TGA planner difficulties, underfloor heating supply temperature + wastewater ventilation

What kind of heat pump is being installed.

Of course, I also have incomplete information there. So far, I only know that a Vaillant Arotherm Split VWL 75/5 AS with uniTower VWL 78/5 IS has been ordered. Let's see what will be available when. I think the developer will certainly be finished by February/March, looking at the current progress. However, I do not yet see that the heat pump will already be there. It was probably only ordered 2-3 weeks ago.

I find the whole approach of the planners rude and unprofessional. But whatever, you are bound by it.

That’s how it is. They probably thought it was easy money. The project has a total of 15 residential units, run quickly through the software, and done. But many things in the planning were really bad. Many things could be managed, some unpleasant facts had to be accepted, but the executing trades at least give a good impression so far. I haven’t approached the sanitary workers yet; maybe they also hired good people there.

I have studied the standard again and am now quite certain that the lower outside temperature should be used. That would of course be a great point of argument against the technical building services planner. I also have to argue with the developer why I am causing so much trouble and questioning almost every decision of the TGA planner. This naturally leads to additional effort, which they would like to pass on to me. If I then say that the planning work was based on outdated standards, I should have a good argument that the additional planning should not be at my expense.

If the planner designs the hydraulics for -16, that's clearly better for you than -11. So it could be that you are actually causing yourself a deterioration with that.

I also don't see much advantage in continuing to discuss with the TGA. Either you do it yourself, have it done externally, or live with the average solution. ;)

The discussions will mostly be over by Monday. The planning is supposed to be discussed then. Doing it yourself or externally unfortunately no longer works. I have already come to terms with an average solution.

If the planner designs the hydraulics for -16, that is clearly better for you than -11.

Is that so? I would have thought that the planned supply temperature could be chosen somewhat lower and that the rooms might also be better proportioned to each other. I could also imagine that the long heating circuits might be somewhat reduced.

You mean it would be worse to calculate with -11° because, for example, the necessary laying distances could increase?

-11 or -16 should actually not make a big difference in the installation distances. So you now have no other choice and have to get through it.

Only the heat pump should definitely not be larger than 7kW, according to your heating load at -16°C. That would have been the lever to optimize to a 5kW heat pump.

The 7kw heat pump is currently planned. I do not assume that an optimization to 5kw is possible with the team. In the end, the planner also has to be responsible for achieving the temperatures, and he certainly will not want to take on that responsibility. I also think the house does not support that.

The appointment was basically good, although it somehow went absurdly. I had prepared several topics, and for every question, the planner got stuck, didn't really know how to answer, had to look up values that she could only explain with a lot of discussion, etc. It basically came down to always saying "The software calculated it this way, I don’t know where it comes from." In their place, I would have sunk into the ground out of shame, and I can now also well understand why they resisted handing out the planning. All of this does not help me tremendously yet but at least gives a good feeling, and since I was able to point out several errors, I also have good arguments that the developer cannot charge me for the additional planning effort. By the way, no answer could be found regarding which standard outside temperature must be used. I referred to the standard, and the planners said, "We only enter a postal code in the software, we cannot change the value then." Let's wait and see how this develops.

The most important point was actually that I noticed that the shower in the main bathroom was not used as a heating surface. So, we have a bathroom of 9.5m², of which 6.1m² were used as a heating surface (shower, bathtub subtracted). The shower is now also used as a heating surface, which always gives us about 1.6m² or 25% more heating surface. In the other rooms, parquet was calculated instead of vinyl, which shall now also be changed.

Other points were that she only calculated with 22° or 24° bathroom temperature ("23° is an odd number anyway") and that the installation spacing could only be adjusted in 5cm steps ("it doesn’t work otherwise with the nodule system"). Since I do not find the number 23, despite being a prime number, so bad and no nodule system is used but a staple system, there is further optimization potential here as well.

End of the story: Another new plan will be made, in which I now have a bit more hope that it will rather reach a 3+ instead of a 4- within the framework of an average planning. Let's see.

Yes, realistically speaking, you won’t be able to plan it "optimally." The right partner and your influence on it are missing. It’s not an individual contract. But considering the circumstances, you have already come miles further than many others in your situation. You can optimize, and the remaining 10% won’t make much of a difference anyway. I haven’t read through the entire thread again. What just occurs to me and might be influenceable... where are the HKV located? It would be elegant to sensibly place them in bathrooms because they give off heat. It helps in the bathroom because it’s already tight there. In the hallway or in a storage room or in the technical room, it’s basically useless, and no additional heat is needed or desired. If they are in the hallway, make sure the supply lines are insulated. Otherwise, you might have the effect that even if you turn off the heat in the hallway, it’s still warm because the supply lines are heating it, and the bathroom needs the temperature more than the hallway.