S
Sternchen318 Nov 2019 12:18Hello,
I will link the main topic of our purchase of a semi-detached shell construction later tonight so that the construction description and the submitted plans can also be viewed.
But for the current question, this is probably a better place.
Facts:
We are buying an already existing shell construction from the developer. The developer initially wanted to sell it as a complete turnkey package, but we found out by chance that the semi-detached house is still available, so we are stepping in now. This also means that we now have a say in everything else and can be involved in the planning. The shell with a fully basement is finished, the windows are installed, and the roof is also completed. The electrician started work yesterday. The house is being built as a KfW 55 energy-efficient house.
Question:
The developer planned a decentralized ventilation system, but according to them, it is not necessary to achieve KfW 55 certification and can still be canceled if we do not want it. The ventilation is done by individually installed, controlled room ventilation units with heat recovery.
We have read a lot about decentralized and centralized ventilation systems but are very uncertain. We ventilate at least twice daily and have never had problems in any rental apartments or houses so far. Therefore, we wonder if this system is really necessary. A centralized ventilation system would no longer be feasible at this stage of construction.
According to the developer, if we cancel it, the planned costs will be removed from our invoice, but we do not know for sure if they will fully deduct this because we do not know how much it accounts for in the overall calculation.
What are your thoughts on the decentralized ventilation system? Is it really useful, necessary, etc.?
I will link the main topic of our purchase of a semi-detached shell construction later tonight so that the construction description and the submitted plans can also be viewed.
But for the current question, this is probably a better place.
Facts:
We are buying an already existing shell construction from the developer. The developer initially wanted to sell it as a complete turnkey package, but we found out by chance that the semi-detached house is still available, so we are stepping in now. This also means that we now have a say in everything else and can be involved in the planning. The shell with a fully basement is finished, the windows are installed, and the roof is also completed. The electrician started work yesterday. The house is being built as a KfW 55 energy-efficient house.
Question:
The developer planned a decentralized ventilation system, but according to them, it is not necessary to achieve KfW 55 certification and can still be canceled if we do not want it. The ventilation is done by individually installed, controlled room ventilation units with heat recovery.
We have read a lot about decentralized and centralized ventilation systems but are very uncertain. We ventilate at least twice daily and have never had problems in any rental apartments or houses so far. Therefore, we wonder if this system is really necessary. A centralized ventilation system would no longer be feasible at this stage of construction.
According to the developer, if we cancel it, the planned costs will be removed from our invoice, but we do not know for sure if they will fully deduct this because we do not know how much it accounts for in the overall calculation.
What are your thoughts on the decentralized ventilation system? Is it really useful, necessary, etc.?
Opinions vary widely on this topic. You will receive several different answers, and everyone will say something different.
I would not want to live in a KfW 55 house without a mechanical ventilation system, whether decentralized or centralized. Nowadays, you often just get a plastic bag placed in the building (due to current regulations). It doesn’t breathe, but gases quietly accumulate for the first few years. It’s similar to a new car.
Rental apartments and newly built houses are two completely different matters. The ventilation behavior and especially the air exchange volumes in a single-family house or a semi-detached house are significantly larger. This means you have to ventilate more often and thoroughly—and it should be done by airing the rooms briefly and intensely, not by leaving the windows tilted open.
If you have the time to walk through the house several times a day and do this, you can have the mechanical systems removed. I wouldn’t do it.
I would not want to live in a KfW 55 house without a mechanical ventilation system, whether decentralized or centralized. Nowadays, you often just get a plastic bag placed in the building (due to current regulations). It doesn’t breathe, but gases quietly accumulate for the first few years. It’s similar to a new car.
Rental apartments and newly built houses are two completely different matters. The ventilation behavior and especially the air exchange volumes in a single-family house or a semi-detached house are significantly larger. This means you have to ventilate more often and thoroughly—and it should be done by airing the rooms briefly and intensely, not by leaving the windows tilted open.
If you have the time to walk through the house several times a day and do this, you can have the mechanical systems removed. I wouldn’t do it.
S
Sternchen318 Nov 2019 12:36Mycraft schrieb:
Opinions vary on this. You’ll get several different answers, each offering a different perspective.
Personally, I wouldn’t want to live in a KfW 55 house without a mechanical ventilation system, whether decentralized or centralized.
Rental apartments and newly built houses are completely different matters. Ventilation habits, especially the volume of air exchanged, are significantly greater in a single-family home or a semi-detached house. This means you need to ventilate more frequently and thoroughly—using shock ventilation rather than leaving windows tilted.
If you have the time to go through the house several times a day to do this, then you might consider doing without these systems. I wouldn’t recommend it.Hello, thanks for the reply. We have also lived in a newly built apartment of 110 sqm (1,184 sq ft) as first occupants and didn’t have any problems there. But yes, a semi-detached house with multiple floors is naturally quite a different matter. We ventilate 2-3 times a day using shock ventilation, even now in our current rental home—usually about 10 minutes each time, then close everything up again.
Is this extra important mainly because of the drying phase in new construction, which takes significantly longer than the building process itself, or is it generally important to ventilate regularly with shock ventilation? Does it have something specifically to do with the KfW 55 house standard, meaning that ventilation habits need to be more intensive?
You can completely forget about decentral ventilation systems—definitely remove them. They are too disruptive in every way: noise, external sounds, drafts, dirt accumulation, and they don’t look good. Almost all of our acquaintances have turned theirs off. I also had a decentral system once and was very dissatisfied.
Now, with the Zehnder central ventilation system, it’s a dream—I don’t want to live without it. Unfortunately, I guess that option is no longer available for you?
In that case, just install a humidity-controlled exhaust fan in the bathroom and nothing else is really needed.
You probably prefer to ventilate manually anyway.
Now, with the Zehnder central ventilation system, it’s a dream—I don’t want to live without it. Unfortunately, I guess that option is no longer available for you?
In that case, just install a humidity-controlled exhaust fan in the bathroom and nothing else is really needed.
You probably prefer to ventilate manually anyway.
An excerpt from an article on ventilation intervals:
In addition to moisture removal, airtight construction introduces damage aspects previously unknown to building professionals: emissions from furniture and building materials. Pollutant release usually occurs continuously, so short ventilation intervals or constant background ventilation are necessary to limit concentration levels. As an example of the pollutant issue, emissions from typical carpet flooring can be mentioned: according to a study by the University of Essen, one square meter of newly installed carpet emits enough pollutants to require an air exchange rate of 1.0–4.0/h to maintain hygienic indoor air quality. In practice, however, newly constructed or renovated buildings only achieve air exchange rates of 0.1–0.15/h. This deficiency in background ventilation especially leads to high pollutant concentrations and odor nuisances during periods when the space is unoccupied.
Also of particular importance is limiting the CO2 concentration. Without air exchange, the level rises quickly to hygienically unacceptable values. This can cause fatigue, reduced concentration, headaches, and other nonspecific symptoms for inhabitants.
In addition to moisture removal, airtight construction introduces damage aspects previously unknown to building professionals: emissions from furniture and building materials. Pollutant release usually occurs continuously, so short ventilation intervals or constant background ventilation are necessary to limit concentration levels. As an example of the pollutant issue, emissions from typical carpet flooring can be mentioned: according to a study by the University of Essen, one square meter of newly installed carpet emits enough pollutants to require an air exchange rate of 1.0–4.0/h to maintain hygienic indoor air quality. In practice, however, newly constructed or renovated buildings only achieve air exchange rates of 0.1–0.15/h. This deficiency in background ventilation especially leads to high pollutant concentrations and odor nuisances during periods when the space is unoccupied.
Also of particular importance is limiting the CO2 concentration. Without air exchange, the level rises quickly to hygienically unacceptable values. This can cause fatigue, reduced concentration, headaches, and other nonspecific symptoms for inhabitants.
Hello everyone,
The ducts for a central controlled residential ventilation system can also be installed as flat ducts on the raw concrete ceiling within the floor insulation, if the floor construction allows it.
This might still be possible during your shell construction phase.
Almost all reputable manufacturers offer a solution for this (in the concrete ceiling, on the concrete ceiling, or within boxed enclosures).
The ducts for a central controlled residential ventilation system can also be installed as flat ducts on the raw concrete ceiling within the floor insulation, if the floor construction allows it.
This might still be possible during your shell construction phase.
Almost all reputable manufacturers offer a solution for this (in the concrete ceiling, on the concrete ceiling, or within boxed enclosures).
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