Replacing a bathroom extractor fan - harder than it looks or straightforward job

[DiamondDallas86]

Old bathroom extractor fan is dying. It hums and occasionally stops mid-run. I can see it is a basic round ceiling mounted unit wired into the light switch circuit. Have done general DIY including some basic electrical work like changing sockets and light fittings. Is replacing like-for-like on a bathroom fan something a competent DIYer tackles or is the bathroom environment enough to make this notifiable electrical work in the UK that needs a Part P registered electrician?

[Glenn]

In England and Wales replacing like-for-like in a bathroom is Part P notifiable if you are working on a new circuit but replacing an existing fan on an existing circuit in the same location is generally considered maintenance and does not require notification or a registered electrician

[DotEXE]

Turn the breaker off, check with a tester before touching anything, match the wiring connections exactly from the old unit and make sure your replacement fan is IP rated for bathroom use. Zone 1 and 2 in a bathroom require at least IP44

[BretHart_X]

The hardest part is usually the ceiling void access if the old unit is ducted. If it vents through the ceiling into the loft you need to make sure the replacement duct connection is airtight or you will get condensation issues in the roof space

[GhostRider14]

Timer fans are worth the small extra cost when you are already doing the job. The built-in timer means the fan runs for a set period after the light goes off which dramatically reduces bathroom condensation long-term

[DecentBloke]

Check the duct diameter before you buy anything. Most domestic bathroom fans use 100mm or 125mm ducting but if your run is longer than 3 metres you want the larger diameter to maintain airflow

[Matt_81]

If there is any doubt about the wiring condition in the ceiling junction box once you get up there, stop and get an electrician to check it. Junction box connections in bathrooms deteriorate with the humidity over time