily operate in the efficiency range. But with larger heat pumps, you can also earn more. Cheap designs can also be found on eBay Kleinanzeigen. I think no one will want to afford a design from the TGA office here for over 1000 euros. Installers currently do not perform room-by-room design. Why should they? It is ERR prescribed, so they can save themselves the effort.

Plumbers currently do not carry out room-by-room design. Why should they? ERR is mandatory, so they can save themselves the effort.

Then we are back to the questions I asked in the second post.
Where can I find plumbers who do and can do what makes sense and not just what is actually mandatory?
That will probably not be easy.
But it is mostly recommended that way in the three large German forums dealing with house construction, etc. Only nowhere does it say where to find someone who can do it the way it is recommended. There are experts who can do it themselves, but those will be very few. Especially through the forums, the number of people who even know about it and would like to implement it that way is increasing. Now you just have to know who can implement something like that for you.

That's how I feel now. After all I've read about the topic, I really want it to be done properly. And everywhere it says that the heat pump is not as easy as a gas boiler. So I would also like to award the contract to someone who really understands what they are doing and can provide references specifically in the topic: heat pump with room-specific heating load calculation and low supply temperature.

Best regards
Specki

Then all you have left is to pick up the phone and call everyone who has heating in their name and ask? Alternatively: Have the layout done on the internet and present it to the heating engineer to have it executed. It may not be met with enthusiasm, but the likelihood of ultimately getting a coherent overall concept is higher.

Sure, I'll ask all the regional ones here. At least the ones that appeal to me. But from everything you read in the forums, it would be almost like hitting the jackpot if one of them knows that and actually does it like that. I still have time. For now, just keep your eyes and ears open.

I honestly find it a bit overdramatic. Simply specify a maximum installation spacing of 10 cm everywhere, 5 cm in the bathroom, and install everything that can be installed. If you want 24 degrees in the bathroom, lay another wall or add an electric heater.

Before you find an installer who "cooperates," it's better to just design what is feasible. I don't find that elegant, though; in some rooms you probably end up with a very large overlap and have to throttle significantly. I can understand the concerns; it was and still is the same for me. The selection is not that large due to the workload. If you come from the start with expectations that are uncomfortable for the installer, you might only get defensive offers. Finding one who has flexibility is already something valuable. Calculate the heating load room by room yourself with Excel and the [EnEV] data and design the underfloor heating yourself. It takes some time, but you don't have to be an engineer to manage that.