Hello everyone,
we are building a KfW 70 house, which is economic even without a mechanical ventilation system.
Now, like many others, we are uncertain whether we really want to install a mechanical ventilation system. It has been planned, but the prices quoted are quite high... A decentralized system also seems to be similarly expensive due to the number of rooms and additionally causes quite a few holes in the nice facade...
Our heating engineer, who also installs ventilation systems, suggested installing fans in the exterior walls of the wet rooms (guest toilet and bathroom). These would be controlled by a switch and/or humidity sensors to extract the moist air from the rooms.
Additionally, a cooker hood with exhaust ventilation is recommended for the kitchen.
What do you think about this?
From a cost perspective, it does seem to be considerably cheaper.
we are building a KfW 70 house, which is economic even without a mechanical ventilation system.
Now, like many others, we are uncertain whether we really want to install a mechanical ventilation system. It has been planned, but the prices quoted are quite high... A decentralized system also seems to be similarly expensive due to the number of rooms and additionally causes quite a few holes in the nice facade...
Our heating engineer, who also installs ventilation systems, suggested installing fans in the exterior walls of the wet rooms (guest toilet and bathroom). These would be controlled by a switch and/or humidity sensors to extract the moist air from the rooms.
Additionally, a cooker hood with exhaust ventilation is recommended for the kitchen.
What do you think about this?
From a cost perspective, it does seem to be considerably cheaper.
N
nordanney3 Dec 2013 11:23fragri schrieb:
I believe a healthy indoor climate can also be achieved by choosing a wall structure that can absorb and release moisture.What should the wall structure look like then, and where is the wall supposed to release the moisture if the house is airtight?Hello,
for example, certain building materials can help regulate moisture, such as clay bricks or calcium silicate bricks. At least that’s how several professionals in my network have explained it to me.
If the house is completely sealed on the outside, for example by using external thermal insulation composite systems (ETICS), this effect is obviously not possible. However, if you use a vapor-permeable insulation (cavity insulation), the wall can "breathe" while still providing thermal insulation.
for example, certain building materials can help regulate moisture, such as clay bricks or calcium silicate bricks. At least that’s how several professionals in my network have explained it to me.
If the house is completely sealed on the outside, for example by using external thermal insulation composite systems (ETICS), this effect is obviously not possible. However, if you use a vapor-permeable insulation (cavity insulation), the wall can "breathe" while still providing thermal insulation.
D
DerBjoern3 Dec 2013 11:42fragri schrieb:
Hello everyone,
I'm not sure if the operating costs are really that low.
After all, the ducts of a controlled residential ventilation system need to be cleaned, right? Yes, if no filters are used. Otherwise, you might only need to clean them every 10 years or so...
I read in a report that a poorly maintained controlled residential ventilation system can become a breeding ground for germs. The purpose of that report was to make you believe that. Filters also need to be replaced quite often.
I think the annual cost could easily add up to 200 - 300 € (220 - 330 USD), excluding electricity! The costs vary. Some people sign a maintenance contract with a technician who regularly replaces the filters. Others buy the filters themselves and replace them. Another group buys filter material by the meter, cuts it to size, and replaces it themselves. Costs range from just a few euros to a few hundred euros. There is no upper limit, as it depends on the customer.
I think you can ensure a healthy indoor climate by choosing wall constructions that can absorb and release moisture, for example.Such a wall has yet to be invented. Usually, those who think this come back a few years later with “little problems.”
D
DerBjoern3 Dec 2013 11:45fragri schrieb:
Hello,
Certain building materials can regulate moisture, for example, clay bricks or calcium silicate bricks, at least that’s what several experts I know have explained to me.
If the house is completely airtight on the outside, for instance due to an external thermal insulation composite system (ETICS), this effect obviously won’t work. However, if you use a vapor-permeable insulation (cavity insulation), the wall can "breathe" while still providing insulation.The moisture that diffuses outward through your clay and calcium silicate bricks is only a tiny fraction (per mille) of the moisture generated inside the house. Moisture can only be effectively removed by ventilation!
N
nordanney3 Dec 2013 11:50fragri schrieb:
Hello,
for example, certain building materials can regulate moisture, such as clay bricks or calcium silicate bricks. At least, this is what several professionals in my circle have explained to me.
If the house is completely sealed on the outside, for example with an external thermal insulation composite system (ETICS), this naturally doesn’t work. But if you use a vapor-permeable insulation (cavity insulation), the wall can "breathe" while still providing insulation. Unfortunately, the all-in-one perfect solution has not been invented yet.
Costs are certainly relative, but nowadays you quickly lose your warranty if you don’t have a maintenance contract in place!
Personally, I believe that if you pay attention to building physics, you can manage quite well in a building without a mechanical ventilation system with heat recovery.
Unfortunately, many general contractors / main contractors often focus more on price than on the performance of building materials. In those cases, you of course have to install a mechanical ventilation system to fix the resulting problems. I know several people who have been involved in construction for many years (from civil engineers to architects to university professors specializing in building construction), and almost all of them have told me that for our building project, we can easily do without a mechanical ventilation system—provided we choose the building materials correctly.
That doesn’t mean we will be building any cheaper, though!
Personally, I believe that if you pay attention to building physics, you can manage quite well in a building without a mechanical ventilation system with heat recovery.
Unfortunately, many general contractors / main contractors often focus more on price than on the performance of building materials. In those cases, you of course have to install a mechanical ventilation system to fix the resulting problems. I know several people who have been involved in construction for many years (from civil engineers to architects to university professors specializing in building construction), and almost all of them have told me that for our building project, we can easily do without a mechanical ventilation system—provided we choose the building materials correctly.
That doesn’t mean we will be building any cheaper, though!
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