Inline Extractor Fan

Think mine are in the middle. :-)

I would suggest noise should be the deciding factor.

Noise is best kept at the source and not above a bedroom. Power may also be another consideration.

I'm not convinced position is significant. If there is a choice then away from any bends. Condensation may also be a factor where moisture will condense and pool, sometimes in the motor housing.

For that reason I might be in favour of combined vent/motor combinations in the affected room rather than an inline fan. Access is also more convenient with less joins.

YMMV

After recommendation here, I bought one of these:

It is screwed to a board across a couple of joists, and there seems to be no discernable direct transmission. The mounting bracket includes some rubber isolation material.

The airflow is far better than the (failed) cheap one it replaced. It can push-fit into the pipework, and is readily removable for cleaning.

Chris

It does not make much difference, but I normally try to have it at a high point so that condensation runs away from it. Really it then just comes down to where you can mount it so its accessible for maintenance, and will keep as much noise away from places you don't want it as possible.

Its not much to choose if its in a constant diameter duct, but if its closer to the outside, it can suffer from the weather a lot more. Brian

That is some price. Having said that, doing the job yourself and properly will be cheaper than getting someone who undoubtedly won't have the same care and consideration.

That is the one that I have to install - except it is the 4inch version. Matches the diameter of the roof vent.