For maximum efficiency it should be mounted as high as possible (warm air
rises) and opposite the source of air (door, window, whatever) that replaces
the air extracted . If placed too close to the source of replacement air
then local air circulation can be set up which leaves the rest of the room
If the above leaves you spoilt for a choice of sites then consider any
prevailing wind direction on your house. Pointed 'into wind' will mean the
fan spends most of it's time with the anti-draught vanes pushed shut on
Well somebody pointed out on here once that it makes sense not to
position it so that the loo, sink and extractor are all in line, meaning
that the shitty-molecule-laden airflow is sucked from the toilet over
the toothbrush rack and out of the vent.
[And that's just how mine's set up... :-( ]
Mythbusters played with this one, keeping serried ranks of toothbrushes in their
bathroom for a week. On subsequent microbiological analysis, they could find no
contamination of the brushes above background.
Most important is the removal of moisture laden air, so position it close
above shower (if you have one). Otherwise the damp will condense on walls
rather than being removed.
Second most important - get a decent fan not a cheap shed piece of tat.
I have installed Vent Axia 125 inline fan for bathroom and Xpelair 100mm fan
for downstairs toilet - both work well.
I inherited a Manrose 100mm fan in en suite - diabolical!!
If you want to do the job once and be satisfied with the result get quality