Extractor Fan for Bathroom without a window

10 Apr 2010
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United Kingdom
I live in a flat which does not have a window in the bathroom. My current fan may not be strong enough to extract all of the moist air as the vent from the fan has to pass vertically through approx. 4 metres to exit through pipe on top of roof. Moisture is collecting in the duct behind the fan so I have had to disconnect it. The bathroom measures approx. 8 cubic metres. Current fan is 220-240V, 15W Max.
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So maybe you should get a stronger fan and fit a condensation trap in the duct. I hope that you have a fan with an over-run timer. 15 minutes should be the minimum if there is no window.

Theres a fan size calculator here: http://www.tlc-direct.co.uk/Technical/Ventilation/Ventilation4.html

There's different types. Centrifugal fans with forwarded blades are suited for applications with higher air flow volumes and pressures

Also, make sure there is enough air getting INTO the bathroom. That means a grill somewhere or cut a bit off the bottom of the door. If you don't the fan will be creating a low pressure area in teh bathroom and will not be efficient.

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