The Domus EasiPipe Cowled Wall Outlet 100mm White (4902W) is a weatherproof external duct termination designed for the Domus EasiPipe 100 rigid round duct system and compatible with all standard 100mm round ducting. The shaped cowl hood deflects rain and wind away from the duct aperture, while the integrated backdraught damper closes automatically when the fan is off, preventing cold air, moisture and insects from entering the duct run. Available in white, it suits rendered, masonry, weatherboard and UPVC cladded external walls. The round spigot connects directly to rigid or flexible 100mm duct by male connection, and the 155×155mm face plate provides a neat, professional finish on the external wall surface.
100mm
Duct connection
155×155mm
Face plate
Cowled Hood
Rain protection
Damper
Backdraught shutter
EasiPipe
System compatible
EasiPipe 100 System Compatible: The 4902W is part of the Domus EasiPipe 100 modular round duct range, which uses consistent 100mm male/female connections throughout — straight sections, bends, tees and all grilles connect without adaptors. It is also compatible with other brands' 100mm rigid and flexible duct via standard push-fit or jubilee clip connection.
Installation Note: The damper shutter and its mounting in the cowl must be installed correctly orientated for gravity-assisted closure. The cowl hood must face upward (outlet pointing away from the wall, hood over the top) and the face plate fixed flat against the wall with exterior-grade fixings and silicone sealant around the perimeter to prevent water ingress at the wall junction.
Cowl Hood Design
The projecting cowl creates a sheltered zone directly in front of the duct outlet, deflecting rain and wind-driven precipitation away from the opening. This is particularly valuable in exposed elevations, gable ends and coastal locations where direct rain impingement on a plain grille can force water into the duct run. The cowl also reduces wind-induced pressure fluctuations that can rattle spring-loaded shutters.
Integrated Backdraught Damper
The removable backdraught shutter closes when the fan stops, blocking cold draughts, moisture and insects from the duct run. The interchangeable design allows the shutter to be removed for cleaning or replaced. Unlike gravity flaps, the damper is recessed within the cowl housing, giving it additional protection from wind turbulence that might hold a surface-mounted gravity flap open.
Professional External Finish
The 155×155mm white face plate provides a neat square footprint on the wall, covering the core-drilled hole cleanly. The white finish is UV-stable and weather-resistant. The Domus EasiPipe range is used by housebuilders, roofing contractors and ventilation specialists across the UK, giving the finished installation a recognised trade-standard appearance.
Improves Ventilation Efficiency
By reducing air leakage back through the duct run when the fan is off, the 4902W prevents the stack effect from drawing unconditioned outside air into the building. This supports the energy efficiency goals of Approved Document Part L and reduces the heating load caused by uncontrolled infiltration through bathroom duct penetrations.
Technical Specifications
| MPN |
4902W |
| Brand / System |
Domus (EasiPipe 100) |
| Connection Diameter |
100mm (4") |
| Connection Type |
Male spigot (push-fit into 100mm female duct) |
| Face Plate Dimensions |
155mm × 155mm |
| Depth (face to spigot tip) |
100mm |
| Damper Type |
Integrated backdraught shutter (removable) |
| Hood Style |
Cowled (projecting rain/wind deflector) |
| Colour |
White |
| Material |
UV-stable white plastic |
| EAN |
5014662005445 |
| Application |
External wall duct termination |
| Compatible Systems |
Domus EasiPipe 100 and all 100mm round duct |
Frequently Asked Questions
What is the difference between a cowled outlet and a gravity flap outlet?
A cowled outlet (4902W) has a projecting hood that physically deflects rain and wind away from the aperture and uses an internal damper shutter recessed behind the hood for backdraught protection. It is more suitable for exposed or wind-driven rain locations. A gravity flap outlet (such as Airvent 415454) relies on a surface-mounted hinged flap that closes under gravity — simpler and lower profile, but offering less weather protection. For sheltered urban locations, either works well; for exposed elevations, the cowled outlet provides better all-weather performance.
Can the 4902W be used with flexible PVC or aluminium ducting?
Yes. The 100mm male spigot pushes directly into PVC flexible hose, aluminium flexible ducting or rigid round duct sections. Secure with a jubilee clip over the join. The EasiPipe 100 system's consistent male/female connections also allow it to join directly to EasiPipe straight sections and bends without additional adaptors.
How do I seal the 4902W to the external wall?
Fix the face plate to the wall using exterior-grade screws and wall plugs through the mounting holes in the face plate. Then run a continuous bead of low-modulus silicone sealant around the perimeter of the face plate and smooth to create a weather-tight seal between the plate and the wall face. This prevents water from tracking behind the plate and into the cavity at the duct penetration.
Is the 4902W available in other colours?
Yes. The Domus EasiPipe 4902 cowled outlet is available in white (4902W), brown (4902B), cotswold/cream (4902C), terracotta (4902T) and a small number of other colours. Choose the colour that best matches the external wall finish or the existing window and door trim. All colour variants have identical internal dimensions and connection specifications.
