People spend time choosing the right fan and then connect it to whatever ducting is nearest. That is a mistake. The ducting affects airflow, noise and, in a cold Irish loft, whether you end up with condensation dripping back down. Here is how to choose the right duct tube.
Three types of flexible ducting
- The ALD aluminium flexible duct is a lightweight, easy-to-fit tube for standard runs in warm or internal spaces.
- The CFD reinforced flexible duct is a tougher, combined-layer tube for runs that need more durability and better shape retention.
- The IAL insulated flexible duct wraps the tube in insulation. This is the one to use in cold lofts, because it stops warm, moist air from the bathroom or kitchen meeting a cold duct wall and condensing.
Why insulation matters in Ireland
When warm, damp extract air travels through an uninsulated duct in a cold loft, moisture condenses on the inside of the duct. Over time that water pools, runs back toward the fan, and can drip through the ceiling. Insulated ducting keeps the duct wall closer to the air temperature, so the moisture stays as vapour and leaves the building as intended. If your run passes through an unheated loft, choose insulated.
Match the diameter to your fan
Always match the duct diameter to the fan outlet. A 100 mm fan needs 100 mm ducting, a 150 mm fan needs 150 mm, and so on. Narrowing the duct chokes airflow and makes the fan louder and less effective. Our range runs from 80 to 300 mm in lengths of 5, 6 and 10 metres, so you can buy the exact size and length for the job.
Keep runs short and smooth
Flexible ducting is convenient, but every bend and sag reduces airflow. Keep the run as short and straight as you can, support it so it does not droop, and avoid sharp kinks. Browse the full ducting collection to find the right tube.