Replacing a bathroom extractor fan: can you do it yourself?

Why the fan is grinding, humming, or has stopped altogether

Most fan failures come down to dust and grease built up on the impeller blades over years, which throws the fan off balance and makes it grind or rattle rather than spin cleanly. Bathrooms in blocks of flats especially collect a felt-like layer of dust on the blades and housing that a vacuum with a brush attachment or a damp cloth can often shift.

If cleaning does not quieten it, the bearings have usually worn out. Some fans have replaceable motor cartridges, most do not, and by the time a fan is rattling on worn bearings it is normally cheaper to replace the whole unit than to chase parts for a model that may no longer be sold.

A fan that has stopped completely is either a dead motor, a tripped connection, or a seized bearing that stalled the motor and eventually burned it out. If the extractor is on the same circuit as the bathroom light and the light also misbehaves, that points away from the fan itself and towards the wiring, which is worth knowing before you buy anything.

The mounting types you will find in Estonian bathrooms

Panel flats from the Soviet era usually have a fan set into a duct that runs to a shared ventilation shaft, held in with spring clips or screws into a plastic collar that is already built into the wall. These are usually the simplest to swap because the duct connection is fixed and standardised across the building.

Wooden houses in Kalamaja or Nõmme and newer developments more often use a fan ducted individually through an outside wall or up to a roof vent, mounted either on a plate screwed directly to plasterboard or tile, or clipped into a ceiling cut-out. The mounting method decides what tools you need and how much you will need to patch afterwards.

Before buying a replacement, take the old fan's diameter, depth, and mounting type with you, or better still take the fan itself to match it. A new fan that is a different diameter to the existing duct spigot creates a job that did not need to exist.

Checking the duct connection before choosing a new unit

Pull the old fan out (after isolating power, see below) and look at what it was actually connected to. A short flexible duct clamped with a jubilee clip to a wall spigot is the easiest case: any new fan of the same diameter will clip on the same way.

If the duct is rigid plastic pipe glued or pushed directly into the housing, measure its outside diameter carefully, since the common sizes in Estonian bathrooms are 100 mm and 125 mm and the two are not interchangeable without an adaptor. A mismatch is the single most common reason people end up returning a new fan.

Check the duct itself while it is exposed: if it is crushed, disconnected further along, or blocked with the same grease and dust as the fan, a new unit will not solve the underlying airflow problem. That is the point where a fan swap will not be enough on its own, which the next sections cover.

The swap itself, when it is a simple plug-in fan

Many bathroom fans, particularly those fitted after the 2000s, connect via a plug that sits behind the fan housing and disconnects from a permanent flex, rather than being hard-wired to loose conductors. If yours is like this, the job is genuinely DIY and takes under an hour.

Switch off the circuit at the consumer unit, not just the wall switch, and confirm it is dead with a voltage tester before touching anything. Unscrew or unclip the old fan, unplug the connector, pull the unit clear of the duct, and note which wire went where even though the plug should make this self-explanatory.

• Isolate the circuit at the consumer unit and test it is dead
• Remove the old fan and unplug the connector
• Fit the new fan's duct collar to the existing ducting, using an adaptor if diameters differ
• Plug in the new connector and secure the fan to its mounting plate or clips
• Seal any gap around the duct spigot with a smear of silicone
• Restore power and run the fan for a few minutes to check it is quiet and secure
• Check for any smell of hot plastic or dust burning off, which settles after the first run

When it stops being a fan swap and becomes an electrical job

If the old fan has no plug and its wires go straight into a junction box, or straight into the ceiling rose alongside the light, you are into house wiring rather than appliance swapping. Getting the live, neutral and switched-live conductors wrong on this kind of fan can leave the light and fan cross-wired or leave a live conductor exposed.

The same applies if you need to add a fused connection unit, if the fan is meant to be wired to run on a timer or humidity sensor rather than the light switch, or if there is no isolator switch near the fan at all. Bathrooms also carry extra rules on what can be installed within reach of a bath or shower, which is not something to guess at.

This is where we would send an electrician rather than a fan, and it is priced as electrical work rather than a fan swap, from 49 € per hour. It is a short job for someone who does it daily, and it is the difference between a fan that runs safely for years and one that is a hazard behind a bathroom wall.

When a new fan alone will not solve the problem

A brand new, correctly wired fan will not fix condensation and mould if the duct behind it is crushed, disconnected, or simply too long and winding to move air properly, which is common where a previous owner boxed in pipework without thinking about the vent run behind it. Our separate guide on damp and mould in bathrooms covers how to check whether ventilation generally, not just the fan, is the cause.

If the extraction problem is tied into a wider renovation, such as moving the fan's position, retiling, or dealing with damp that has already got into plasterboard or timber, it is worth treating as one job rather than three separate call-outs. Our bathroom renovation service, from 3 500 € per job, covers exactly that kind of combined work with one guarantee across it.

As a rule of thumb: clean the fan first, check the duct connection second, replace the fan yourself third if it is a plug-in unit, and call an electrician the moment you are looking at bare wires rather than a plug.