What Is the Maximum Length of Flexible Ducts in the UK?

What Is the Maximum Length of Flexible Ducts in the UK?

What Is the Maximum Length of Flexible Ducts in the UK?

Flexible ducting comes in various lengths, and can also be manipulated in order to become shorter. But what is the longest flexible duct you can get? Can you install ducting that comes in a long length without cutting it?

In this blog, we will answer the question ‘What is the maximum length of flexible ducts in the UK?’

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 MVHR 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.

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.

Flexible ducting 101

Flexible ducting is a variation on ducting, as the name suggests, it is flexible, as opposed to the regular round ducting which is solid. Depending on the area of installation, flexible ducting can be better than regular ducting, and vice versa.

The flexible nature of flexible ducting allows it to be manipulated into spaces that can’t support regular ducting. This is ideal for smaller homes and spaces. Generally, any manipulation made to flexible ducting is planned before installation, and done during the installation.

Why would I require flexible ducting?

Flexible ducting is ideal for those with limited space but still require ducting. In some instances, it can also be used as a temporary solution. You shouldn’t have to compromise between the space in your home and the ventilation it requires, this is why flexible ducting can be so helpful. An example of flexible ducting can be seen with vented tumble dryers.

The Pros and cons of flexible ducting


  • It is flexible by nature, which by default makes it easier to install & manipulate post-installation if needs be.
  • Can be installed in tight or confined spaces.
  • Option for transparent ducting to be able to see potential blockages.
  • Can be used as a temporary ducting system


  • Due to the flexible nature of this ducting, there is a higher likelihood of punctures, subjective to placement.
  • Regular maintenance checks should be carried out to guarantee efficiency.
  • Mostly suitable for internal mounting

What is the maximum length of flexible ducts in the UK?

What is the maximum length of flexible ducts in the UK?

The maximum length of flexible ducts in the UK is, 1500 mm. This is specifically regarding installing a flexible duct, which should only be used as the ‘final connection’. In terms of purchase, the ducting we sell can be bought for up to 10 meters of length, depending on the ducting you buy.

Although this is an extremely long piece of ducting, it is not made to be used in one go, the idea is to cut it accordingly. In some instances, one 10 meter piece of flex ducting can be enough to provide ducting for a whole home.

Flexible ducting may be available in longer lengths for industrial applications, but for most home applications, 10 meters should usually be more than enough.

If you are struggling to install your ducting, whether that is cutting it, finding the right way to turn it, contacting a ducting installation service is the best option to use.

Can I use a flexible duct for my entire installation?

No. As we mentioned, flexible ducting should be used in the final connection, it shouldn’t be used as the main ducting component. This is simply because flexible ducting must be supported in order to remain straight. Granted, there are areas in which it needs to have a curve, but for the most part, it has to be straight to ensure greater efficiency as the air moves through.

We understand that areas of installation will vary with everybody, that is why we encourage you to speak to us directly, or contact a ducting installer to get guidance appropriate for your situation.

Why is flexible ducting made from different materials?

Why is flexible ducting made from different materials?

If you have been on the hunt for flexible ducting for a while, you will have noticed by now that flexible ducting can be made from different materials, whether it be aluminium, plastic, rubber, or others. But why is this? Why isn’t it just one material? Does it make a difference?

The answer is that ducting is vital in more spaces than just a home, ducting can be used to transport harmful gasses in industrial areas for example, this is where the various materials come into play.

Each material that is used to make the ducting will have a different level of durability, heat resistance, cold resistance, or neutrality against certain chemicals. This is why there are flexible ducts made from different materials, it is in order to accommodate for the particular usage it will be helping with.

What happens if I use the wrong material for my flexible ducting?

Using the wrong material for flexible ducting could result in some serious issues, depending on what the ducting is facilitating.

For example, if you have a need to transport hot and/or corrosive gasses, and use the wrong material for the ducting, the ducting could stain, become damaged internally, or even burn. This can cause further issues the longer it is left unattended.

To avoid this, make sure you know the purpose of your ventilation, is it specifically for an industrial environment? Or is it for home usage? Knowing this can save you time, money, and energy that would otherwise be spent buying, and eventually replacing, the wrong kind of ducting.

The best place to buy flexible ducts?

I-Sells is a provider of ventilation solutions and everything that comes with it, including ducting. We supply flexible ducting and much more.

Whether it is flexible aluminium or PVC ducting you’re searching for, we have it. Some of our options can also vary in diameter in accordance with your needs. This includes 100 mm and 102 mm in diameter. This also applies to the lengths we have available.

Installing ducting

Flexible ducting or hard ducting can be installed by yourself if you so choose. However, we would only recommend this if you have previous experience in doing this, as one mistake could cause a whole host of issues.

If you do decide to install ducting yourself, please try to at least have guidance from an expert in the field, who can assess your installation.

There are many HVAC technicians that offer a variety of services to help you with your ventilation, whether it be for a business or your own home. This can include ducting installation, depending on whom you visit.

Purchase Flexible ducting

Purchase Flexible ducting

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 ‘What is the maximum length of flexible ducts in the UK?’

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 send us an email, 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 King

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