Bathrooms should be havens of warmth, comfort and hygiene, but there’s one factor that threatens to scupper all that – steam. Every time you have a bath or shower, or even if you fill the sink with warm water, you’re going to create steam.

Unlike the kitchen, though, you probably can’t just open a window. You’ll let cold air in when you’re possibly unclothed, and there are potential privacy issues too. Plus, an open window can simply blow the steam back into the room – there’s no reason why it will naturally go out.

The solution is installing a bathroom fan. That way, you can control the direction the vapour-laden air exits the bathroom. Fresh air will be sucked into the room from the rest of the building or through an air vent, so although you won’t completely eliminate moisture build-ups, you’ll certainly reduce them. So, given the pressing need for a fan in the bathroom how do you go about installing one? Here’s our guide.

Types of bathroom fan

Bathroom fans tend to be placed as near to the shower as possible, as that’s where most steam will be produced. That will usually mean you have a choice of two popular fan types:

  • Ceiling fan
  • Wall fan

Ceiling fans are great if your bathroom is upstairs, as you can direct the steam up and away into the roof space, or preferably towards the eaves where it will enter the outside air. Downstairs showers can have a ceiling fan, with ducting taking the vapour between the floors, but that can be quite disruptive to install. They can also be used where the shower is not next to an outside wall. Ceiling fans can also have lighting installed into them, a neat single solution to two problems.

Wall fans are placed above head height and direct steam straight through the wall and outside. If the shower is not next to an outside wall, and a ceiling fan is inappropriate, it can be ducted to the closest exterior wall instead.

A final type is a fan built into a window pane. They are a little more complex to install, especially with double glazing, and if ever the fan or the glazing is being replaced, the glass and the fan will need to be accommodated, adding time and cost to the job. However, there are occasions where there is no space or structural possibility for a wall or ceiling fan, and these are a decent solution. We won’t be covering this type here as it’s a specialist job.

Switching considerations

Fans can be wired to come on in several situations:

  • Manual: The fan has its own switch and needs to be turned on before a shower, and off afterwards.
  • With the lighting: The fan comes on whenever the bathroom light is switched on. It might switch off with the light, but it can also have a delayed action, turning off a few minutes later to allow more steam to escape.
  • With the shower switch: When the main shower switch is turned on, the fan also comes on. Again, it can switch off with the shower or have a timer to keep it spinning for a few more minutes.
  • Timed: A timer extractor fan turns on and off of its own accord throughout the day regardless of how the bathroom or shower are used.

Fitting a bathroom ceiling fan

Once you’ve decided where the fan is going, and ensured there is a route in the roof space or ceiling void to allow your ducting to take the air to the outdoors, follow these steps:

1. Mark the spot. Check there are no joists in the way (knocking on the ceiling is usually enough – you’ll hear the difference) and mark where your hole needs to be with a pencil. The shape and size of the hole will be shown in the manufacturer’s instructions. Also use a wire detector to ensure there’s no wiring in your chosen spot. To be extra safe, switch off the power at the consumer unit at this stage.

2. Drill a hole through the ceiling. This should be inside your pencil guidelines. You can drill multiple holes if you wish, getting as close to the inside of the line as possible. Now, using a pad saw, cut out the shape of the fan.

3. Push the vent into the hole. Attach it according to manufacturers’ instructions. You might need to go into the loft or lift some upstairs floorboards for this step.

4. Attach the ducting. The ducting should go from the fan to the outside, via the shortest convenient route. You can get flexible ducting which will let you shape it around corners. 

5. Connect to the mains electricity. This is a job for a professional electrician. You will need to know exactly what kind of fan you are dealing with, and the wiring will have to take into account the switching considerations listed above.

6. Test the fan. Now, you can switch the electricity back on and test that the fan operates as intended. Once you’re happy, you can replace any floorboards of loft insulation that you have disturbed in the previous steps.

Fitting a bathroom wall fan

A wall fan can be simpler than a ceiling fan in some respects, as it’s all on one level, so you might not need to pull up floorboards upstairs if there’s existing wiring for the shower that can be used. However, in other ways it’s a bigger job. Going through brick is a tougher task, and you might also be required to remove plaster and/or tiling to connect the wiring if you don’t want visible conduits. The process is largely similar, however:

1. Mark the spot. Check there’s no existing wiring, and decide where you want the fan. Ideal placement is above head height, close to the ceiling, and as far from the bathroom door as possible to maximise air flow throughout the room. Also make sure there are no obstructions on the outside wall, such as drain pipes.

2. Make the hole through the wall. This is the most labour-intensive part of the job, which you’ll do with hammer-action drills, chisels or special drill attachments that can make the hole in one sweep. While you might want to attempt such a task yourself, a builder or mason should have all the tools to do the job in a jiffy, so a look in your contractor’s contact list could be in order.

3. Insert the vent into the hole. Depending on the thickness of the wall, and whether it’s a cavity wall, you might need a ducting pipe cut to the relevant length so that moisture goes straight outside and does not soak into the fabric of the wall.

4. Connect to mains electricity. Always make sure this job is done by a qualified electrician. If you need to remove tiling or plaster, this can be quite a big job, as it’s inevitable that tiles will be broken, so you might have to re-tile the whole shower or bathroom. An alternative is to use conduit that sits on the surface of the wall, and requires no major work. It’s not to everyone’s taste aesthetically, but is a much cheaper and easier way to connect the power. You’ll also need to make sure the switch operates as per the list above, i.e. manual, automatic or timed, and wire it accordingly to any existing circuitry or switches.

5. Test the fan. After you’ve tested that the fan is in working order and switches on and off as required, you can go about attaching conduits and/or plastering and tiling to return the bathroom to normal. Remember to fit the cover on the outside of the wall. A louvred or cowled cover will stop rain and excessive draught from getting into the room.

That’s a condensed version of how to place a fan in the ceiling or wall. You should notice the difference straight away, with less damp and mildew building up in the bathroom. If you’re ready to get going, browse our selection of silent extractor fans from brands such as Envirovent in our Home Collection.