Ducting Supplies

What size ducting do I need?

Most domestic installations use 100mm, 125mm, or 150mm rigid round ducting. Bathroom extractor fans typically need 100–125mm; kitchen extractors and inline mixed-flow fans often require 150mm or 200mm. Always check your fan's outlet diameter and airflow requirements before ordering. Oversizing improves performance and reduces noise.

Should I use rigid PVC or flexible aluminium ducting?

Rigid PVC ducting is ideal for permanent, efficient installations with minimal bends—it offers superior airflow and durability. Flexible aluminium ductwork is best for tight spaces, temporary runs, and where flexibility is essential. Flexible duct creates more friction and noise, so use the largest diameter practical. Many installers combine both: rigid main trunk, flexible branches to individual outlets.

What is flat channel ducting used for?

Rectangular flat channel (available in 110×54mm, 204×60mm, and 220×90mm) is perfect for routing ventilation along skirting boards, under floors, or through tight spaces where round ducting won't fit. It's commonly used in retrofit installations and whole-house ventilation systems where aesthetics and space constraints matter.

Do I need different fittings for rigid and flexible ducting?

Yes. Rigid ducting uses push-fit connectors, bends, and tee pieces; flexible ducting requires jubilee clips (also called hose clamps) and adaptors to connect to rigid sections or outlet ports. We stock Domus adaptors, 45° and 90° bends, Y-pieces, and eFans jubilee clips in all standard sizes. Always match your ductwork diameter to your fittings.

Can I mix brands of ducting and fittings?

Yes, as long as diameters match. A 150mm rigid Domus duct will connect to a 150mm Systemair bend or adaptor. Always verify measurements before purchase, and ensure all components (ductwork, connectors, flanges, clips) are the correct diameter and material type for your system.

How to size ventilation ducting?

Size ducting according to required airflow (m³/h or l/s), duct length, bends, and acceptable pressure drop. Larger volumes or longer runs need wider ducts to maintain efficiency and reduce noise. Correct sizing ensures balanced airflow and system reliability. Using ducts too small for the airflow, adding too many bends, or reducing diameter mid-run are frequent errors. These increase resistance, noise, and energy use, reducing fan efficiency and overall airflow performance.

What are the three types of ducts?

• Rigid ducting: Best airflow and durability.

• Flexible ducting: Ideal for tight spaces.

• Semi-rigid ducting: Balanced performance and easy installation.
  Choose based on airflow needs and available space.

Is aluminium ducting better than plastic?

Depends on the application. Aluminium ducting offers high-temperature resistance and strength for commercial or kitchen systems. Plastic ducting is lightweight and cost-effective for domestic or low-heat use.