Ceiling mounted exhaust fans are a cheap and effective way to remove steam from bathrooms or cooking odours from a kitchen, provided they are done properly.

Without a working exhaust fan in place bathrooms quickly become mouldy and full of condensation and kitchens build up a greasy film on cupboards and surfaces near the hotplates.

The most common problem with exhaust fan installations is a lack of roof space above the fan to disperse the steam.   You need somewhere for the steam to go to.  It’s no good trying to pump hundreds of litres of steamy air into a space where the roof is just a couple of inches above the exhaust fan.

When there is not enough air space or the ceiling is very low above the fan the steam that is extracted condenses on the underside of the roof and drips back down through the fan.

The usual problem areas are flat roofs and lower floors in a multi storey building.

In these cases it may be possible to vent the fan out to the eaves or an outside wall.  This is usually much easier in a new building than an already constructed building.


Regulations now require exhaust fans, Tastics and rangehoods to be vented to outside when installed in a newly constructed building.

If you are simply replacing an existing fitting that is not vented then the replacement usually doesn’t need to be vented.

Venting your exhaust fan is a good idea if it can be done, however some brands of vented fans are quite restricted in their airflow and don’t seem to perform as well as an unvented fan.

The other option is to cut a vent into the roof directly above the fan to direct the steam outside.  These are typically a short tube with a “Chinaman’s Hat” style cap on top.  These vents work well, but there is always a risk of future problems with water leaks whenever you cut a hole in your roof.

In some cases the only option may be a wall or window fan.  Wall and window fans come with their own set of challenges.  Click here to read our article and find out more about the benefits and problems of wall and window mounted exhaust fans.

Contact us for free advice and quotation on your exhaust fan installation.
Phone Mance Electrical on 6331 4711.

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