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
DerBjoern21 Mar 2014 07:45Congratulations, Lacos! You have fallen for a purely panic-inducing post!
Modern controlled residential ventilation systems use filters. Nothing gets dirty anymore...
The TV report you linked is complete nonsense...
@fragri
With my controlled residential ventilation system, the smell of manure stays outside.
That doesn’t work with window ventilation.
Modern controlled residential ventilation systems use filters. Nothing gets dirty anymore...
The TV report you linked is complete nonsense...
@fragri
With my controlled residential ventilation system, the smell of manure stays outside.
That doesn’t work with window ventilation.
D
DerBjoern21 Mar 2014 08:34However, filter bags can also be installed in the exhaust air diffuser valves.
We are currently building a KfW 70 house, using brick construction, vapor-permeable, and completely without a mechanical ventilation system. For us, the disadvantages of such a system are simply too significant. At first, I thought I wouldn’t build without one because I have allergies, but after some inquiries, research, and trials, we quickly moved away from the idea.
The biggest disadvantages from our perspective are:
- The very low indoor humidity, sometimes below 25% in winter, is extremely unhealthy and can lead to respiratory illnesses. People’s countermeasures include hanging wet carpets, placing humidifiers in rooms, or turning off the system altogether—which then calls into question the purpose of having the system at all.
- The system must always be running; otherwise, there is a risk of water deposits forming, which can breed bacteria and cause contamination throughout the rooms.
- The ongoing maintenance costs.
- Constant dust exposure due to continuous air movement. Studies show that indoor fine dust levels can sometimes exceed those found on busy city streets.
- Possible odor buildup in the ducts over time, which is then distributed throughout the rooms, as well as potential noise disturbances from the system—for example, in bedrooms. Many people are bothered by the humming or buzzing sound, which, although usually below the threshold for noise disturbance in bedrooms (around 30 dB), is still audible—and it would bother me.
At the moment, I see it mostly as a marketing gimmick to extract money from people and a way to meet required energy standards. My opinion: In a normally constructed new house, mold does not develop; it would take quite extreme conditions, especially considering the surface temperatures, which makes mold formation almost impossible.
Almost all construction companies told us that such a system is essential and that building without one is no longer possible nowadays. When we asked about disadvantages, the only answer we got was “there are no drawbacks.” That’s why we questioned the use of these systems. It is really difficult to get independent advice.
From an energy perspective, it is a zero-sum game; climatically and biologically, it is a disaster (we like knowing whether it is snowing outside or summer!).
The biggest disadvantages from our perspective are:
- The very low indoor humidity, sometimes below 25% in winter, is extremely unhealthy and can lead to respiratory illnesses. People’s countermeasures include hanging wet carpets, placing humidifiers in rooms, or turning off the system altogether—which then calls into question the purpose of having the system at all.
- The system must always be running; otherwise, there is a risk of water deposits forming, which can breed bacteria and cause contamination throughout the rooms.
- The ongoing maintenance costs.
- Constant dust exposure due to continuous air movement. Studies show that indoor fine dust levels can sometimes exceed those found on busy city streets.
- Possible odor buildup in the ducts over time, which is then distributed throughout the rooms, as well as potential noise disturbances from the system—for example, in bedrooms. Many people are bothered by the humming or buzzing sound, which, although usually below the threshold for noise disturbance in bedrooms (around 30 dB), is still audible—and it would bother me.
At the moment, I see it mostly as a marketing gimmick to extract money from people and a way to meet required energy standards. My opinion: In a normally constructed new house, mold does not develop; it would take quite extreme conditions, especially considering the surface temperatures, which makes mold formation almost impossible.
Almost all construction companies told us that such a system is essential and that building without one is no longer possible nowadays. When we asked about disadvantages, the only answer we got was “there are no drawbacks.” That’s why we questioned the use of these systems. It is really difficult to get independent advice.
From an energy perspective, it is a zero-sum game; climatically and biologically, it is a disaster (we like knowing whether it is snowing outside or summer!).
B
Bauexperte27 Mar 2014 16:38Hello,
Best regards, Bauexperte
HighDef schrieb:This is also how my partner argues; he is not only a businessman but also a trained gas and heating technician.
The biggest disadvantages from our perspective:
- The very low indoor humidity, sometimes below 25% in winter, is extremely harmful to health and promotes respiratory illnesses. People try to counteract this by hanging wet carpets, placing humidifiers in rooms, or turning off the system entirely – which then raises questions about the system’s purpose...
- The system must always be running; otherwise, there is a risk of water deposits forming, which can lead to bacterial growth and contamination of the entire indoor space.
- Ongoing maintenance costs
- Constant dust exposure, since air is always moving. Studies show that indoor fine dust levels can sometimes be higher than on busy city streets...
- Possible odor buildup in the ducts after several years, spreading into all rooms, as well as potential noise disturbance from the system, for example in bedrooms (many people are bothered by the humming or buzzing sound, which is usually below the typical noise limit for bedrooms – believed to be around 30dB – but still audible, and personally, I would find it annoying)
Best regards, Bauexperte
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