TGA planner difficulties, underfloor heating supply temperature + wastewater ventilation

10% will not make a big difference afterward.

Thank you! You are certainly right about that. I like to deal with such topics and want to get the optimum out of it. However, I am not the builder but the buyer, they are not my planners but those of the developer, so the 90% are simply the optimum. Regarding the HKV, that is a good approach, but no longer possible in our case. The positions are once in the dressing room and once in the hallway under the stairs. You don't need the heat there, you are absolutely right. Maybe it will help someone else if they come across the thread. Thanks for the tip. The expert (the appointment was also yesterday) also pointed out the insulation of the supply/return lines. Currently, there is aluminum-coated mineral wool (branch pipes and bends) and PE soft foam (in the screed).

Surprising that the market has not yet priced in such a performance.

But congratulations to you! Through perseverance, research, and immersing yourself in an unfamiliar subject, you have achieved the optimum for yourself given the circumstances. Not everyone can do that, not everyone wants to, and they must then bear the consequences in later operations.

Wow. Your persistence is admirable! It's really crazy what companies get away with. I think if less construction happens now, these "low performers" will slowly get into trouble. Then it won't be a case of a developer not caring how (un)satisfied the buyers are if there aren't immediately a hundred more lining up. The problem is still the lack of transparency due to specially founded project GmbHs. So the buyers don't always know which projects are actually realized by the same company in the end.

Thank you very much for your encouragement. You always feel a bit like a nitpicker, but overall it’s simply about too much money. Without forums like this, as a layperson you would be pretty much helpless. That’s really great. We are at least lucky that our developer is basically a two-man company. So you somehow get access to the people. That’s of course much more difficult with a large developer. I hope the builder is slowly realizing the kind of performance the TGA planner is delivering here. Nevertheless, it’s probably a good deal for him. There are a total of 15 residential units; he has a lot of trouble with me but makes a high margin with the rest.

You then quite certainly have the most efficient system in the construction project.

It's a pity that it's so complicated. Even a wall heating system like that is not rocket science. Just the partition wall between the shower and the toilet would be, depending on the height of the wall, 2 times 2-2.5 m² of heating surface...
They also wouldn't want to deduct an electric towel dryer, radiator, infrared heating in the mirror, etc. from the heating load.
The suboptimal planning mainly comes from the heating load of the bathrooms.

So, there is an update. The planner has now corrected the conditions again (primarily shower as heating surface, outdoor temperature according to standard, vinyl as floor covering) and comes to a supply temperature of 36°C with a bathroom temperature of 23°. These are all just calculated values, but it feels better than 40°C as originally planned. What is really absurd is that the -11.3°C outdoor temperature is correct. Regardless of what influence this has, this means for me that all calculations of the last 2.5 years were made with incorrect standard values. Really crazy this story.

Calculations now result in pipe spacing of 20 cm on the ground floor and 10-15 cm on the upper floor, which of course I don't like again. I have some differences between parquet and vinyl. According to her calculation, she needs either 3 heating circuits with 5 cm pipe spacing (38°C supply temperature/parquet) or 2 heating circuits with 10 cm pipe spacing (36°C supply temperature/vinyl) for a 15 sqm room. I find that really remarkable if her calculation is correct. On the ground floor we will therefore go with 15 cm pipe spacing, upstairs consistently with 10 cm. This also works very well with the heating circuit lengths. As I understand it, I then have to make sure in reality that the bathroom gets warm enough and if that is the case, I can lower the supply temperature further. Is that the correct way of thinking?

Of course, I have only seen excerpts again, but I assume that the heating circuit in the bathroom is now the only one that exceeds the length. I would ask about that again.

Calculations probably come to a heating load of roughly 6.3-6.4 kW now. The 7 kW heat pump would be too large for that, but a 5 kW would probably not be enough, right? Aside from that, it is now also ordered, so it will be difficult to change anything.

Good grief, I will be glad when this topic is over! ;)