Extractor fan help understairs wc toilet

[swilli88]

Hi there,

I was hoping for some help picking extractor fan for an understairs wc I am building.

It’s a max 5m3 room and the duct run needs to be about 4.5-5metres (possibly reducing to rectangular ducting for a section to get through a small void).

Will any axial fans be sufficient for this purpose? Iv read some articles about how centrifugal or inline fans should be used for runs this length but I know they are also talking about large bathrooms with showers and baths so I just need clarity for a tiny understairs bathroom to remove odours only. Would a stronger than required axial fan be enough?

Any help would be appreciated

 

[swilli88]

Thanks winston. Was hoping that by posting in a couple places that I would get activity on at least one, but the more the merrier if you can offer any different spin on the topic? Thanks

 

[Mottie]

We don't have an extractor fan in our downstairs bog - wifey says its for number ones only. Little does she know what I do when she leaves for work.

 

[Mottie]

We keep this in there for emergencies.

 

[swilli88]

Haha very good @Mottie yes mostly number ones but the option be nice without needing to fumigate all downstairs

@winston1 no window unfortunately, party wall with neighbours

can inline fans be installed pretty much at the wc vent or do they have to be in the middle(or close to middle) on the run?

 

[JohnD]

Middle is best but they work anywhere.

It needs to be readily accessible for future maintenance.

Have it come on with the light switch plus a timer. The good ones have a ball-bearing motor and are very quiet.

 

[swilli88]

So the plan with the understairs toilet would be to have a small flat ceiling where the stairs comes to a point underneath with the wall. This would create a void above to house a fan.

ideally a centrifugal that I could recess as that is presumably easier to access that an inline fan?

 

[JohnD]

Inline is usually more powerful

You will need some kind of hatch or panel

Possibly hinged to swing down

 

[swilli88]

just out of interest, to bring this back to facts about the room.

the room is max 5m3 which means on paper it needs the most minimum powered fan to turnover 3 x the room in an hour @ about 15m3 per hr or 4litres/second
it is just a toilet and a basin so very little moisture to remove (no shower or bath or anything)
essentially the only reason for the fan is for occasional number 2 odour removing and thats it.
if the room was near a wall i would be getting the smallest and quietest axial fan possible because requirements are so low

the only thing that has me questioning it is the long run of 5m of ducting. does this even matter for such low requirements? if i just got a strong axial fan would that suffice?

 

[securespark]

We don't have an extractor fan in our downstairs bog - wifey says its for number ones only. Little does she know what I do when she leaves for work.

I put one in my Mum's loo under the stairs, but she has had a ban on number 2s since it was installed. It's a Saniflo loo and she doesn't want poo sullying the blades in case a plumber ever needs to repair or replace it!
Having said that, it has done well. It has never gone wrong and it was installed in 1986!