Hello everyone,
We are currently starting to deal with the technical aspects of our single-family home.
I haven’t found a thread discussing whether a ventilation system generally makes sense or not. So here is a general discussion thread on the topic:
At first, we looked into various timber frame construction providers, which made us quite sensitive in this area. Naturally, a ventilation system is quite important due to the tighter building envelope, which I can completely understand. However, everything is also marketed accordingly...
Since we have now decided to go with a regional solid construction company, completely different questions arise:
I currently have a detailed offer from a solid construction company:
- $10,000 additional cost for thermal insulation measures
- $13,000 additional cost for a central ventilation system or $9,000 additional cost for a decentralized ventilation system
--> So the repayment subsidy of $18,000 is of little use to me; on the contrary, I am even paying extra for this (of course, I get a “better” house in return).
Key Data:
- Single-family home city villa, 150m² (1,615 ft²) with basement
- Air-to-water heat pump
- Building material: brick
The questions I am now asking myself:
1. Is a ventilation system even necessary to achieve KfW 55 standard?
2. If yes, would it maybe make more sense to go for KfW 70 and forget about the subsidy?
3. Is a ventilation system really that great? There are many reports about noise, high maintenance, etc.
4. If yes, in our building project would a decentralized or central system be better? I have read a lot of positive things about decentralized systems, so central ones might not be an option? Is that correct or not?
5. Is it even possible to reach KfW 55 standard otherwise? Do you really have to ventilate every 2 hours? Are there any experiences?
6. Is the additional $10,000 cost for KfW 55 without a ventilation system justified? Are the prices for the ventilation systems justified?
I know this is an endless debate and there are clearly two opinions here. However, we find it really difficult to make a decision. Maybe a few discussions and information here will help us make up our minds.
We are currently starting to deal with the technical aspects of our single-family home.
I haven’t found a thread discussing whether a ventilation system generally makes sense or not. So here is a general discussion thread on the topic:
At first, we looked into various timber frame construction providers, which made us quite sensitive in this area. Naturally, a ventilation system is quite important due to the tighter building envelope, which I can completely understand. However, everything is also marketed accordingly...
Since we have now decided to go with a regional solid construction company, completely different questions arise:
I currently have a detailed offer from a solid construction company:
- $10,000 additional cost for thermal insulation measures
- $13,000 additional cost for a central ventilation system or $9,000 additional cost for a decentralized ventilation system
--> So the repayment subsidy of $18,000 is of little use to me; on the contrary, I am even paying extra for this (of course, I get a “better” house in return).
Key Data:
- Single-family home city villa, 150m² (1,615 ft²) with basement
- Air-to-water heat pump
- Building material: brick
The questions I am now asking myself:
1. Is a ventilation system even necessary to achieve KfW 55 standard?
2. If yes, would it maybe make more sense to go for KfW 70 and forget about the subsidy?
3. Is a ventilation system really that great? There are many reports about noise, high maintenance, etc.
4. If yes, in our building project would a decentralized or central system be better? I have read a lot of positive things about decentralized systems, so central ones might not be an option? Is that correct or not?
5. Is it even possible to reach KfW 55 standard otherwise? Do you really have to ventilate every 2 hours? Are there any experiences?
6. Is the additional $10,000 cost for KfW 55 without a ventilation system justified? Are the prices for the ventilation systems justified?
I know this is an endless debate and there are clearly two opinions here. However, we find it really difficult to make a decision. Maybe a few discussions and information here will help us make up our minds.
exto1791 schrieb:
I recently had two new discussions with two different general contractors (GCs) — so three separate talks with GCs in total. The GCs nearby build almost everything in the surrounding new development areas and all have very good reputations.
All of them, really all, told me that KfW 55+ without mechanical ventilation is not a problem. You just need to ventilate normally, and that’s sufficient. They also all mentioned that the building material matters, and if bricks are used, due to their vapor permeability, there are no issues. Moisture release is therefore not a problem, and none of them have ever had mold problems so far. They said KfW 70 is quite similar to KfW 55. In principle, they would also build to KfW 70 standards, but given the subsidies, it doesn’t make much sense.
If there is a ventilation system, they all agree it should be installed as a decentralized system. For central ventilation, they all mentioned the same problem: the ducts get very dirty, and nobody really wants to look inside. What might accumulate over a few years is still not entirely clear. A few decades ago, people also said you can wash clothes by hand...
Yes, you can...
You can also write texts on a typewriter—even publish a book that way! Yes, you can, but you don’t have to (anymore)...
How many more pages will this take here... yes, a controlled mechanical ventilation system is great, super comfortable...
But you don’t need it to survive.
Do you drive a car? Manual transmission?
What about noise levels with a central ventilation system?
We’ve had extensive advice from an HVAC specialist, and our opinion was confirmed, so we are quite certain we want to go with a central ventilation system.
However, my partner is very sensitive to noise, so my question is: Can it actually be disturbing when falling asleep? Can you even hear it? Nowadays, with the installation of silencers and so on, this shouldn’t be a problem, right, or am I mistaken?
Another specialist said, “Well, some people are even bothered by the noise of the refrigerator”—to which my partner replied, “Yes, me too!”
If it really isn’t possible to have no disturbing noise at all, is it possible to leave out the ventilation in the bedroom, so that it could be ventilated manually instead?
We’ve had extensive advice from an HVAC specialist, and our opinion was confirmed, so we are quite certain we want to go with a central ventilation system.
However, my partner is very sensitive to noise, so my question is: Can it actually be disturbing when falling asleep? Can you even hear it? Nowadays, with the installation of silencers and so on, this shouldn’t be a problem, right, or am I mistaken?
Another specialist said, “Well, some people are even bothered by the noise of the refrigerator”—to which my partner replied, “Yes, me too!”
If it really isn’t possible to have no disturbing noise at all, is it possible to leave out the ventilation in the bedroom, so that it could be ventilated manually instead?
Ventilating the bedroom and eliminating excessive humidity are actually the main reasons for installing a (central) mechanical ventilation system with heat recovery.
Of course, the system produces some noise. However, with proper planning of the installation location, this noise should remain confined to that area.
If everything is done correctly, even at the highest setting, hardly any noise can be noticed in the sleeping rooms.
Of course, the system produces some noise. However, with proper planning of the installation location, this noise should remain confined to that area.
If everything is done correctly, even at the highest setting, hardly any noise can be noticed in the sleeping rooms.
Unfortunately, this is not true in most cases.
At the highest setting, all systems are quite audible. Sleeping is then not possible. However, at the lowest setting, you normally hear nothing or almost nothing. And the lowest setting is more than enough for ventilation; you only need more during parties...
At the highest setting, all systems are quite audible. Sleeping is then not possible. However, at the lowest setting, you normally hear nothing or almost nothing. And the lowest setting is more than enough for ventilation; you only need more during parties...
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