Hello everyone!
I have been reading and researching online and in this forum for a long time now, but unfortunately, I’m still not much wiser when it comes to mechanical ventilation with heat recovery.
My partner and I are planning a single-family house (160 m² (1,722 ft²)) with gas and solar energy, built to the KfW-70 standard. Now we are wondering whether we should install a ventilation system.
Friends of ours have a decentralized ventilation system in their new build and are very happy with it—they can’t imagine living without it anymore.
However, in various forums, people often say that for new builds, a centralized system is better. The whole ducting, with maintenance and the potential for germs, gives me a weird feeling... I would constantly wonder what’s actually in the air inside my home. Is that a misguided concern?
And is the decentralized ventilation really that much worse than the centralized system? You hear that a lot.
What kind of costs should we roughly expect for a ventilation system? Is it true that centralized and decentralized systems cost about the same?
Thank you very much for all your advice!
Goldbeere
I have been reading and researching online and in this forum for a long time now, but unfortunately, I’m still not much wiser when it comes to mechanical ventilation with heat recovery.
My partner and I are planning a single-family house (160 m² (1,722 ft²)) with gas and solar energy, built to the KfW-70 standard. Now we are wondering whether we should install a ventilation system.
Friends of ours have a decentralized ventilation system in their new build and are very happy with it—they can’t imagine living without it anymore.
However, in various forums, people often say that for new builds, a centralized system is better. The whole ducting, with maintenance and the potential for germs, gives me a weird feeling... I would constantly wonder what’s actually in the air inside my home. Is that a misguided concern?
And is the decentralized ventilation really that much worse than the centralized system? You hear that a lot.
What kind of costs should we roughly expect for a ventilation system? Is it true that centralized and decentralized systems cost about the same?
Thank you very much for all your advice!
Goldbeere
Hello Perlenmann,
It’s great that you’re looking forward to your new system. Of course, I hope everything works to your satisfaction.
I don’t claim that such a system is useless. I just want to point out that some people find a ventilation system uncomfortable.
For example, my physiotherapist regularly tells me that he constantly feels a slight draft and therefore only runs the system on the lowest setting.
I myself am also extremely sensitive to drafts. For me, it’s very unpleasant.
By the way, I can’t tolerate air conditioning in cars either. After running it for half an hour in summer, I usually end up with a serious sinus infection.
But the last discussion was ultimately about whether a building with external thermal insulation composite systems (ETICS) is more prone to mold than a building without ETICS.
I’m of the opinion that, with improper ventilation, this can definitely be the case (although I don’t see a difference compared to a similarly well-insulated house without ETICS), but on the other hand, mold growth can sometimes be prevented because a warmer exterior wall removes the conditions mold needs.
With wall insulation combined with new windows, the windows are still likely to be the coldest spot. If moisture condenses anywhere due to a lack of ventilation, it will probably be there.
However, there are so many different opinions and theories on this topic that it ultimately leaves one feeling very uncertain.
Best regards
It’s great that you’re looking forward to your new system. Of course, I hope everything works to your satisfaction.
I don’t claim that such a system is useless. I just want to point out that some people find a ventilation system uncomfortable.
For example, my physiotherapist regularly tells me that he constantly feels a slight draft and therefore only runs the system on the lowest setting.
I myself am also extremely sensitive to drafts. For me, it’s very unpleasant.
By the way, I can’t tolerate air conditioning in cars either. After running it for half an hour in summer, I usually end up with a serious sinus infection.
But the last discussion was ultimately about whether a building with external thermal insulation composite systems (ETICS) is more prone to mold than a building without ETICS.
I’m of the opinion that, with improper ventilation, this can definitely be the case (although I don’t see a difference compared to a similarly well-insulated house without ETICS), but on the other hand, mold growth can sometimes be prevented because a warmer exterior wall removes the conditions mold needs.
With wall insulation combined with new windows, the windows are still likely to be the coldest spot. If moisture condenses anywhere due to a lack of ventilation, it will probably be there.
However, there are so many different opinions and theories on this topic that it ultimately leaves one feeling very uncertain.
Best regards
Hello,
we have now decided to build a house. Somehow, the idea of being less dependent on the oil industry was important to us, so we are currently researching a wide range of topics. My husband has become particularly focused on mechanical ventilation with heat recovery. In summer, an acquaintance gave me a talk about this and explained something about overpressure generation and headaches. My husband has now found out that decentralized ventilation causes this.
Could this be the answer to that question?
However, my logic tells me that both systems should somehow create some form of underpressure. Am I making a logical mistake here?
Best regards
we have now decided to build a house. Somehow, the idea of being less dependent on the oil industry was important to us, so we are currently researching a wide range of topics. My husband has become particularly focused on mechanical ventilation with heat recovery. In summer, an acquaintance gave me a talk about this and explained something about overpressure generation and headaches. My husband has now found out that decentralized ventilation causes this.
Goldbeere schrieb:
And is decentralized ventilation really that much worse than central ventilation?
Could this be the answer to that question?
However, my logic tells me that both systems should somehow create some form of underpressure. Am I making a logical mistake here?
Best regards
Hello,
Decentralized ventilation is typically used only for individual rooms.
Best regards
betschw schrieb:It is possible to become completely independent of that.
...we have now decided to build a house. Somehow the idea of not being so dependent on the oil industry was important to us, ...
betschw schrieb:What kind of training does this friend have? He certainly does not seem to be an expert on the subject!
... In summer, a friend gave me a presentation on this and explained something about overpressure generation and headaches.
betschw schrieb:No!
... Would that be the answer to this question?
betschw schrieb:Yes. The most advantageous solution is the one shown last in the picture. This achieves the most effective ventilation. The middle option is a cost-driven alternative often chosen. For a single-family house, it is still quite acceptable and justifiable. Both can be designed as overpressure, balanced pressure, or underpressure systems, the latter in the case of exhaust airflow surplus. The pressures involved are only a few pascals and are practically imperceptible to the human body. Anyone claiming otherwise is telling stories! For good reasons, although different ones, it is advisable to choose a balanced pressure system. A knowledgeable consultant managing the building project and also responsible for planning the building services (heating, domestic hot water, ventilation) should be able to provide sufficient information here. Without such a consultant, there is a risk of falling for pure sales claims.
... Do I have a logical flaw here?
Decentralized ventilation is typically used only for individual rooms.
Best regards
Thank you very much!
No, he was not a professional. Neither am I. It was basically just a cascade of words about what he had recorded himself from his building planner, which I then recalled and repeated in a probably inaccurate way over time.
At least now we are entering discussions with construction companies more informed, at least regarding this ventilation system.
I am now educating myself further about passive houses in general...
No, he was not a professional. Neither am I. It was basically just a cascade of words about what he had recorded himself from his building planner, which I then recalled and repeated in a probably inaccurate way over time.
At least now we are entering discussions with construction companies more informed, at least regarding this ventilation system.
I am now educating myself further about passive houses in general...
Häuslebauer40 schrieb:
Germany’s situation is quite absurd. On one hand, the energy-saving regulations aim to reduce energy consumption as much as possible, but on the other hand, people end up living in airtight buildings and then just lose energy through ventilation.
We decided against a mechanical ventilation system with heat recovery and instead installed four windows with ventilation features. I’m curious to see how that works out. Hi,
which ones do you have and how is it working for you? What’s your opinion on it?
Can you also share some information about the costs?
Regards
MaHaus
Bauexperte schrieb:
Hello,
This is rather rare...
To prevent condensation of water vapor in multi-layered building components, the thermal resistance should increase from the inside to the outside (thermal insulation layer on the outside) and the vapor diffusion resistance should decrease correspondingly. These conditions are met, for example, in wall constructions with: interior plaster, sand-lime solid bricks, mineral wool insulation, an air layer, and exterior cladding panels (wall with a ventilated facade). If the wall remains damp—something that must be considered especially in new buildings—water trapped behind a waterproof or water-repellent outer layer, such as a thermal membrane, has difficulty escaping through diffusion, which can cause long-term damage to the masonry.[1]
[Source 1] Kur, Friedrich; Wohngifte, Handbook for Healthy Building and Interiors...snip...Hi,
how is this handled with interior insulation?
We have a half-timbered house that is going to be insulated from the inside.
Thanks for any information and advice.
Regards,
MaHaus
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