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!
D
DerBjoern23 Oct 2013 13:26If you manage to do a short ventilation several times a day, about 3-5 times spread throughout the day, it should work even without a mechanical ventilation system.
R
Rowley65123 Oct 2013 14:10I thought I’d set up a few hygrometers to monitor the humidity levels, and then everything would be fine...
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perlenmann23 Oct 2013 14:45Rowley651 schrieb:
of the opinion that disciplined "shock ventilation" can also get the moisture out of the house. That certainly works. In cars, windows used to clear up from fog without air conditioning as well!
Ultimately, you have to ask yourself whether you want to and are able to do this?!
PS: Do you have a car without air conditioning?
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Rowley65123 Oct 2013 16:00Well, in a car, the air conditioning is mainly used for cooling rather than removing humidity. But to answer your question, yes, my car does have air conditioning...
Basically, we are always referring to the period from November to February/March when the mechanical ventilation with heat recovery plays a crucial role. During the rest of the year, we usually keep our windows tilted open, so fresh air naturally comes in and moisture can escape...
Does anyone have any experience WITHOUT mechanical ventilation with heat recovery and a KfW 70 house built with hollow brick walls without external insulation? Thanks in advance for your responses.
I can’t imagine the whole house would develop mold without mechanical ventilation with heat recovery, but there are some wild stories circulating online...
Basically, we are always referring to the period from November to February/March when the mechanical ventilation with heat recovery plays a crucial role. During the rest of the year, we usually keep our windows tilted open, so fresh air naturally comes in and moisture can escape...
Does anyone have any experience WITHOUT mechanical ventilation with heat recovery and a KfW 70 house built with hollow brick walls without external insulation? Thanks in advance for your responses.
I can’t imagine the whole house would develop mold without mechanical ventilation with heat recovery, but there are some wild stories circulating online...
P
perlenmann23 Oct 2013 16:43And the side effect of cooling is? Exactly, dehumidifying!
But then I ask again, why do you have air conditioning in your car? For comfort? You can have that same comfort in your home! Ventilating after a shower? Doesn’t matter. Fogged-up windows in the morning? No way.
But if you want to ventilate, go ahead! Whether your house will start to mold then depends on many factors.
I would say rather October to April. Since I don’t have to (cold) ventilate either, I also don’t need heating for a longer time!
You sound like you’re just looking for reasons to skip a mechanical ventilation system. But I’m not going to give you those arguments.
But then I ask again, why do you have air conditioning in your car? For comfort? You can have that same comfort in your home! Ventilating after a shower? Doesn’t matter. Fogged-up windows in the morning? No way.
But if you want to ventilate, go ahead! Whether your house will start to mold then depends on many factors.
I would say rather October to April. Since I don’t have to (cold) ventilate either, I also don’t need heating for a longer time!
You sound like you’re just looking for reasons to skip a mechanical ventilation system. But I’m not going to give you those arguments.
Perlenmann schrieb:
I would rather say October to April. But since I don’t have to (cold) ventilate, I also don’t need heating for a bit longer!The question is how long I can compensate for these ventilation heat losses through heating until the investment in a ventilation system pays off. It has already been mentioned several times in the forum that this investment in a ventilation system will probably never be profitable in euros, as long as I compensate by manual ventilation. If the house develops mold and requires expensive renovation, then the investment will of course pay off quickly. Otherwise, it is purely a comfort improvement.
We will also not install a mechanical ventilation with heat recovery in our house.
Better to have a house without mechanical ventilation than no house at all.
However, we will probably have to adjust quite a bit to ventilate that often. In our current apartment, the heat is lost even without ventilation, and depending on the weather conditions, ventilation can bring in more moisture than it removes.
So, ventilation happens very rarely.
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