ᐅ Exhaust hood with external vent, sometimes odors from the bathroom in the attic
Created on: 6 Feb 2023 11:31
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Corini1985C
Corini19856 Feb 2023 11:31Hello everyone,
We have a newly built house since 2019. On the ground floor, we have a kitchen with a range hood that vents outside through a wall duct.
Not always, but occasionally, we have noticed that during (longer) use of the range hood with the windows closed, there is a smell coming through the house from the bathroom in the attic (there is also our first floor between, which also has a bathroom). The smell is like a drain odor.
The bathroom on the first floor is currently not in use; we sometimes run water briefly, but basically it has not been used since we moved in. I am not sure where exactly the smell in the bathroom is coming from (whether the shower, sink, or toilet). What we do notice is that when the range hood on the ground floor is turned on and the windows are closed, even if there is no smell, there is a draft coming from the toilet cistern or flush button (but I can’t say if the smell also comes from there when it occurs).
Do you have any experience with this or a logical explanation? Is there something in the construction or installation by the general contractor that could be faulty? What is the cause of this draft or the smell, and what could or should we do?
Thanks in advance
We have a newly built house since 2019. On the ground floor, we have a kitchen with a range hood that vents outside through a wall duct.
Not always, but occasionally, we have noticed that during (longer) use of the range hood with the windows closed, there is a smell coming through the house from the bathroom in the attic (there is also our first floor between, which also has a bathroom). The smell is like a drain odor.
The bathroom on the first floor is currently not in use; we sometimes run water briefly, but basically it has not been used since we moved in. I am not sure where exactly the smell in the bathroom is coming from (whether the shower, sink, or toilet). What we do notice is that when the range hood on the ground floor is turned on and the windows are closed, even if there is no smell, there is a draft coming from the toilet cistern or flush button (but I can’t say if the smell also comes from there when it occurs).
Do you have any experience with this or a logical explanation? Is there something in the construction or installation by the general contractor that could be faulty? What is the cause of this draft or the smell, and what could or should we do?
Thanks in advance
The logical explanation is that new buildings are airtight. This means that an exhaust hood must draw fresh air into the building from somewhere; otherwise, a negative pressure builds up inside, and the hood cannot operate effectively (noisy, increased power consumption, reduced airflow). Existing ventilation systems may go out of sync and be affected. If there is a stove that is not designed as room-air independent, this can even pose a life-threatening risk.
The traps in the mentioned bathroom will be dry, causing the necessary "fresh air" to be sucked into the house from the drainage system. Even if they are not dry, the negative pressure in the building may be so strong that air is drawn through the trap from the drainage system.
Open a window when using the hood to provide the required supply air. Otherwise, convert it to recirculation mode.
In any case, you will need to flush all drains in the unused bathroom with water every few weeks to prevent the traps from drying out.
The traps in the mentioned bathroom will be dry, causing the necessary "fresh air" to be sucked into the house from the drainage system. Even if they are not dry, the negative pressure in the building may be so strong that air is drawn through the trap from the drainage system.
Open a window when using the hood to provide the required supply air. Otherwise, convert it to recirculation mode.
In any case, you will need to flush all drains in the unused bathroom with water every few weeks to prevent the traps from drying out.
Hello,
On the contrary, this shows that you have an excellently airtight house.... Seriously, the exhaust hoods draw such a high volume flow that you should actually open a window in the kitchen as well. Otherwise, air will be pulled in and out through every corner, and even the bathroom drains can become a source of forced ventilation.
Best regards,
Andreas
Corini1985 schrieb:
Is there anything to criticize about the main contractor’s work or anything else here?
On the contrary, this shows that you have an excellently airtight house.... Seriously, the exhaust hoods draw such a high volume flow that you should actually open a window in the kitchen as well. Otherwise, air will be pulled in and out through every corner, and even the bathroom drains can become a source of forced ventilation.
Best regards,
Andreas
Corini1985 schrieb:
I'm not sure where the smell in the bathroom is coming fromThen try googling Kittybob (the construction infotainment podcast) Episode 07 "the incense stick affair" – it might help you ;-)https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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Corini19856 Feb 2023 16:09Thank you all for your replies!
@11ant: I listened to it and that could indeed explain the wind coming from the push button, but if this is not actually a defect and it just comes down to ventilation, I think we can live with that.
Thanks again to everyone.
@11ant: I listened to it and that could indeed explain the wind coming from the push button, but if this is not actually a defect and it just comes down to ventilation, I think we can live with that.
Thanks again to everyone.
Corini1985 schrieb:
I listened to it once, [...], but if it's not actually a defectIf you listened to it till the end: yes, it is a defect, but it can be fixed as well.https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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