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.
Then the heating specialist should have had the heating load calculated before making his offer and wouldn’t have suggested 15cm (6 inches) in the first place... If he skipped the calculation, I would expect him, in return, to choose the shorter distance without bothering me.
Alternatively, it’s possible to do it as we did: we helped a little bit, and if he shows you how to do it, you can do it in 3 minutes too...
Alternatively, it’s possible to do it as we did: we helped a little bit, and if he shows you how to do it, you can do it in 3 minutes too...
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Benutzer2002 May 2022 10:16Raiweired schrieb:
KfW55 with a general contractor, size approximately 120 sqm (1,292 sq ft) over 2 floors. The price includes underfloor heating with a pipe spacing of 15 cm (6 inches), and 10 cm (4 inches) in the bathroom. Then it is a standard plan without proper preliminary planning. Either a higher flow temperature or a system designed for fossil fuels is assumed (since you are getting a heat pump, the former applies).
You won’t achieve 30/26°C (86/79°F) temperatures with that setup, so it will be less efficient.
Raiweired schrieb:
What additional cost per square meter would you estimate if the pipe spacing is reduced from 15 cm to 10 cm? That means about 3 meters of pipe per sqm (10 feet per sq ft) more. For 120 sqm (1,292 sq ft), roughly 400 meters (1,312 feet) extra. A 500-meter (1,640-foot) roll costs between 400 and 500 euros. Installation will take 2-3 hours longer. The manifold will be larger, but the number of heating circuits will likely stay the same.
So the real additional cost in euros will probably be under 1,000.
However, you should also receive a proper heating system design including room-by-room heat load calculations (considering your desired temperature – which you probably have not specified yet).
BUT, you will have to pay the price your general contractor sets, and they will certainly calculate to their own advantage…
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Deliverer2 May 2022 10:50Sure, but even if it costs a bit more: do it! Underfloor heating is a component you don’t want to have to replace after 20 years...
Snowy36 schrieb:
Then the heating specialist should have had the heat load calculated before making his offer and not have proposed 15
cm (6 inches) at all….One does not exclude the other.
It is possible to have the heat load calculated and still design for 15 cm (6 inches). In that case, for example, using a 35°C (95°F) flow temperature instead of 30°C (86°F) and 10 cm (4 inches) spacing 😉
Snowy36 schrieb:
Yes, if you want to be as inefficient as possible, always gladly ☺That probably is how it went 🙁
I just wanted to say that one does not exclude the other.
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