Condensing Extractor Fan

[Andrew May]

Just replaced an extractor fan in a second floor bathroom with no window and no external wall. This is in a flat.

Connected to the existing pipe and then discovered that the pipe leads into the loft space above and stops there. The loft space is cold and the pipe was full of condensate.

So need to do something to stop all that humid air filling the loft void. What I really need is something that will condense out the moisture so that it can be routed down the soil stack. But while that might work in the middle of winter it is going to need something else in the summer when the moist air will escape before it condenses.

Because it is a flat I probably need to get the freeholders permission to go out through the roof or soffit and it will mean working three floors up so would rather avoid that option.

I guess a dehumidifier in the bathroom is one option (or even in the loft? ) but is there anything else I could be considering.

I have no idea what they do in the flat below which doesn't even have access to the loft.

Andrew

[meow2222]

dehumidifier makes more sense as it doesnt chuck heat out in winter. Doesnt chuck whiffs out though.

NT

[dennis]

I assume you mean throw heat out of the house.

Dehumidifiers chuck out heat into the room, the wattage of the fan and compressor + the latent heat from the condensed moisture. A 20l a day one could be 600-1000 watts of heat if the room is damp. Desiccant ones may chuck out even more heat as they have a few hundred watts of heater in them.

The dehumidifier I have has a carbon filter and a UV light and it removes whiffs quite well. They also remove dust as they invariably have a filter on the air inlet to keep them clean inside.

[Mike Clarke]

Probably dumping all the moist air into the void between their ceiling and your floor :-(

[admay1963]

Its purpose build flats (30yrs old or so) so I think it is a solid concrete floor.

[spuorgelgoog]

Ask the neighbours in case there's a communal duct which has been disused i n your flat.

Or run horizontally to the nearest outside wall. You can get 'high rise' ve nts for tumble dryers which can be fitted from inside with no external acce ss. You'd need to use a fan with integral back draught shutter as those ven ts don't usually have shutters.

Owain

[andrew]

Most basic solution is condensation fittings for the pipe, eg:

A

[Martin Bonner]

Eek!

Yes, but if moist air escapes into the loft in summer, it will probably be warm enough up there not to condense - in which case the moisture is harmless.

[edalerichard]

I have had a very similar problem Was a slate roof, 3 storeys up. I removed a couple of slates from inside and wangled a weathering slate in. Used an extended copper strap to secure the final slate immediatley above the weathering slate Its been there quite happily for 8 years in a very exposed position on the Sheffield hills. Fiddly but beats working so high up. Even if you go this route do add a condensation trap just above ceiling level, and condensation in rest of ducting then goes via overflow pipe to eaves