Bathroom Extractor Alternative

[Adie moore]

I've been contacted by a customer who, after having a fire caused by a extractor fan, wants options on bathroom moisture removal. the subsequent refit included a extractor which is permanently switched off at the fan isolator. the room has no windows though. I know their are building regs around this area and just wondered if anyone had some experience with passive extraction.
cheers, adie

 

[HappyHippyDad]

I remember discussing the best ways of reducing/eliminating condensation in bathrooms a year or 2 ago after a customer was reluctant to have an extractor fan. The outcome was 'heat'. I believe condensation forms because the walls or surfaces are cooler than the temperature in the room so if you can make the walls/surfaces warmer then condensation is less likely to form.

In one clients bathroom (no extractor fan) they have a wall mounted fan heater which certainly stops any condensation forming on that wall, however it still forms on the other walls. Perhaps a better option would be to keep the ambient temperature slightly warmer in the bathroom with a different kind of heater, perhaps a tube heater, perhaps more than one?

 

[HappyHippyDad]

Ps.. here is the old thread, but i'm afraid it's not much help Best way to keep condensation out of bathroom? . The answer is to persuade the customer to have an extractor fan (with good ventilation), and put his mind at rest with regards the fire issue by explaining that you are a professional and it will be fitted correctly.

 

[BroadReach]

Heat alone cannot solve the problem.

If you heat the air in a sealed space, it will absorb more moisture. In a bath room the air will soon become saturated. This will then condense on anything below the dew point of that air. That will be everything else in the room not heated up above the temperature of the air!!

I would suggest go with the advice by HHD above, to fit a fan and go for a quality one.

Please note am a mechanical HVAC engineer not an electrician!!

 

[Adie moore]

yeah, I was thinking it was kind of like trying to reinvent the wheel. she has a extractor fitted at the moment. I will offer her a visual inspection of the fan and electrical test of the circuit. I've not seen the job, she collared me on my drive for some advice. nice old girl and only round the corner, might be my good turn for the ....month.

 

[rolyberkin]

She could consider passive stack ventilation, where is the bathroom? In a passive vent retrofit the problem will normally probably be getting a flue to the roof, info re sizes in approved document F. The other issue with passive ventaliation is that the space will probably be considerably colder than using a fan ad hoc/when required and in the summer does not vent as efficiently as in the winter when it will suck all their warm air out, I think the selling point of a fan is riddance of the smells also!

 

[Lucien Nunes]

Knee-jerk reaction. A point to make is that there is nothing unique about an extractor fan, similar motors and electronics exist in all sorts of things e.g. washing machine & dishwasher that would be left running unsupervised, so banishing the extractor isn't the whole story. Good quality appliances correctly installed are the solution.