Connecting Extractor fans (2023)

Connecting Extractor fans (1)

Connecting Extractor fans (2)

Wiring up an extractor fan is a simple process and, if done correctly, you can avoid potential hazards and accidents.

Don't cut corners!

What you may need:

(Video) Bathroom Extractor Fans - a DIY Guide

  • Circuit breaker
  • Circuit tester
  • Chisel
  • Electrical Wire
  • Electrical Screwdriver
  • Plaster

An extractor fan is a mechanical fan that draws away smoke, steam and unpleasant smells from kitchens or other rooms. It is excellent at helping to help remove moisture and unwanted odours from your home or office. The right extractor fan will also help to prevent problems with damp.

Building regulations that came into force April 2006 dictate that extraction ventilation has to be fitted into kitchens built prior to that date. For more information visit the government’s Planning Portal page.

What Size of Fan Do I Need?

You need to choose the type of fan that meets the right extract rates and also suits the installation location e.g some fans, such as inline, will need to be installed halfway between the intake and exhaust vents.

The 3 main types of bathroom extractor fan to choose from are axial, centrifugal and inline. Axial fans are usually the least powerful, but fine for most situations. They should not be ducted more than 2-3m. This means they should really only be installed on a wall with direct access to outside. To duct your fan more than this distance, you need to look at the centrifugal version - more powerful than axial fans and good for bigger bathrooms, but they can possibly make more noise.

Centrifugal extractor fans are generally used in buildings that need elongated ducting. They are popular in commercial and industrial properties and work by turning the air through a 90-degree bend inside the fan which increases air pressure, and therefore the power of the fan.

(Video) How to wire bathroom fan Extractor fan with timer and Fan Isolator

Inline fans can, technically, be either axial or centrifugal but they aren’t installed on walls and ceilings, instead, they’re placed in the void or attic space above a ceiling. They are more powerful than centrifugal fans and are highly capable of providing high performance ducting over large distances.

Whatever fan you choose should include the manufacturer's guidance on install location.

How to install the fan - wiring

Connecting Extractor fans (3)

Installing A Bathroom Fan

  • Find the right CFM (Cubic Feet per Minute) or (Meters cubed per hour) rating for your bathroom. This is the first thing you need to do when installing a new bathroom fan so that you can buy the correct fan strength. Bigger bathrooms might need fans with a higher CFM
  • You need to consider is the sound rating of your new fan, which is measured in sones. New fans generally have a sound rating between 0.5 (very quiet) and 6 (very loud) sones.
  • Location - The location is important. It should be installed at the centre point between your shower and toilet for maximum ventilation. If your bathroom is very large, though, you may need to install more than one fan.
  • Consider the layout of your attic. The fan should be placed in the space between two joists, free from any pipes or obstructions. In the case of replacing an old fan, the best thing to do is put the new fan in the same location (unless you have a good reason for putting it somewhere else).
  • Get your tools
    • Screwdriver
    • Combination pliers
    • Power Drill
    • Pad Saw
  • Get your materials
    • Flexible Duct Pipe
    • Vent Cap
    • Screws
    • Caulk and Wire Nuts/Connectors
  • Get your components
    • Fan
    • Flexible Pipe
    • External Grill


The following method is for reference and ideas on a solution actual installation method will depend on the construction of your home.

1. Installation - Drill a hole for reference and then mark the ceiling. Use your power drill and use an extra-long, 3⁄4 inch (1.9 cm) spade drill bit to drill your reference hole where you intend to place the fan. Measure the vent fan housing.
In the attic, find the reference hole and clear the insulation surrounding it away Using the fan housing measurements ensure the fan will fit in your chosen spot, between two joists.

In the bathroom, measure the fan's intake port. These dimensions will allow youto cut the appropriate sized hole in the ceiling.
Using a framing square and pencil, mark the outline of the fan's intake port on theceiling, using the measurements you just took


2. Using a pad saw, cut out the portion of ceiling you’ve marked. Instead of a jigsaw, you can also use a reciprocating/drywall saw. Using your free hand, support the rectangular piece of ceiling and gently lower it to the floor.

3. Put the fan into position but before you lower the fan into the hole attach a 90-degree duct elbow (to which you will later attach the duct pipe) to the correct outlet port using foil duct tape.
Insert a cable connector through the removable knockout hole on the side of the fan's housing, and then slide the supporting metal brackets into place.Centre the fan over the ceiling hole and lower it into place, ensuring any connection points are correctly orientated.

4. Securing the fan to the joists - Once positioned correctly, extend each of the metal brackets of the fan until they reach the joists on each side of the housing unit. Secure each bracket with drywall screws.

Having secured the fan now take the length of flexible duct pipe and attach one end to the 90-degree duct elbow protruding from the fan housing using the foil duct tape.
(This is a good time to run an existing or new electrical cable through the connector on the housing of the fan. Secure the cable by tightening the screw on the connector but be aware that if your fan includes a light you'll need to use a three-wire cable).

5. Finding a suitable exit point for the duct pipe. Find the shortest, most direct route from the housing fan to the outside. Longer duct pipe means less efficiency from the fan.

(Video) How to replace a bathroom extractor fan (timed), Electrician at work.

It is absolutely essential to vent the fan exhaust outside. Venting it directly into the attic would encourage mould growth and potentially cause the rafters to rot.

6. Attaching the vent cap - For an exit point on the side wall, pick a point between two wall studs and take some reference measurements on the inside so you can find the same point on the outside. Use a 4-inch hole saw to cut through wall from the outside and then secure the vent cap in place.
In the attic, attach the end of the duct pipe to the vent cap's connector duct using the foil duct tape.

7. Wiring the connections in the housing unit - You may need to wire the connections from the attic or from the bathroom depending on the type of fan. Be sure to read the manufacturer's instructions and make certain that the power is off before going any further.
We would always recommend any electrical work should be done by a professional.

8. You’re almost done. Now, attach the grille and plug the blower motor into the electrical receptacle and, using the screws provided, make it secure.
Place the mounting wires of the decorative plastic grille into the available slots in the housing unit, making sure it’s sitting flush against the ceiling -- create more tension by spreading the mounting wires, if needed.
Turn the power back on and test the extractor fan to make sure it's working.

Flexible pipe, if not fitted correctly, can become a trap for condensation and end up full of water! If the flexible pipe is supported and tight this won't happen. If possible use solid pipe

(Video) How to wire bathroom fan UK


Is 2 intake and 1 exhaust enough? ›

In a standard desktop PC, you want at least one intake and one exhaust fan. Some cheaper cases only include a single intake fan on the front of the PC, or a single exhaust fan at the rear. Spend a couple bucks for another fan so you have both.

How should an extractor fan be connected? ›

It should be fitted horizontally to the loft floor and needs screwing in. Attach the ducting pipe to the ceiling vent at one end and the extractor fan at the other. On the other side of the fan, secure ducting to the exterior ventilation (like roof eaves or a wall vent).

Can you connect two extractor fans together? ›

Each fan should have its own duct run to atmosphere. If you try to combine them into a common duct it will bring with it a number of problems, including an unbalanced system with positive/negative air pressures which play havoc with the fan motors and could cause motor failure.

Is 3 intake and 1 exhaust enough? ›

Yes, it is okay to have three intake fans and one exhaust fan. This type of fan setup is often used in PC builds to ensure adequate air circulation and prevent the build from becoming too warm. The intake fans draw air into the case and the exhaust fan expels hot air, which helps keep the components cool.

Is 1 intake and 1 exhaust enough? ›

In most cases, one exhaust fan is sufficient, especially if you pair it with two or more intake fans. Besides, having fewer exhaust fans than intake fans helps build positive air pressure inside the case. As a result, the number of dead spots goes down while the dust buildup is at its lowest.

Is it better to have more intake or exhaust fans? ›

In general, it's better to have more intakes than exhausts in order to maintain positive air pressure, which prevents the build up of dust and keeps air circulating. A good setup is normally to have front and bottom as intake and rear and top as exhaust.

Can you just plug extractor fan in? ›

Do cooker hoods just plug in? Kitchen extractor fans need to be earthed so they can't just be plugged in. At CDA, we recommended the appliance is connected by a qualified electrician who is a member of the N.I.C.E.I.C and who will comply with the I.E.T and local regulations.

Do all extractor fans need to vent outside? ›

Do bathroom exhaust fans have to be vented outside? Yes, it is always a good idea to have your bathroom exhaust fan vent outside. Remember, the purpose of your extractor is to remove moisture from the air. If you simply deposit it in another room or attic, you are potentially just moving the problem to another area.

What is the best position for an extractor fan? ›

Beyond their location in proximity to water sources, an extractor fan should also be sited as high as possible and as far as possible from the source of the replacement air. In practice, this usually means that the fan should be placed high on the wall opposite the internal door to the bathroom.

Are 2 intake fans enough? ›

Yes it will be perfectly fine. Just make sure you have one as exhaust near the back by the CPU cooler, and the other as intake below the graphics card. Adding any more fans will only slightly boost your performance.

Is it OK to have 2 intake and 3 exhaust? ›

Is it okay? Having more exhaust than intake will result in negative air pressure in your case and thus air will be pulled in through unfiltered areas. This way dust will build up quicker and you might need to clean it more often.

Is two intake fans enough? ›

it depends on the TDP of your entire system, if you are using a low powered CPU and no GPU, even a single intake is enough. with that said, depending on the case, 3 intake and 2 exhaust is the preferred comnbination, as there is ample intake and exhaust and still have positive air pressure as there is less exhaust.

How much HP can a cold air intake and exhaust give? ›

A larger combustion = more power. Cold Air Intakes are said to improve your vehicle's performance by 5-20 horsepower. This number will vary depending on the make and model of your vehicle. While this isn't enough power to put you back in your seat, it will give your car or truck a little pep in its step.


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