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Environmental ventilation


Heat trapped between the underside of the roof and the insulation dramatically reduces the effectiveness of the insulation and the cooling qualities of the roof space. The air pocket that is the roof space is in itself an insulatory trap, but once it is overheated it acts in reverse and can cause the dwelling to heat up, reaching temperatures of up to 70 °C during the summer months.

Unpowered Whirligigs (right)

The simplest and most cost effective way of dissipating heat from the roof cavity is the installation of mechanical whirligigs which are powered by air flow or the wind.
These simple fans (pictured) suck out the heat from the roof space. The whirligigs will handle up to 50m2 depending on the pitch of the roof, so often modern houses will require more than one to effectively remove the heat from the roof.

Powered (right)

The more effective (and dearer) method of removing heat from the roof space is via electric powered fans which suck air out of the roof space. Operating via a thermostat which regulates the fan or fans to turn on and off once a given temperature has been reached, these fans will cope with up to 100m2 each. Passive eave vents need to be installed to create a cross flow of air and airchanges.

For large roof voids, we recommend ducted systems using a powered fan (right) which is ducted to all areas of the roof void and then exhausted from the roof eaves, gables or directly through the roof.

They are controlled or switched by either timers or hygrometers (humidity levels) and are set to operate to suit. They can be altered in terms of both the time they run for and when they run.

Solar Powered Fans (right)

These Australian made low profile solar powered vents are far more powerful than whirlygigs and each fan will provide enough air movements to achieve five air changes per hour for 100m2. Passive eave vents need to be installed to create a cross flow of air and airchanges.