How to Fit a Bathroom Extractor Fan

How to Fit a Bathroom Extractor Fan

How to Fit a Bathroom Extractor Fan

Extractor fans, especially those in your bathroom are extremely important to have in working order, but what if you need to install a new one, what do you do? As the UK’s leading ducting and ventilation supplier, I-Sells always strive to provide the best solutions for our customers and anyone who may need a helping hand when it comes to ducting, ventilation and mould control.

That’s why today we’re going to be giving you a guide on how to fit a bathroom extractor fan. We will also be addressing the need for an extractor fan in your bathroom, whilst showing you the solutions we offer for optimum humidity control in your bathroom.

To prevent mould, fresh air should constantly be introduced into your dwelling daily, as it helps to regulate temperature and reduce condensation. Introducing fresh air can be as simple as having a ventilation routine, or installing extractors or PIV systems. Almost all of this is facilitated by ducting.

I-Sells is here to provide the answers you need whilst also supplying you with all the information you need to combat mould and have a well-ventilated home.

What is a bathroom extractor fan?

A bathroom extractor fan is a small fan that is placed on the wall of your bathroom. Connected to an outside vent, the role of the extractor fan is to facilitate the removal of humid air and smells, and ventilate the air in your bathroom.

Why do we need bathroom extractor fans?

We need bathroom extractor fans because without them, your bathroom will take longer for smells to go, and humid air can settle on surfaces to cause condensation. Opening windows can help to resolve this, but in instances of bad or cold weather, you may not want to open your window all the time.

Prevention of condensation is the main aim of a bathroom extractor fan, if condensation is left, it can easily become mould.

Do I need an extractor fan in my bathroom?


Technically, no. But this depends on your home, UK regulations (specifically ‘building regulations’ document F ) specify that:

  • A UK bathroom must be ventilated by either a window or an extractor fan.
  • If your bathroom has a toilet only, you are fine to use a window alone as your source of ventilation.
  • In new-build bathrooms with a bath and shower, mechanical ventilation is required in the form of an extractor fan. This is because new-builds are built to be more airtight, so natural ventilation is much lower.
  • The ventilation requirements for a bathroom are 15 litres per second/ 54m3 per hour

Bathrooms are where you will accumulate humidity on a daily basis through hot showers or baths, if left undealt with, the moisture will create a perfect environment for mould.

Mould is a fungus known to cause and exasperate an array of health issues, simply wiping it away does not guarantee it is dealt with. Only daily maintenance will keep it at bay, this maintenance comes in the form of opening windows during or after a hot shower or bath, in conjunction with using an extractor fan.

Extractor fans work by expelling unwanted humid air and odours through their venting. Extractors ensure that the air in the room it operates in is not stale and is not host to any lingering smells.

Do you need an extractor fan in your bathroom? Or a new extractor fan? You probably do if any of these signs apply to your bathroom:

  • Mould buildup that always returns despite cleaning it away.
  • The bathroom stays humid and damp for a while after a shower or bath has taken place.
  • There is usually condensation on the window, walls or tiles, bath or sink.
  • Smells linger in the bathroom for a very long time.
  • Mould appears around or under the sink.

If any of these signs are apparent in your bathroom, we suggest you immediately use mould-cleaning products and make a daily habit of opening the window and looking to upgrade or install a bathroom extractor fan. We suggest doing this immediately as prolonged exposure to mould can deteriorate your health.

As we continue, we will be elaborating on the steps needed to install a bathroom extractor fan, if you want to read more about condensation management, and delve into the subject of needing an extractor fan, our blog has a comprehensive array of answers to help you.

Mould explained

Mould, otherwise known as damp, is a fungus that grows on wet surfaces. Mould comes in a variety of colours: Black, Green, Brown, Grey and White. It can be difficult to identify mould by colour as it can occur in many shades. Some of the most common mould strains in the home are:

  • Black Mould – Also called Stachybotrys chartarum, Black mould is commonly found in bathrooms and wet rooms but can also occur on cold exterior walls in habitable rooms such as the bedroom or living room.
  • Cladosporium – Commonly found in bathrooms, under sinks, and around faucets but it can grow on surfaces like carpets, furniture, walls, and floors.

Mould reproduces from tiny spores. The spores float through the air and deposit on the surfaces. Under adequate temperature, moisture, and nutrient conditions, the spores can form new mould colonies.

Mould can severely affect your immune and respiratory system, as the spores are easily breathable and not obvious to see through the human eye.

If you have found mould in your home, you need to assess if this is your landlord’s responsibility (for example it could be from a leaking roof that needs repairing) or if the dampness is caused by improper ventilation. To assess your options, click here.

How to fit a bathroom extractor fan

We will be addressing the subject of how to install a bathroom extractor fan in sections, from the start of the process to installation and maintenance, and is as follows:

Where to position the extractor fan in your bathroom

Knowing where to install an extractor fan in the bathroom depends on the layout of your bathroom, some homes have a separate room for the toilet and bath/shower. In this case, the room with the shower/bath is the best option.

Generally, bathroom extractor fans can be anywhere on the wall as long as it is opposite the door but again is subject to your bathroom structure and the type of extractor you purchase. As long as it is in the vicinity of the window, (but not below a window) or on a wall that leads directly outside (or proceeded by venting that leads to outside) it should be okay. Once you know where to install it, you can proceed.

What you will need:

  • Pencil
  • Tape measure
  • Drill and correct drill bit
  • Flexible ducting
  • Saw
  • Hammer
  • Chisel
  • Safety equipment
  • Screwdriver
  • Mask and gloves & goggles

The Process

  1. Use a pipe and cable detector, and make sure there are no obstructions inside or outside the wall that will block the fan. Do not place the outlet directly below a window.
  2. For fitting a fan in a new place, you have to make a hole in your wall. Once you have made sure the wall is clear, hold your fan in place, and use your pencil to trace around the circular edge of the fan. Mark the centre point on the wall and drill a hole through the wall for reference.
  3. Drill a series of holes around the circular tracing of your fan at around 35mm apart. Once you have done this, use a chisel and hammer to ‘chop out’ the wall within.
  4. After creating the hole, insert the flexible ducting. It should fit at a slight downward angle whilst being flush against the internal and external walls. Trimmings can be made with the saw. (any repairs to plasterwork should be undertaken now).
  5. On the inside wall, fit the fan over the hole and use your pencil to mark where it is secured to the wall. Drill the holes to insert any necessary fittings. Position the fan over these holes and secure it in place with your screwdriver.
  6. Do the same for the outside wall.
  7.  Now it’s time to make the electrical connections, in compliance with ‘Part P’ of UK building regulations, a qualified electrician must make the appropriate connections. If you don’t use a qualified electrician, you can risk damaging the electric circuits in your home, potentially electrically shocking any resident in the home, incurring a criminal fine, and being made to remove the installation.
  8. After making the electrical connections, secure the grill covers over the fan on the inside of the bathroom and on the outside wall. If the cover has a slatted design, make sure to position them horizontally to keep the rain out. (Resourced from

How to replace a bathroom extractor fan

Again, as this process requires electrical work, a qualified electrician must be present when disconnecting the old extractor and reconnecting the new one.

Making sure the new extractor is the same size (or making alterations to the wall if not) follow the guide from step 8. If you are not replacing the venting, be sure to remove any excess dust.

Can I replace a bathroom extractor fan myself?

If you aren’t able to install the extractor fan yourself, it is best to call a qualified electrician. We understand that not all of our readers may have the contacts, or know who to go to when searching for someone to install their extractor fan, Click here to find local, trusted electricians.

Maintenance – How to clean a bathroom extractor fan

We have an in-depth blog specifically about cleaning your extractor fan. Read it by clicking here.

Where can I buy bathroom extractors?

I-Sells provides a variety of bathroom extractor fans. Our range is from affordable, to premium, and everything in between. We also supply kitchen extractor fans, ducting, PIV systems, mould control solutions, and more!

Bathroom extractor fan solutions

Kair Smart 100mm Intelligent Extractor Fan with Humidistat Timer & Data Logger

The Kair Smart 100mm Intelligent Extractor Fan with humidistat Timer & Data Logger

Featuring a Humidistat timer, the fan will turn off itself after the room’s moisture level goes beneath a certain level. The fan is double insulated, meaning there is no earth connection. click here to see the full list of features and specifications.

Kair Mini Single Room Heat Recovery Ventilator – White Outer Grille – (min 120mm hole diameter)

The Kair Mini Single Room Heat Recovery Ventilator – White outer Grille – (min 120mm hole diameter) offers higher levels of indoor air quality, it adds fresh & filtered air into your home whilst extracting stale, moist air.

this product can help save money on your energy bills as it recycles up to 81% of heat and energy. To see the full list of features and specifications, head over to our website now.

Kair Guardian Power Pro PP100HTPLV Powerful Centrifugal Extractor Fan

The Kair Guardian Power Pro PP100HTPLV Powerful Centrifugal Extractor Fan features an energy-efficient EC motor, this model can be as quiet as 15.5 decibels, meaning you can have efficient ventilation without the loudness of your standard extractor fan.

To view the full list of specifications and features, our website has all the information you need.

Kair Guardian Power Pro HTP

The Kair Guardian Power Pro HTP using its 100mm powerful centrifugal fan, this model can exhaust through long lengths of ducting up to 15M, showing amazing efficiency despite the low running costs of this model.

For a full understanding of this model’s pricing, features and specifications, take a look at our website.

Kair Guardian Power Pro PP100P

The Kair Guardian Power Pro PP100P contains features such as the EC motor, double insulation and a shockproof, high-quality technopolymer casing. Whilst also being a financially friendly option to anybody on a limited budget.

To view this model and its full list of specifications, our website has all of the information you need.

Want to know which is the best bathroom fan extractor? Our blog can give you all the answers you are looking for.

Do bathroom extractor fans have timers?

Yes, most bathroom extractor fans have timers that stay on for however long you set it to be. However, we also supply models that operate based on the humidity in the room and turn off once it is below its humidity threshold. Some of our extractor options also feature connectivity with your smart device.

Here to help

We at I-Sells endeavour to make sure our customers have all the information they need before making the choice to invest in our products. Be sure to visit our blog page to gain knowledge on the wide array of factors and issues surrounding ventilation, mould, condensation, and much more. We hope to have helped you learn how to fit a bathroom extractor fan.

We understand you may have more questions, Please do not hesitate to contact us for more information with regard to ventilation in your bathroom or kitchen. If you’d like to send us an email, click here. For other contact options, see below:

Call us on 0208 463 9696

Visit us at our showroom:


Monday – Friday: 8:00am to 17:30pm
Saturday: 9:00am to 12:00pm
Sunday: Closed

15 St John’s Parade
Sidcup, Kent
DA14 6ES
United Kingdom

Share this post

Leave a Reply

Your email address will not be published. Required fields are marked *