ᐅ Ventilation in Summer

Created on: 26 Jun 2014 11:12
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mcburns
M
mcburns
26 Jun 2014 11:12
Hello dear forum!

I just don’t understand... maybe someone can explain this to me?

We moved in a week ago, and I’m currently focusing a lot on ventilation and mold. Still, a few questions remain:

Why shouldn’t I keep windows and doors open for several hours at a time when the weather is nice?
The outdoor humidity is quite low right now, and the sun is shining.
So far, I’ve kept windows and doors open for several hours during the day.
As a result, the indoor humidity (which was often around 80%) sometimes dropped to 40%.
But isn’t that good?
I often read that this kind of ventilation would actually bring moisture into the house.
Where would the moisture come from if it’s dry outside?
It’s said that the air would condense on cold walls. But what exactly is meant by “cold”?
Why should you keep closing the windows repeatedly when ventilating? What effect does that have?
And does it make sense to run the heating during the first summer?

Thanks in advance for your answers 🙂
€uro
26 Jun 2014 13:39
Hello,
mcburns schrieb:
....we moved in a week ago and I am currently dealing a lot with ventilation and mold issues...
That should be done beforehand, not afterwards!
mcburns schrieb:
....Where is it supposed to come from if it is dry outside?..
Dry is always relative, just like relative humidity!
What matters is always the absolute humidity!
Summer outdoor temperature conditions are usually not suitable for managing internal drying issues, especially not in basements (Mollier h,x diagram)!
Best regards.
M
mcburns
26 Jun 2014 17:07
Well, I really tried to write in a way that couldn’t be criticized... guess that didn’t work.
Who says I never dealt with it before?
The previous ventilation method unfortunately didn’t help at all.

...Mollier h,x diagram... why didn’t I think of that 😀 😀
€uro
26 Jun 2014 17:28
[QUOTE="mcburns, post: 65087, member: 16044"]....Who says I never dealt with this before?...[ /quote] Apparently not thoroughly enough, otherwise you wouldn’t have asked for help here! :-)

Best regards
B
BauProjekt14
6 Jul 2014 10:49
Unfortunately, I can't help you with this. I think many homeowners find this topic quite overwhelming.

It's a shame that those who are knowledgeable about it don't contribute.
B
Bauberatung
6 Jul 2014 12:04
BauProjekt14 schrieb:

It's a shame that those who are knowledgeable don't write anything.

This is probably more due to lack of time than unwillingness. Also, the topic requested is one of those "controversial issues"—ask 10 experts and you’ll get 12 different opinions 😉

A "cold wall" should not be understood as a wall being "cold" like a refrigerator, but rather just a few degrees cooler than the air temperature. Humidity (and even the described "dry" summer air still carries moisture) always condenses at the "coldest" spot. Anyone can try this effect in the bathroom if they have an enclosed shower cabin—just close it and take a really hot shower for 10 minutes in a warm bathroom. Then open the shower cabin and watch the bathroom mirror...

I think, without being able to scientifically prove it, that it is better to first let the indoor air absorb the existing moisture and THEN briefly ventilate in bursts to exchange this now more humid air for "new" drier outdoor air.

Regards
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