Repair Systems — 07
Window-Mounted Exhaust Fans
Technical product reference for window exhaust fan systems with attenuation screens for window-mounted exhaust fan replacement in Australian Class 2 strata apartment buildings.
What are window-mounted exhaust fan systems?
Window-mounted exhaust fans are axial fans installed directly into window glass to provide powered mechanical exhaust from bathrooms and toilets in buildings where no ceiling void access or wall cavities for ductwork are available. The fan is fitted through a circular hole cut in the window pane and discharges exhaust air directly to the exterior without any ductwork. This makes them a practical option in Class 2 strata apartments where the existing building construction does not permit ducted inline fan installation.
Installation requires a qualified glazier to drill or core-cut a circular aperture in the window glass before the fan is fitted. The fan frame is fixed into this aperture and secured against the glass. An integral backdraft shutter closes automatically when the fan is not operating, preventing cold air, wind and insects from entering through the glass opening. The window frame and glass thickness must be confirmed as compatible with the selected fan model before specifying.
Window exhaust fans provide lower airflow performance than inline ducted fan systems. They are limited to bathrooms and toilets in rooms immediately adjacent to an exterior window and are not suitable where high exhaust rates are required. Airflow adequacy must be confirmed against AS 1668.2 minimum exhaust requirements for the specific room volume and use. Where a room does not have direct exterior window access, or where airflow requirements cannot be met, an inline ducted system must be considered instead.
Do not confuse with:
- Louvre windows — natural ventilation only — not powered exhaust — do not satisfy AS 1668.2 mechanical exhaust requirements
- Wall exhaust fans — mounted through masonry or framed wall, not through window glass — different installation process and substrate
- Inline duct fans — ceiling or duct-mounted, not window glass installation — suited to rooms without direct exterior window access
Product Reference
1 product — 1 brand — window-mounted exhaust fan systems
System Description
The Manrose WF150 is a 150mm square-frame axial exhaust fan designed for direct installation into window glass. The fan discharges exhaust air directly through the glass pane to the exterior, making it suitable for bathrooms and toilets in buildings where ceiling void access or wall cavities for ductwork are unavailable. Installation requires a circular 150mm hole to be cut in the window glass by a qualified glazier prior to fan installation. The integral backdraft shutter closes automatically when the fan is not running, preventing cold air and insects from entering through the glass opening. Window-mounted exhaust fans provide a simple direct-exhaust solution where no ductwork infrastructure exists. Airflow performance is limited compared to inline ducted systems and is subject to the resistance of the backdraft shutter and external wind conditions. Fan selection must be confirmed against room volume and the minimum airflow requirements of AS 1668.2 for the specific wet area application.
Technical Properties
- 150mm axial impeller — direct window glass installation — no ductwork required
- Square external frame suits standard window rebates — circular 150mm glass hole required — glazier preparation mandatory before installation
- Integral backdraft shutter — closes automatically when fan stops — prevents reverse airflow, cold draughts and insect entry
Limitations
- Requires circular hole drilled in existing window glass — this is a specialist glazier operation, not a general trade task
- Toughened (tempered) safety glass cannot be cut or drilled after manufacture — if existing glass is toughened, the entire window pane must be replaced with pre-drilled annealed or laminated glass
- Not suitable for rooms requiring high airflow rates — window fans have lower performance than inline ducted systems — confirm adequacy against AS 1668.2 for room volume
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Technical comparison of window-mounted exhaust fan products. Confirm current product specifications with manufacturer TDS.
| Product | Brand | Type | Diameter (mm) | Mounting | Glass hole required | Primary use |
|---|---|---|---|---|---|---|
| WF150 Window Fan | Manrose | Axial | 150 | Window glass | Yes — 150mm circular | Bathroom / toilet direct window exhaust |
Brand Equivalents
Window exhaust fan equivalents across brands active in Australian Class 2 strata remediation.
| System type | Manrose |
|---|---|
| Window-mounted exhaust fan (150mm) | WF150 Window Fan |
Glass drilling and airflow compliance
- Window glass must be drilled by a glazier before fan installation — drilling existing glass is a specialist operation, not a trade task
- Toughened safety glass cannot be cut or drilled after manufacture — window must be replaced with pre-drilled glass if toughened
- Airflow from window exhaust must comply with AS 1668.2 — confirm adequacy with mechanical engineer for the specific room volume
Disclaimer
Information is general only. Window exhaust fan selection must be confirmed against window glass thickness, glazing type and the current manufacturer technical data sheet. Fan airflow must comply with AS 1668.2. Do not rely on this reference as a substitute for a mechanical engineer or licensed electrical contractor.