8″ Window Exhaust Port

Description

8 inch window vent port — terminate the trunk at full size

An 8 inch window vent port exists to stop a common and self-defeating mistake: running a generous 8-inch trunk the whole way across a building and then pushing it out through a 6-inch or 4-inch hole because that was the fitting on the shelf. A restriction at the end of a run acts on the whole system exactly as much as one at the start. If you paid for 8-inch, this is how you keep it.

Flanged plate, 8-inch collar on the inside face, gasket groove around the flange, insect-screen retention on the outer face. It mounts through a panel or a wall penetration and terminates the run without a single reduction. The body is 39 mm deep front to back, so even a 248 mm flange sits close against the panel rather than projecting into the room or fouling a closing sash.

Same through-panel principle as the smaller port, scaled to the trunk size that a hard-working machine, or a shared exhaust carrying two of them, actually needs.

What it fits

Standard 8-inch duct on the inside collar, rigid or flexible. The flange mounts through a window filler panel or a permanent wall sleeve. It takes the trunk side of the 8″ to Dual 6″ Y-Splitter directly, which is what makes a two-machine, one-hole install possible.

If your run is 6-inch, do not oversize the port for the sake of it — use the 6″ Window Exhaust Port and keep the seal tight. If the final approach to the window is flex duct, the 8-Inch Flex Duct Window Vent Port is drawn around that collar instead.

How it is used

Mount it through a filler panel cut to the sash opening, or through a permanent wall penetration if the install is staying. Seat a gasket or foam strip in the flange groove, fix the panel, fit the screen on the outside, and band-clamp the trunk to the inside collar. Because an 8-inch port and a metre of 8-inch duct together carry real weight, support the run near the port rather than letting the panel hold it.

Where the trunk has to turn immediately before the wall, put an 8″ 45° elbow in ahead of the port rather than bending the duct against the panel.

Why full-size termination is worth the bigger hole

Airflow in a duct system is limited by the tightest point in it, wherever that point happens to be. A run that is generous for four metres and then squeezed at the last 100 mm behaves like a squeezed run. That final fitting is also the one place where a restriction makes noise you will actually hear, because it is on the outside of the wall pointing at the neighbours. Terminating at 8-inch keeps both the airflow and the quiet you built the run for.

• Ends an 8-inch trunk at full cross-section with no last-fitting reduction
• Takes the wye trunk directly, so two machines share one wall penetration
• Seals through a removable panel with a gasket groove in the flange
• Retains an insect screen on the outer face
• Doubles as a full-size intake port when a room needs make-up air

Specifications

Open source — take the file, change the flange

Every design in this line is D-Central Technologies’ own — we drew this flange, we open-sourced it, nobody else did — and every one is published under CC BY-SA 4.0 at the 3D models download center: download, modify, remix, print, sell. Straight to this part: the 8″ window exhaust port model. Window openings are the least standard dimension in anybody’s house, so the flange is exactly the sort of thing worth editing yourself.

The file is window_port_8in.zip and it holds the STL, the CC BY-SA 4.0 licence, and the installation and safety guide. This page is for the finished port, made to order in PETG and shipped from Montreal, Quebec, in black or in orange. The drawing costs nothing, now or later; buying the port or giving at D-Central’s fund page is what funds the next one.

Works with

• 6″ Window Exhaust Port
• 8-Inch Flex Duct Window Vent Port
• 8″ to Dual 6″ Y-Splitter
• 8″ 45° Duct Elbow
• 8″ Duct Coupler

One vendor for the shroud, the trunk and the wall: see the D-Central shroud and ducting system.

Frequently asked questions