How to Wire a Bathroom Fan?

How to Wire a Bathroom Fan?

How to Wire a Bathroom Fan?

Bathroom extractor fans require wiring to function, as they are not battery-operated. This means steps must be taken when replacing or installing a new bathroom extractor fan. Dealing with electrical wiring can be dangerous, but can it be done by anyone?

In this blog, we will address the question ‘How to wire a bathroom extractor fan?’

With new buildings being made to be as energy efficient as possible, and the UK aiming for 95% of its electricity usage to be low carbon by 2030, it is imperative to understand how we can make the most of our ventilation. This is where applications such as extractor fans and heat recovery ventilation units come in.

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 MVHR units. Almost all of this is facilitated by ducting.

Do I have to use my bathroom extractor fan every time I use the bathroom?

No. Generally, the usage of a bathroom extractor fan is dependent on the humidity present in the room. If your extractor fan runs manually, make sure to turn it on whilst taking a hot bath or shower, automatic extractor fans have sensors that can detect humidity to start operating.

Bathroom extractor fans also help to get rid of unwanted smells, which can be especially helpful in colder temperatures where you don’t want to open the window to get rid of the smell.

In any case, the method to get the most effectiveness out of your bathroom extractor fan is by using it in conjunction with an open window. The open window allows for an additional exit for humidity and an entrance for cool air to enter, swiftly removing the humidity.

How long should I leave my window open in the bathroom?

This depends on whether your window was open or closed during your hot bath or shower. If it was open, then an additional 10-15 minutes is usually enough. However, if it is closed, you should allow for half an hour minimum. This can fluctuate depending on the temperature and size of the bathroom.

The goal is to not have any condensation settle, this is why opening the window beforehand works so well. Ensuring surfaces are free from condensation reduces the amount of time the window would need to be open.

How to wire a bathroom fan

How to wire a bathroom fan

If you are installing a brand new extractor fan, whether that be in a new space in the bathroom, a building being developed, or replacing an old one, wiring must be carried out by a qualified electrician. Below, we will break down the key reasons why a qualified electrician must inspect and install the wiring.

Wires may be old or damaged

When replacing an extractor fan, sometimes the wiring does not need to be removed or replaced, but only a skilled electrician will be able to notice the signs that indicate sub-par wiring.

Using old or damaged wiring can be a potential fire hazard, along with causing the fan to work incorrectly, or it can affect the circuit board it is connected to.

Uses the appropriate voltage

If you are installing a bathroom extractor fan yourself, you may run the risk of accidentally supplying the bathroom extractor fan with a higher or lower voltage than it is supposed to have. This can cause complications in functionality.

Can spot other potential issues

Due to the experience of a qualified electrician, they would easily be able to spot any incongruencies with the current wiring for the bathroom extractor fan and beyond.

Prevents further issues

Using a qualified electrician saves you the hassle of having to make up for any potential mistakes you make. This means the liability is not on your hands at all, and you can save money that would otherwise be spent on further replacements.

What happens if a bathroom fan is wired wrong?

If a bathroom fan is wired wrong, it will lead to the bathroom fan either receiving more electricity than it should or less. Both pose large issues.

If it is receiving more electricity than it needs, it can damage the fan, wiring and beyond. Doing this also means it will also accumulate on your energy bills. If the fan is receiving less electricity than it needs, it will either not work at all, or work in a very slow manner. This is an issue as an unresponsive or less-than-efficient extractor fan will fail to remove humidity.

Does the area holding electrical wiring need regular maintenance?

Does the area holding electrical wiring need regular maintenance?

No. As long as your wiring is installed correctly, it shouldn’t be able to collect enough dust that would need cleaning off regularly.

That being said, you should endeavour to maintain your extractor fan on a semi-regular basis, ideally 3-4 times a year, unless it collects dust quickly.

Does a dirty extractor fan use more electricity?

An extremely dirty extractor fan that struggles to operate because of the volume of dirt, will not use any more electricity than if it was clean. The electrical output remains the same, the only difference with the dirty fan is that the accumulated dust has become an obstacle that prevents it from moving properly.

Extractor fans for sale

Here are two popular extractor fans that we provide in our extensive range. 

Kair Guardian Power Pro PP100P

The Kair Guardian Power Pro PP100P operates at a rate which can convert to a usage cost of 1p a day. (using 28.00 pence per kWh as comparison). Considering this extremely low running cost, in addition to the affordable pricing, it would be a mistake to not consider this option if you’re on the hunt for an extractor fan.

Here are some additional features of this extractor fan…

  • Anti-vibration gasket.
  • Energy-efficient EC motor.
  • 5-year warranty – 1 year parts and labour, 4 years parts only.
  • EC induction motor with thermal protection.

You can find the full details here.

Greenwood Omnique Smart Extractor Fan With Pullcord Humidistat Timer and SELV Transformer

The Greenwood Ominque Smart Extractor Fan has quite a few tricks up its sleeves, with one of them being the possibility of using 6 different kinds of ventilation, in this one unit. Regarding its running costs, it boasts such low energy costs that continuous usage will equate to less than a single penny a day.

This extractor fan isn’t called smart for no reason, its features allow it to be adaptable to properties that may have a range of tenants at a time with their own ventilation needs. It does not require a contractor to make any amendments or repairs either. For more information on this extractor fan. Click here.

Where to find the best bathroom extractor fans

Where to find the best bathroom extractor fans

At I-Sells, all things ventilation and ducting related is our speciality, we are here to answer the questions we know are common for those new to HVAC and what it encompasses.

We at I-Sells endeavour to ensure our customers have all the information they require before investing in our mould solutions. Be sure to visit our blog page to learn about the vast array of factors and issues surrounding ventilation, mould, condensation, and much more.

We hope to have answered the question ‘How to wire a bathroom extractor fan?’

We understand you may have more questions, do not hesitate to contact us for more information about whatever you need our help with. If you’d like to email us, click here. For other contact options, see below:

Call us on 020 8463 9696

Visit us at our showroom:


Monday – Friday: 8:00 am to 5:30 pm

Saturday: 9:00 am to 12:00 pm

Sunday: Closed

15 St John’s Parade

Sidcup, Kent

DA14 6ES

United Kingdom

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