Acoustic Flexible Ducting — Effective Ventilation, Without the Noise
There's a version of ventilation that nobody complains about — where the air moves freely, the system does its job, and nobody in the building is distracted by the hum, rush, or rattle of ducting carrying air overhead. Acoustic flexible ducting is how you get there.
It's a product to turn to when noise becomes a problem — or, better still, before it does. If you're planning a ventilation system for a space where noise levels matter, understanding what acoustic ductwork does and how it differs from standard flexible ducting will help you make the right call from the start.
What Is Acoustic Flexible Ducting?
Acoustic flexible ducting is a combination duct specifically engineered to absorb and dampen the noise generated by moving air. Where standard flexible ducting simply carries air from one point to another, acoustic ducting actively reduces the sound it carries — both the noise of the airflow itself and the mechanical noise from fans and ventilation units upstream.
Our acoustic flexible duct uses a TFF construction:
- Inner layer: aluminium foil: The aluminium inner core is formed around a spiral wire frame, providing structure, flexibility, and heat resistance. It handles warm, humid air efficiently and holds its shape through bends and longer runs.
- Sound-absorbing layer: between the inner and outer layers sits an acoustic insulation medium — typically a mineral wool or foam layer — that traps and dissipates sound energy, preventing it from transmitting through the duct wall and into the surrounding space.
- Outer layer — polyester sleeve: The tough polyester outer jacket protects the acoustic insulation and inner duct from physical damage, giving the finished installation a clean, professional appearance, whether it's concealed within a ceiling void or partially exposed.
The result is a flexible ductwork solution that moves air quietly — noticeably so, compared to standard aluminium or combination flexible ducting.
Where Is Acoustic Flexible Ducting Used?
Acoustic ductwork earns its place in any environment where background noise is a genuine concern. Here's where our customers typically specify it:
- Offices and commercial workspaces — Open-plan offices, meeting rooms, and collaborative workspaces are particularly sensitive to background noise. HVAC ducting that runs through ceilings and into diffusers can generate a constant low-level hum that affects concentration and comfort. Acoustic flexible ducting reduces that noise significantly, making for a more productive working environment.
- Residential HVAC and whole-house ventilation (MVHR) — In homes, especially those built to modern airtight standards, MVHR systems run continuously. Any noise generated by the system — particularly at terminal points or along connection runs — is noticeable in quiet rooms. Acoustic-insulated flex duct is increasingly used in residential MVHR installations precisely because of this.
Suggested Read:Benefits of Using Flexible Ducting in Homes & Industry
- Hospitality and leisure — Hotels, restaurants, spas, and gyms all have areas where the ambient environment matters enormously. Noisy ventilation ducting is the kind of thing guests notice and remember. Acoustic ductwork is a straightforward way to ensure any noise from your ventilation system stays in the background where it belongs.
- Healthcare and education —Hospitals, clinics, schools, and libraries — are environments where noise control is both a comfort issue and a practical one. Acoustic flexible duct helps meet the expected soundscape these buildings demand.
- Home cinema and recording spaces — For any space designed around audio quality, acoustic ductwork is essential. Standard flexible ducting carries fan noise directly into the room; acoustic duct absorbs it before it gets there.
Acoustic Flexible Ducting vs Insulated Flexible Ducting
This is one of the most common questions we get, and it's a good one — because the two products look similar and are often confused.
- Insulated flexible ducting is designed primarily for thermal performance. Its insulation layer prevents heat loss from warm air travelling through the duct and stops condensation from forming on cold duct surfaces. It provides some incidental noise reduction, but that's not its primary function. If your main concern is energy efficiency, heat retention, or condensation control, an insulated flex duct is the right choice.
- Acoustic flexible ducting is designed primarily for sound attenuation. Its construction is optimised to absorb and dampen airborne noise — both the sound of moving air and the mechanical noise from fans and ventilation equipment. It may offer some thermal benefit depending on the specific product, but noise reduction is what it's built for. If your main concern is keeping your ventilation system quiet, acoustic ducting is the solution.
In short: insulated flex ducting keeps heat in; acoustic ducting keeps noise out. Both are valuable — but they solve different problems. Some installations benefit from both, in which case, combined acoustic and insulated products are available.
Choosing the Right Duct Size
As with all flexible ducting, getting the diameter right is the first step. Common sizes include:
- 102mm acoustic flexible duct— Standard for most domestic applications and smaller HVAC terminal connections.
- 125mm and 150mm — Used for higher-output systems, commercial HVAC connections, and larger ventilation units.
- Larger diameters — Available for commercial and industrial HVAC systems with greater airflow requirements.
Always match the duct diameter to your fan or air handling unit's outlet size before ordering.
Installation Tips for Acoustic Flexible Ducting
Acoustic flexible ducting is installed in a similar way as standard flexible ducting, with a few extra considerations worth keeping in mind:
- Minimise bends where possible. Every bend increases airflow resistance and can create turbulence, which generates noise. A short, direct run will always be quieter than a complex one.
- Use proper acoustic duct connectors and collars. Standard fittings can create gaps or misalignments that undermine the duct's acoustic performance. Use fittings designed to work with acoustic ducting for the best results.
- Seal all joints carefully. Use aluminium foil tape on all connection points. An airtight seal prevents noise escaping at joints — not just air.
- Support the duct properly. Fix acoustic flexible ducting at regular intervals to prevent sagging. A sagging duct generates more airflow noise and can compromise the integrity of the outer jacket over time.
- Connect to anti-vibration mounts where possible. If the ducting connects directly to a fan or ventilation unit, using anti-vibration mounts or flexible connectors at the unit end prevents mechanical vibration from transmitting into the duct run.
FAQs
1. What is acoustic flexible ducting used for?
Acoustic flexible ducting is used in ventilation systems where noise reduction is a priority. It's commonly specified in offices, residential MVHR systems, hotels, healthcare buildings, schools, home cinemas, and any space where the noise of moving air through ductwork would be disruptive or unwelcome. It reduces both airflow noise and fan noise transmission through the duct.
2. How much noise does acoustic flexible ducting actually reduce?
The level of noise reduction depends on the specific product, duct length, airflow volume, and the installation. As a general rule, acoustic flexible ductwork can reduce sound transmission by several decibels compared to standard flexible ducting, resulting in a noticeable reduction in perceived noise levels. For precise acoustic performance data, refer to the product specification sheet.
3. Is acoustic flexible ducting the same as insulated flexible ducting?
No — they're designed for different purposes. Insulated flexible ducting prioritises thermal performance: it prevents heat loss and controls condensation. Acoustic flexible ducting prioritises sound attenuation: it absorbs and dampens airflow noise. While there is some crossover in performance, they are distinct products built to solve different problems. If you need both thermal and acoustic performance, look for a combined acoustic-insulated duct product.
4. Can acoustic flexible ducting be used in residential properties?
Absolutely — it's increasingly popular in residential MVHR systems and whole-house ventilation installations, particularly in modern airtight homes where any fan or airflow noise is very noticeable. It's also used in home cinemas, recording rooms, and any domestic space where background noise is a concern.
5. What sizes does acoustic flexible ducting come in?
Our acoustic duct range is available in the most commonly specified sizes for both domestic and commercial use, including 100mm, 125mm, and 150mm. Check your fan or ventilation unit's outlet diameter before ordering to ensure the correct fit.
6. Is acoustic ducting heat-resistant?
Yes. The aluminium inner layer of our acoustic flexible duct withstands elevated temperatures, making it suitable for use with standard ventilation and HVAC systems. For applications involving very high temperatures — such as commercial cooking extraction — always check the product's rated temperature range in the specification sheet.
7. How do I install acoustic flexible ducting?
Installation follows the same basic process as standard flexible ducting. Connect the duct to your fan outlet or air handling unit using the appropriate collar or connector, route it to the terminal point, support it at regular intervals, and seal all joints with aluminium foil tape. For best acoustic performance, keep runs short and direct, minimise bends, and use anti-vibration mounts where the duct connects to fan equipment.