Hello everyone, the title already describes the problem. Approximately 20% humidity in all living and sleeping rooms. We moved in about two weeks ago. That can’t be normal, right? I expected such low humidity only after 2-3 years, but not right from the start...
The first night in the house was really horrible. On top of that, we have been dealing with colds and coughing the whole time. We now have a humidifier running all night in the bedroom (starting in the evening, about 12 hours total) and wake up with around 35-40% humidity.
Could something be set incorrectly in the mechanical ventilation system with heat recovery, or is this low humidity normal in a new house?
What can we do? Apart from the bedroom, we don’t notice it being a problem in any other room. Enthalpy exchangers are supposed to increase humidity by a maximum of 5%, right?!
Thanks for your feedback and best regards
The first night in the house was really horrible. On top of that, we have been dealing with colds and coughing the whole time. We now have a humidifier running all night in the bedroom (starting in the evening, about 12 hours total) and wake up with around 35-40% humidity.
Could something be set incorrectly in the mechanical ventilation system with heat recovery, or is this low humidity normal in a new house?
What can we do? Apart from the bedroom, we don’t notice it being a problem in any other room. Enthalpy exchangers are supposed to increase humidity by a maximum of 5%, right?!
Thanks for your feedback and best regards
M
motorradsilke6 Mar 2023 14:59WilderSueden schrieb:
You still owe an answer about what your ventilation concept says regarding the nominal ventilation rate and why you think you know better than the experts and that twice that amount is sufficient 😉
Sorry, but in this regard you’re like my girlfriend. Not interested in the basics, no desire to deal with it, but completely convinced of your own opinion The nominal ventilation rate is stated as 0.5. You’re probably right in theory. But apparently, theory and practice differ significantly. As they often do in life.
Why do I believe that twice is enough? From my own experience (we have been living like this very comfortably for 1.5 years) and from others. I studied this before our build, not theoretically, but practically.
And speaking of comparisons: you’re the designer who goes straight from school to university and then thinks you can design something. Sometimes that doesn’t work out in practice 😉
Washing machine might be a bit of an exaggeration. But like a microwave (which I don’t have, by the way), or a water or rice cooker (which I wouldn’t want to be without), maybe.
You really don’t need it, but it’s very practical, saves time, and once you’ve used it for a while, you don’t want to be without it anymore.
You really don’t need it, but it’s very practical, saves time, and once you’ve used it for a while, you don’t want to be without it anymore.
I’d like to bring up two points:
- I doubt that an EWT (Energy Recovery Ventilator) accounts for only 5%. Especially with your extreme values, it’s more likely around 10% or more. Our EWT works very well. Another advantage: with an EWT, the mechanical ventilation system can operate comfortably down to about -7°C (19°F).
So don’t debate whether it makes sense in the long run, but rather: Always use mechanical ventilation with EWT. Buy it immediately.
- The argument “mechanical ventilation versus window airing” ultimately comes down to this: “I ventilate manually less often than the ventilation plan recommends, and therefore I have perfect humidity levels and no problems.” Okay, that’s possible. But in that case, you might as well set the mechanical ventilation to 1/5 of its normal capacity and achieve the same effect. That’s doable—probably better than just window airing, since at least it prevents humidity spikes. If problems occur: that’s your own fault. If not: great. But that doesn’t really have anything to do with the ventilation method itself...
- I doubt that an EWT (Energy Recovery Ventilator) accounts for only 5%. Especially with your extreme values, it’s more likely around 10% or more. Our EWT works very well. Another advantage: with an EWT, the mechanical ventilation system can operate comfortably down to about -7°C (19°F).
So don’t debate whether it makes sense in the long run, but rather: Always use mechanical ventilation with EWT. Buy it immediately.
- The argument “mechanical ventilation versus window airing” ultimately comes down to this: “I ventilate manually less often than the ventilation plan recommends, and therefore I have perfect humidity levels and no problems.” Okay, that’s possible. But in that case, you might as well set the mechanical ventilation to 1/5 of its normal capacity and achieve the same effect. That’s doable—probably better than just window airing, since at least it prevents humidity spikes. If problems occur: that’s your own fault. If not: great. But that doesn’t really have anything to do with the ventilation method itself...
Y
Ypsi aus NI10 Mar 2023 14:32Does everyone here with a mechanical ventilation system really have an earth-to-air heat exchanger (EWT)? Or is this extremely low indoor humidity only typical in KfW 40+ standard homes?
We have now placed 9 hygrometers throughout the house. Humidity is in the low 20% range, except in the bathroom, where it is in the low 30% range. In the bedroom with a humidifier, we average between 41% and 45%.
We have now placed 9 hygrometers throughout the house. Humidity is in the low 20% range, except in the bathroom, where it is in the low 30% range. In the bedroom with a humidifier, we average between 41% and 45%.
W
WilderSueden10 Mar 2023 14:39We don’t have a heat recovery ventilation system because it’s decentralized. It’s set to about 5-6 air changes per day, plus exhaust fans in the bathroom controlled by sensors. The house is also KfW40 standard, built solidly with Ytong blocks. Move-in date is February 11. The current humidity in the study is 56%. Normally, I still open the windows 2-3 times a day to get rid of the moisture from construction. Today it’s raining sideways, so I’m keeping the windows closed instead 😉. It’s completely the opposite situation compared to you.
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