Where Is the Best Place to Put an Inline Fan

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Where Is the Best Place to Put an Inline Fan

Inline fans have the unique feature of being installed within the ducting itself, making it a great option for those looking for flexibility in their building operations.

But does that mean they can be installed anywhere in a room? Or are there still certain things to consider to make sure you’re still getting the best out of the fan?

In this blog, we will provide answers to the question ‘Where is the best place to put an inline 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.

Are inline extractor fans the same as a regular extractor fan?

Are inline extractor fans the same as a regular extractor fan?

No, and yes. They share similarities, but approach them differently. The main difference between an inline extractor fan and a regular extractor fan lies in their installation and functionality. Here’s a breakdown of the key distinctions:


  • Inline Extractor Fan: Installed within the ductwork network, typically hidden away in the loft space or ceiling void above the room. Only the duct grilles are visible in the room and externally.
  • Regular Extractor Fan: Mounted directly onto a wall or ceiling within the room itself. The entire fan unit is visible.


  • Inline Extractor Fan: Generally more powerful than standard fans, making them ideal for high-moisture areas like bathrooms and kitchens. They can efficiently handle longer duct runs with bends due to their design, unlike standard fans that struggle with long or bent ducts.
  • Regular Extractor Fan: They are suitable for smaller spaces or situations where shorter duct runs are possible. However, they may not be as powerful as inline fans.

Additional factors

  • Inline fans can be quieter as the unit itself is located outside the room. However, ductwork can contribute to noise. Specifically, not using rigid ducting.
  • Inline fans offer more flexibility in design as the unit is hidden, allowing for a cleaner look in bathrooms and kitchens.

Overall, inline extractor fans are a powerful and versatile solution for ventilation, particularly in situations with long duct runs or high moisture levels. Regular extractor fans are a simpler and more affordable option for smaller spaces or where short duct runs are feasible.

Where is the best place to put an inline fan?

Because an inline fan is placed within the ducting itself, does that mean the inline fan would be appropriate to put anywhere? Not exactly, the area of installation may vary depending on the room it is installed in, let us explain.


When it comes to bathrooms, it would be beneficial to install the inline extractor fan in the loft or ceiling void, directly above the shower or bath. This allows the fan to extract the most steam in the quickest manner possible, as it is as close to the source of the steam as possible.

When it comes to the ducting, running it from the fan unit to a vent positioned on an external wall is mandatory.


Similarly, in bathrooms, it would be advisable to install inline extractor fans above the hob or cooker unit. However, there is more room for choice with this option if you already have a cooker hood in the aforementioned area.

Either option will ensure that steam, smoke or smells will be captured by the inline fan or cooker hood as quickly as possible. Once again, ducting must lead from the fan unit to an external wall vent to expel the extracted air outside.

When it comes to installation, don’t forget…

  • The shorter the ducting runs, the less resistance to airflow and more efficient the fan will be. If possible, ensure your ducting is as short as possible, and as straight as possible, with little to no bends if it can be helped.
  • Make sure the fan unit is accessible. Placing it in the loft can be essential to making any maintenance or the changing of settings extremely streamlined and easy.
  • Although you can install the ducting for the unit yourself in most cases, any electrical installations must be completed by a qualified electrician. By not doing this, you run the risk of legal consequences, in addition to your home being at risk of power outages and electrical fires.
  • Speak to a qualified installer for the best results.
  • If possible, using rigid ducting is the better option for an inline fan, as it reduces noise output.

Can inline fans go anywhere in public buildings?

In theory, yes. However, when it comes to buildings with access from the public or a work space, the installation of inline fans should have some consideration in order to reap the full benefits of this extractor.

Simply put, installing an inline extractor fan in areas that are likely to accumulate humidity, such as bathrooms, kitchens, common areas etc is the best course of action.

Can mould grow in ventilation?

Can mould grow in ventilation?

Yes. Even if you have an inline extractor fan, mould has the potential to grow in, on, or around ventilation. However, this can only happen for very specific reasons.

As we are aware, mould should be less of a worry if you have ventilation, so what can cause it to grow on them? Here are the common causes that make this happen…

  • The ducting is compromised via a tear.
  • The area housing the ducting and ventilation is developing mould due to outside leaks or leaks coming through the internal structure.
  • Mould has been left to develop in the building without ventilating.

Please understand that ventilation units are a tool used to prevent the occurrence of mould. If your ventilation practice is not enough, or some leaks are beyond your control, mould can still appear.

Mould surface cleaners are one of the most effective options in killing mould.

It is in your best interest to remove mould as quickly as possible, as it has the potential to create or worsen health conditions. Symptoms can vary between cold-like symptoms to severe rashes and swelling.

Even being exposed to a small amount of mould will eventually begin to affect your health, so as soon as you see it, get rid of it!

Buy an inline extractor fan today

Buy an inline extractor fan today

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.

Within this blog, we hope to have shown you have answered the question, ‘Where is the best place to put an inline fan?’ Whilst providing you with supplementary information to help you, moving forward.

We understand you may have more questions, do not hesitate to contact us for more information about whatever you require 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:


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Sunday: Closed

15 St John’s Parade

Sidcup, Kent

DA14 6ES

United Kingdom

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