Good morning, I am currently building a single-family house to KfW55 standard with a general contractor, approximately 120 sqm (1,290 sq ft) over two floors. The price includes underfloor heating with a pipe spacing of 15 cm (6 inches), and 10 cm (4 inches) spacing in the bathroom. In many threads, a pipe spacing of 10 cm (4 inches) is recommended for all rooms. This requires about 3 m (10 feet) more piping per square meter. In your experience, what additional cost per square meter should I expect if the pipe spacing is reduced from 15 cm (6 inches) to 10 cm (4 inches)? I am waiting for the offer from the general contractor but would just like to know what the cost increase might be based on your experience. Once I have the offer, I will share the actual additional costs with you.
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RotorMotor2 May 2022 11:1315cm (6 inches) can definitely make sense. Switching generally from 15.10 to generally 10.7.5 does not necessarily work better.
Yes, for example, IB Heckmann also planned only 15cm (6 inches) in my open space. If there is already a lot of area, the supply air diffuser doesn’t always need to be very low. What is almost more important is that in small rooms like bathrooms or corner children’s rooms, the supply air diffuser might be even lower than 10cm (4 inches). For example, 7.5cm (3 inches), but yes, all of this needs to be calculated.
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Benutzer2002 May 2022 11:39RotorMotor schrieb:
15cm (6 inches) can definitely make sense. But not as a blanket rule for the entire house like the OP 😉 .
I would rather go with a flat 10cm (4 inches) and have too much insulation, which in the end wouldn't be a problem.
But yes, it
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Raiweired2 May 2022 14:05Many thanks for the assessments. I will have the general contractor show me the calculations for review by my neighbor (master heating engineer). The general contractor will surely need to request these calculations from the heating engineer. Is the heating engineer required to provide the calculations to the general contractor, and the general contractor in turn provide these documents to me, or is it simply goodwill if they do so?
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Benutzer2002 May 2022 15:35Raiweired schrieb:
The general contractor definitely needs to request these calculations from the heating engineer. Does the heating engineer have to provide the calculations to the general contractor, and the general contractor then give me these documents, or is it just goodwill if they do? It’s not mandatory. However, if I’m building a house worth half a million, I would definitely want to have the relevant documents for myself.
A heat load calculation and heating system design are basic documents in that case.
Whoever pays the piper calls the tune.