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There definitely are some subtleties of building science involved. Insulation doesn’t so much keep your house warm (that’s what the furnace does) as keep the ou

There definitely are some subtleties of building science involved. Insulation doesn’t so much keep your house warm (that’s what the furnace does) as keep the outside of your walls cold (at which point they radiate/convect less heat into the air). If the air reaches its dew point at an inopportune place in the wall assembly you can easily get moisture damage and/or mold.

jaclaz 6y ago
Yes, if you want a good insulation you need a mechanical ventilation (with air heat exchanger) otherwise - besides mold - you will be living in a non-healty environment. Even on non particuarly insulated houses our grandmothers and mothers did - at least once a day - change the air, opening windows for some fifteen minutes, there were reasons for that, and they remain valid. Nowadays that tradition is largely lost (for whatever reason) and some way to change air needs to be provided (and it comes with a cost and complications attached). I have seen too many houses built in the early days of energy saving (that began here roughly 10-12 years ago) with serious mold or however humidity issues, and even nowadays, when the issue is (partially) re-known, I see freshly built houses in class B or C (in EU they are classified with the best being A+ and the worst being G) without any mechanical ventilation provisions (houses in classes A/1/2/3/4 now largely have them).
- saeranv 6y ago
  Yeah, the building science/architecture had to go through a painful learning process about mold, and humidity (see the leaky condo crisis in British Columbia[1]). That being said, the consensus in building science circles is now converging to the idea of building airtight buildings (i.e Passive House) with layer air and vapour barriers, along with insulation to manage moisture and heat. That way you don't sacrifice heating to manage your moisture. [1] https://en.wikipedia.org/wiki/Leaky_condo_crisis https://en.wikipedia.org/wiki/Leaky_condo_crisis

jaclaz 6y ago

Yes, if you want a good insulation you need a mechanical ventilation (with air heat exchanger) otherwise - besides mold - you will be living in a non-healty environment. Even on non particuarly insulated houses our grandmothers and mothers did - at least once a day - change the air, opening windows for some fifteen minutes, there were reasons for that, and they remain valid. Nowadays that tradition is largely lost (for whatever reason) and some way to change air needs to be provided (and it comes with a cost and complications attached). I have seen too many houses built in the early days of energy saving (that began here roughly 10-12 years ago) with serious mold or however humidity issues, and even nowadays, when the issue is (partially) re-known, I see freshly built houses in class B or C (in EU they are classified with the best being A+ and the worst being G) without any mechanical ventilation provisions (houses in classes A/1/2/3/4 now largely have them).

saeranv 6y ago
Yeah, the building science/architecture had to go through a painful learning process about mold, and humidity (see the leaky condo crisis in British Columbia[1]). That being said, the consensus in building science circles is now converging to the idea of building airtight buildings (i.e Passive House) with layer air and vapour barriers, along with insulation to manage moisture and heat. That way you don't sacrifice heating to manage your moisture. [1] https://en.wikipedia.org/wiki/Leaky_condo_crisis https://en.wikipedia.org/wiki/Leaky_condo_crisis