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HRV near bathroom fan

Posted: Sun Aug 16, 2020 8:53 pm
by Nathan
Hi Guys, this isnt really electrical so thought I would post it in here

I ended up in a roofspace today and noticed HRV unit near a unvented bathroom fan.
As the accessible roofspace isnt very big it means that any steam from the bathroom will be going though the HRV into the bedrooms and im wondering is there rules about this or is it just bad practice?

The unit would have been put in within the last year, the customer has said that they havnt noticed any difference in condensation.
Cheers

Re: HRV near bathroom fan

Posted: Mon Aug 17, 2020 9:22 am
by AlecK
A bathroom fan extracting to roof space does not comply with NZ Building Code.
But may have been installed before the restruction was in place.
There also used to be non-powered bathroom "fans" that "spun" by the draft of heated damp air into the roof space
In an old-style well-ventilated roof venting a bathroom to roof space was probably an acceptable practice.

Re: HRV near bathroom fan

Posted: Mon Aug 17, 2020 12:38 pm
by Nathan
The house is old enough that the none ducted bathroom fan would have complied when installed, it was the new HRV unit next to it dragging the steam to the other rooms in the house that I thought of as odd.

Thinking about it I assume there is no rules about it though as the current rules would assume that the bathroom fan would be ducted

Re: HRV near bathroom fan

Posted: Mon Aug 17, 2020 2:02 pm
by AlecK
Building Code clause G4 covers ventilation;
about ensuring there is enough of uncontaminated air, and that contaminants - including bathroom moisture - are removed
The Acceptable Solution doesn't allow for contaminants to just be moved to another part of the building.
So while a DVS (regardless of brand) is normally an "extra" rather than a required item for a house, if it has a non-compliant effect then it will itself be non-compliant.
Of course the muppets who sell & install these systems are probably completely unaware of what the BC requires.

Re: HRV near bathroom fan

Posted: Mon May 30, 2022 8:07 pm
by MikeNZ
Hi Guys,
I've seen a lot of this in the last few years, mainly with respect to range-hoods that are supposed to be vented through the roof or out through the wall adjacent to the hob/stove.
Usually the excuse is that the "person" couldn't find the correct transition fitting to go from rectangular to round and just gave up on it. :x

And, for what ever reason, the switchboard is always on the opposite side of the wall to the range-hood, so all the cables are covered in greasy nastiness.
As a Fire-fighter, this is what starts and enables the further spread of fires in roofs, it is absolutely slack that anyone that calls themselves a tradesperson should let a situation
like this occur.

Roof fires are bloody hard to put out as it is, once they get moving, but things like this should not be abetting them.
I, personally as an Electrician would not connect anything like this, that is not vented outside.