Hello everyone,
maybe someone here can give us a good tip, as we are quite uncertain about a ventilation system.
We are planning to build a house (solid construction) according to KfW 70 standards, with underfloor heating, a fireplace, and a solar system. That much is already decided.
We received an offer from Company A for a ventilation system with heat recovery, and the salesperson recommended it to us.
At Company B, the ventilation system is significantly more expensive, and the salesperson told us that since the house is so well insulated, moisture would not be an issue... where would it come from? The rest could be regulated by normal airing anyway.
(I also think he realized that his ventilation system would have blown our budget and now I worry that he advised us against it just for that reason!)
My husband and I are laypersons, but my instinct tells me that the better the house is insulated, the more problems I would have getting rid of moisture and stale air inside the house, right?
After all, a blower door test does show that there is very little air circulation.
Am I completely wrong?
We are a bit torn now, since such a system is not exactly cheap! But is it necessary, or just a nice extra?
Thank you very much for your help!
maybe someone here can give us a good tip, as we are quite uncertain about a ventilation system.
We are planning to build a house (solid construction) according to KfW 70 standards, with underfloor heating, a fireplace, and a solar system. That much is already decided.
We received an offer from Company A for a ventilation system with heat recovery, and the salesperson recommended it to us.
At Company B, the ventilation system is significantly more expensive, and the salesperson told us that since the house is so well insulated, moisture would not be an issue... where would it come from? The rest could be regulated by normal airing anyway.
(I also think he realized that his ventilation system would have blown our budget and now I worry that he advised us against it just for that reason!)
My husband and I are laypersons, but my instinct tells me that the better the house is insulated, the more problems I would have getting rid of moisture and stale air inside the house, right?
After all, a blower door test does show that there is very little air circulation.
Am I completely wrong?
We are a bit torn now, since such a system is not exactly cheap! But is it necessary, or just a nice extra?
Thank you very much for your help!
Soroka schrieb:
Exactly...(I also meant the part about the two pairs of shoes) But a comment from someone in the thread titled “see headline” who doesn’t even have a KfW 70 house but claims it works without much ventilation is quite odd. Without proper airtightness, KfW 70 is not truly KfW 70. Ventilation is not about how well insulated a building is, but how airtight it is. Ask some experts who conduct blower door tests about building damages caused by air leaks (for example, constant condensation in places where moisture shouldn’t be).
As an example, my current older apartment: I don’t ventilate at all (only occasionally ventilate the bathroom, but not even there after showering in winter—brr). Still, there is no mold anywhere.
Of course, it is possible to manage without mechanical ventilation, but some form of ventilation is required for certain types of buildings, even if it’s just window trickle ventilation.
Also, controlled mechanical ventilation is not intended for drying out buildings.
B
BauProjekt1412 May 2014 19:17Of course, a ventilation system is not mandatory... However, if you have a truly airtight house, you cannot expect that humidity will be effectively managed by ventilating just once a day.
Soroka schrieb:
Unlike you, I addressed the title. Everything else might be nice to have, but it’s not mandatory.
You seem to have significant financial interests in this topic… if you read your posts…
But I’ll step out again now, carry on firing away… Very interesting, but I work in a completely different field and wouldn’t know how to profit from a ventilation system in any way.
By the way, we only responded to your somewhat aggressively worded posts (“headline”). Just take a look at the KfW Bank website and read the documents for KfW 70. You will see that airtightness is an essential part of such a building, and only with the appropriate proofs can a house be classified as “KfW 70” standard. Without proof—no KfW 70. Apparently, you don’t know (no proof!) if your building is airtight enough. So your statement here in the thread that you don’t need a ventilation system because airing the space once is sufficient is misleading, since there is no KfW 70 certification. This is not criticism of you or your building (it’s good that everything is fine with you!), but the point is that this statement could put others in a disadvantageous situation.
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