The Airwise AWFDI102 is a 102mm diameter, 10-metre roll of insulated aluminium flexible duct. The inner core is constructed from a laminated aluminium and polyester helix reinforced with a high-tensile steel wire, delivering a smooth, seamless bore that keeps pressure drop low. An outer glass wool insulation layer enclosed within an aluminium foil jacket prevents condensation on the duct surface in cold installation environments and limits heat transfer between the airstream and the surrounding space. Supplied compressed to approximately 0.6m for storage and transport, it extends to the full 10m on-site and can be cut to any length without special tools.
About Airwise: A leading UK and Ireland ventilation products supplier based in Tetbury, Gloucestershire — known for quality, integrity, and competitive pricing across the full spectrum of ventilation ducting, valves, and accessories.
Insulated
Glass Wool + Foil Jacket
0.6m
Compressed Storage Length
Aluminium / Polyester
Inner Core Material
Why Insulated Flex at 102mm? The 102mm bore sits between the common 100mm and 125mm round duct sizes, making this duct the correct connection piece for fan spigots and systems that specify 102mm (4-inch) connections — commonly found in North American-origin fan units and some MVHR distribution manifolds.
Keep Sections Short & Extended: Even insulated flexible duct should be used in short, near-straight sections. Avoid compression or tight bending — each corrugation compressed or each tight bend multiplies pressure drop significantly. Use rigid duct for main runs and limit flex to connection and termination sections.
Key Features
Aluminium/Polyester Laminate Core
The inner duct is formed from multi-layer laminated aluminium and polyester with an encapsulated high-tensile steel wire helix — providing a smooth, airtight bore that resists crushing better than plain foil duct.
Glass Wool Insulation Jacket
The outer insulation layer prevents the duct surface from falling to the dew point of the airstream passing through it — eliminating condensation in cold loft spaces, roof voids, and unheated service voids.
Aluminium Foil Outer Jacket
The outer foil casing provides a clean, vapour-resistant outer surface that also protects the glass wool insulation from mechanical damage during installation and from moisture ingress over time.
Cut to Any Length
The 10m roll can be cut on-site to any required length using scissors or a sharp knife — minimising offcuts and waste across multiple connection runs of different lengths.
Compressed for Easy Storage
Supplied compressed to approximately 0.6m, the roll is compact to store and transport before installation — extending to the full 10m when required.
No Special Tools Required
The duct can be cut, connected, and fixed without specialist tools — making it suitable for installation by ventilation engineers and competent DIY installers alike.
Specifications
| SKU |
AWFDI102 |
| Brand |
Airwise |
| Diameter |
102 mm internal |
| Roll Length |
10,000 mm (10 m) |
| Compressed Length |
Approx. 0.6 m |
| Inner Core Material |
Laminated aluminium / polyester with steel wire helix |
| Insulation |
Glass wool |
| Outer Jacket |
Aluminium foil |
| Colour |
Silver |
| Typical Applications |
Fan-to-duct connections, MVHR last-metre flex, cold space distribution runs |
Frequently Asked Questions
What is the difference between insulated and non-insulated flexible duct?
Non-insulated flexible duct (plain aluminium foil) has no thermal barrier — in cold spaces the duct surface can fall below the dew point of the extract air, leading to condensation inside the corrugation. Insulated flex adds a glass wool and foil jacket to prevent this, making it the correct choice for any section of duct running through an unheated space.
How do I seal the insulated flex to a fan spigot?
Push the inner aluminium core fully onto the spigot (minimum 40mm engagement) and secure with a worm drive duct clip. Then fold the insulation jacket over the clip, bring the foil jacket to the spigot, and seal the joint with aluminium foil tape to maintain insulation continuity at the connection.
Can this duct be used for supply or extract?
Yes — insulated flexible duct is suitable for both supply and extract runs in MVHR and mechanical ventilation systems. For supply runs it limits heat gain in summer and heat loss in winter. For extract runs it prevents condensation in cold spaces.
What is the minimum bend radius I should use?
As a guideline, do not bend the duct tighter than a radius equal to the duct diameter (102mm). Tighter bends collapse the corrugation, reducing the internal area and multiplying pressure drop. Use rigid bends wherever possible for direction changes.
Is the glass wool insulation safe to handle?
Wear gloves and a dust mask when cutting or handling the insulated section of the duct, as glass wool fibres can irritate skin and airways. Normal installation handling of the outer foil jacket does not require special precautions.
How many metres of this roll will I typically use per fan connection?
A typical fan-to-duct connection uses between 0.5m and 1.5m of flex per end. A 10m roll therefore provides material for between 6 and 12 individual connections, making it economical for multi-fan or multi-room installations.
