Bathroom Extractor Fans - a DIY Guide, by Charlie DIYte (CharlieDIYte) on YouTube. 26 min 38 s.
- Video length
- 26 min 38 s
- Time to do it
- 2 hours
- Difficulty
- Medium
- Steps
- 9
What you need
Steps
Measure your bathroom in cubic metres by multiplying length by width by height. Match that volume to a fan with a suitable extraction rate, usually at least 15 litres per second for a small bathroom.
Check where your bathroom sits in the UK wiring zones. A fan inside zone 1 or 2 must be a low-voltage or specially rated unit, and any mains work may need a qualified electrician.
Decide between an axial fan for a short straight duct, a centrifugal fan for a long or bendy duct, and an inline fan mounted in the loft for the quietest result.
Turn off the fan circuit at the consumer unit and prove it is dead with a voltage tester before touching any wires.
Remove the fan cover and unscrew the unit from the wall or ceiling. Note which wire goes to live, neutral and the switched live from the light.
Check the new fan fits the old hole and duct. Enlarge the opening or adapt the ducting if needed, and make sure the duct runs outside, not into the loft.
Wire the new fan to the same terminals, matching live, neutral, switched live and earth. Use the wiring diagram supplied with the fan.
Fix the fan to the wall or ceiling, refit the cover and seal around the edges so air only moves through the duct.
Restore power and test the fan with the light switch. If it has a timer or humidity sensor, adjust the settings with a small screwdriver.
Tips and common mistakes
Never duct a fan into the loft space, as the moisture will cause damp and mould.
A fan with a humidity sensor or timer runs on after a shower and keeps the room drier.
Check the extraction rate against the room volume, since an undersized fan will not clear steam.
If you are unsure about the wiring or bathroom zones, get a qualified electrician to do the connection.
Questions
Do I need an electrician to replace a bathroom fan?
If you are simply swapping a like-for-like fan on an existing circuit, many people do it themselves. Any new circuit or work in the bathroom zones should be done or checked by a qualified electrician under Part P.
Axial or centrifugal fan, which should I pick?
Choose axial for a short, straight duct of under a metre or so. Pick centrifugal or inline for longer runs or ducts with bends, because they cope with higher pressure.
How do I know what extraction rate I need?
Work out the room volume in cubic metres and aim for a fan rated to change the air several times an hour. Fan guides list suitable rates for typical bathroom sizes.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
