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

Hello everyone,

do the heating engineers know that the underfloor heating is best sized/planned through a room-by-room heating load calculation?

The room-by-room heating load calculation is also important for the selection of the heat pump (with us either water-water or brine-water), or is the "general heating load calculation" of the entire house according to DIN 12831 sufficient there?

If my architect does not offer that, who should I turn to? What do I need to look for in the Yellow Pages / on the internet, someone who can professionally assist me?

Because from what I have read here in the last few months, a room-by-room heating load calculation is very important. With an accurate calculation, you can save money because the heat pump selected accordingly then runs more efficiently and you can heat your house more effectively.

Thank you very much for the answers,
Greetings from BaWü
Ann.

PS: Am I wrong, or can the general heating load calculation according to DIN 12831 really be independently checked/recalculated (if you have all the U-values of the building envelope, of course)? Are there already predefined templates on the internet for this? Maybe also for the room-by-room heating load calculation, or is that usually too complex for the builder?

I'm also currently working a bit on this topic ^^

So, if I understood correctly, you DO NOT initially need the room-by-room heating load calculation to choose the heat pump. It's sufficient to know the total heating load of your house. The heat pump has to heat the entire house and does not heat each room individually.

But for laying the underfloor heating, you do need the room-by-room heating load calculation again so that you know how many meters of heating pipe to lay per room.

And then, for setting up the heat pump, this is probably again advantageous.

It's best to forgo individual room control and keep the flow temperature as low as possible. A hydraulic and thermal balancing must then also take place.

So, I hope this is correct now, if not please correct me. I'm just starting to deal with the topic.

What I do wonder is how to find an installer who CAN do all this and also WANTS to do it.
That will probably be really difficult. Maybe there are hints about suitable installers in the HTD forum.
And how do I bypass the obligation for individual room control? Or is that probably not checked anyway? So it could be enough if I agree with the installer on it and don't make a big deal out of it anywhere?

Are there people here who have implemented it like this?

I'll be reading along with interest and hope I haven't said too many wrong things ^^

Best regards
Specki

What I do wonder though. How do I find an installer who CAN do all this and also WANTS TO DO IT.

That's exactly what's bothering me too. Sure, the heating engineer will probably take care of that when installing the underfloor heating, but - without wanting to disparage all heating engineers - usually rather quick and rough and "it'll do." But that you could make it really more efficient through an exact room-by-room calculation and save money that way is probably rather not important to him? So who do you bring on board if you want to do it as precisely as possible (= efficient and economical for the heating)?

No, just as you wrote it with the underfloor heating and pipe length, I have summarized it here the same way. And also the thing with the ERR I have read so often. If you want to do everything by the book, you can also be exempted from it (application to the authority). But it probably depends on the local official whether he accepts that or not (search on the internet for the thread "Planning underfloor heating - completely do without ERR?"). Or you really find a heating engineer who then deliberately overlooks that against regulations. Or you install everything with absolutely minimal effort and then disconnect the ERR again.

The most professional and thus also the most cost-effective way to perform a heat load calculation according to DIN 12831 is by an engineering office for TGA (Technical Building Equipment) or, somewhat more conventionally: for building services engineering. Occasionally, building energy consultants/energy consultants from the KfW-dena list are also professionally capable of doing this, but mostly at significantly higher costs. Heating/plumbing companies usually do not offer this service because it is too complicated. However, the architect accompanying the construction should be able to refer you to a suitable office for this service if they are managing your construction project.

You can calculate the heating load with MH software (free freeware), you just have to spend two or three evenings dealing with it.

It will never match 100% with that of your heating engineer, general contractor, or MEP planner. But even they will not calculate exactly the same result among themselves.

Nowadays, heating engineers apparently no longer do this during the offer phase. Instead, they get it provided as a service from their regular supplier for heat generators and underfloor heating. Accordingly, the calculation is then superficial (which may also be due to the available time).

Back when I was still working in the industry, the heating company still did the calculations themselves and apprentices learned how to calculate this in vocational school.

A heating engineer will be able to do that. I wouldn’t hire a specialist engineer (TGA) for that unless you have too much money. Just don’t expect it to be done free of charge during the offer phase. Have the calculation specifically offered and request the documentation for it.