Bathroom fan and ventilation grid....

[Lusi83]

I've just made a really thorough job of insulating/draughtproofing my bathroom in the eaves...and bought a back draught shutter for my fan so plan to take off the tape that I'd sealed it up with and start using it!

Have done a diagram to try and illustrate my 'problem'

Thinking that fan needs to have an intake of air otherwise it will be effectively trying to create a vacuum...

Fan is right next to the smallish window and the door - bathroom is long and thin ... read somewhere about having a gap under the door/vent in the door - but that would be pointless as it wouldn't be drawing the air through the bathroom...
Don't want to let cold air in (or pointless going to all the hassle of draught proofing)

Nowhere else to position the fan easily (guess ideally would be over shower and through loft but venting it would be a bit of a nightmare -the facings are effectively 3 story high cos house is on a slope)

Thought about putting a vent/duct through the plasterboard wall next to the bath at the top (black box in diagram) -which would draw air from the top of the stairs - heat should have risen up the stairwell...so at least it shouldn't be too cold air -nor particularly draughty ..

Any thoughts/advice?
Does that sound possible/feasible?
Would it upset building control (who apparently insisted on this fan being fitted)?

Untitled

• Lusi83
• 22 Mar 2011
• 1

 

[DAZB]

In my experience you won't need a fan to draw air into the bathroom just because you have one drawing air and steam out. Even if you spent an hour or more in the room the fan wouldn't remove all the air from the room and leave you looking like a prune, although if you were submerged in the bath for that hour the water might. The fan position would be fine near the window but ensure you have it come on when the light comes on and has a sufficient over-run so it is still extracting after you have finished in the room.

 

[freddiemercurystwin]

5 or 10 minutes with the window open after your shower or bath will do more than any fan will do in a few hours no matter where its positioned. If you have a window use it. Heavy insulation and poor ventilation is the perfect recipe for condensation. You are right about having a gap under the door but this only applies when the window doesn't have a trickle vent. A pain in the backside it may be, but a fan over the shower would be the best bet.

 

[foxhole]

You could put a vent thru wall at top of stairs, will draw warm air from house thru bathroom and across shower area, ideally a fan above the shower expelling thru the eaves.