I have a bathroom ceiling extractor fan that comes on with the light and also has an isolator, which obviously turns it off. It now doesn’t work so it needs replacing. What do I need to know? Are there loads of different types? Do I need to check the pipe diameter or are they all a standard size? I’m also thinking of a drimaster in the future so do I need to take that in to account at all?

Check the size of your bathroom and then use one of the online calculators to decide how big a fan you need/want.

There are loads of different types and different sizes and some are noisy while others are very quiet.

I’ve just fitted a large fan (150mm diameter) in our bathroom – mostly because it’s big enough to need the air flow that only a 150mm fan can give. It has reduced the humidity in the upstairs of the house, which makes it a nicer place to be and reduces water damage to soft furnishings etc… and reduced the condensation on the windows when it’s cold outside.

Online Fan Calculator

Thanks for the assistance. Pretty sure I need something like this, but will check the old one first.

http://www.envirovent.com/trade/products/silent-fans/silent-100/