Hello
Who else here is building a house like us soon, with very good or high values regarding window insulation and also facade insulation (so a very airtight building envelope)?
We have read that houses that are too well insulated often have insufficient air exchange because natural air circulation hardly takes place anymore. In Minergie-certified buildings, this issue is supposed to be solved with a controlled ventilation system. However, such a system is not planned as standard for us, and we actually wanted to avoid it for cost reasons and other considerations.
Since both of us work full time, the windows will likely remain completely closed for extended periods during the day. My question now is: do we have to risk having permanently poor indoor air quality and an unpleasant room climate in our home, or even moisture problems (wet windows in winter)?
Does anyone have direct experience with this or is an expert in the field?
Who else here is building a house like us soon, with very good or high values regarding window insulation and also facade insulation (so a very airtight building envelope)?
We have read that houses that are too well insulated often have insufficient air exchange because natural air circulation hardly takes place anymore. In Minergie-certified buildings, this issue is supposed to be solved with a controlled ventilation system. However, such a system is not planned as standard for us, and we actually wanted to avoid it for cost reasons and other considerations.
Since both of us work full time, the windows will likely remain completely closed for extended periods during the day. My question now is: do we have to risk having permanently poor indoor air quality and an unpleasant room climate in our home, or even moisture problems (wet windows in winter)?
Does anyone have direct experience with this or is an expert in the field?
H
holly-wood3 Jan 2008 16:28@patbone
Thank you for your quick response. The Minergie requirement did not come from me but from Ulrich Nyffenegger at the Office for Environmental Coordination of the Canton of Bern, during the Minergie conference.
Your statement that a Minergie house can be built with an oil heating system is correct, but it’s important to put that into the proper context. For a Minergie single-family house with oil heating, the percentage share is below 2.5%.
Regarding "mechanical ventilation" or comfort ventilation, there are many prejudices. In our case, the windows are always open during summer, so the ventilation system is turned off. Also, during transitional seasons and in good weather, the patio door is wide open…
Our main concern is ventilation losses—that is, the energy lost which must be brought back into the house. A comfort ventilation system with 85% heat recovery significantly reduces these losses! Controlled ventilation does not require an air conditioning system and does not cause drafts.
I don’t see any problem planning ventilation ducts into a concrete ceiling. This is quite common. Otherwise, there are other ventilation systems—namely decentralized ones. We have such a system installed. Decentralized ventilation units with heat recovery can also be retrofitted. There are various suppliers on the market. Here, for example, is a link to a very interesting website of a German passive house owner.
Thank you for the fascinating discussion.
Thank you for your quick response. The Minergie requirement did not come from me but from Ulrich Nyffenegger at the Office for Environmental Coordination of the Canton of Bern, during the Minergie conference.
Your statement that a Minergie house can be built with an oil heating system is correct, but it’s important to put that into the proper context. For a Minergie single-family house with oil heating, the percentage share is below 2.5%.
Regarding "mechanical ventilation" or comfort ventilation, there are many prejudices. In our case, the windows are always open during summer, so the ventilation system is turned off. Also, during transitional seasons and in good weather, the patio door is wide open…
Our main concern is ventilation losses—that is, the energy lost which must be brought back into the house. A comfort ventilation system with 85% heat recovery significantly reduces these losses! Controlled ventilation does not require an air conditioning system and does not cause drafts.
I don’t see any problem planning ventilation ducts into a concrete ceiling. This is quite common. Otherwise, there are other ventilation systems—namely decentralized ones. We have such a system installed. Decentralized ventilation units with heat recovery can also be retrofitted. There are various suppliers on the market. Here, for example, is a link to a very interesting website of a German passive house owner.
Thank you for the fascinating discussion.
We are planning to install a mechanical ventilation system and certify our wooden house to the Minergie standard.
Mechanical ventilation, however, is not the same as air conditioning! You won’t feel any drafts (unless you turn the system up high!).
As already mentioned, its purpose is solely to circulate air and to reduce energy losses that occur, for example, through window ventilation.
Today’s airtight building envelopes require— as has been pointed out here as well—constant air exchange to prevent moisture damage (also in wooden houses). An architect (not ours) recently told us about his own house, which is ten years old, very tightly built, and lacks ventilation: it developed mold and an unhealthy indoor climate.
We are convinced that it is definitely worth covering the additional costs because mechanical ventilation belongs to today’s (and especially future) standard of comfortable living.
What convinced us most in theory is the HOVAL Homevent system. Is there anyone here in the forum with experience using this device?
Mechanical ventilation, however, is not the same as air conditioning! You won’t feel any drafts (unless you turn the system up high!).
As already mentioned, its purpose is solely to circulate air and to reduce energy losses that occur, for example, through window ventilation.
Today’s airtight building envelopes require— as has been pointed out here as well—constant air exchange to prevent moisture damage (also in wooden houses). An architect (not ours) recently told us about his own house, which is ten years old, very tightly built, and lacks ventilation: it developed mold and an unhealthy indoor climate.
We are convinced that it is definitely worth covering the additional costs because mechanical ventilation belongs to today’s (and especially future) standard of comfortable living.
What convinced us most in theory is the HOVAL Homevent system. Is there anyone here in the forum with experience using this device?
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