Description
Combi flexible ducting is a tough, low-cost way to move air around a grow tent or grow room. It has a PVC outer coating over an aluminium inner layer, held in shape by a high-tensile steel wire helix. It is fully flexible, handles high pressure, and is rated for temperatures up to 140°C.
Sizes
Available in 4", 5", 6" and 8" diameters in 5m or 10m lengths, plus 10" and 12" in 10m lengths. Choose the diameter that matches the outlet on your fan and carbon filter, so air flows freely without a restriction.
- PVC outer, aluminium inner, steel wire helix
- Fully flexible and easy to cut to length
- Rated up to 140°C
- 4" to 12" diameters
Combi or acoustic ducting?
Combi ducting is the budget-friendly choice and works well for intake runs, short extraction runs, and setups where noise isn't a concern. If your extraction runs near living space, acoustic ducting has an insulated, sound-absorbing layer that cuts fan noise noticeably. Plenty of growers use acoustic ducting on the extraction side and combi on the intake.
Fitting tips
- Keep runs as short and straight as you can. Every bend and every extra metre reduces airflow.
- Pull the ducting taut so it doesn't sag or kink.
- Secure each joint with a jubilee clip, and use a duct connector to join two lengths.
- If your fan and filter are different sizes, use a metal reducer.
Not sure what size fan and filter you need? Read our extractor fan and carbon filter sizing guide, or browse extractor fans and carbon filters.
FAQs
Can I cut combi ducting?
Yes. Cut through the foil and PVC with a sharp knife, then snip the wire helix with side cutters.
Is it suitable for hot air from lights?
Yes. It is rated up to 140°C, well above normal grow room extraction temperatures.
Buy from Black Country Systems
We're a family-run hydroponics shop at Unit 2 Black Lake, West Bromwich, B70 0PJ, helping growers for more than ten years. Pop in, call 0121 553 7872 or message us on WhatsApp and we'll help you plan your extraction. Free UK delivery on orders over £94.99, and we price match.






