Imagine a boiling pot of water with a lid on it for a minute. As the pot gets hotter, hot air continues to build up and make the water boil faster. The moment you take the lid off, the hot air is able to escape and the water calms down. This is EXACTLY the same function as a whirlybird.
How Whirlybirds Keep Your Home Cool
Just like lifting the lid on a boiling pot of water, whirlybirds allow hot air to escape out of the roof space. As the roof heats up during the day, this heat becomes trapped inside the home. Without anywhere to escape, this heat radiates downwards into your home. Therefore, a whirlybird extracts the heat from your roof space, which in the peak of the Perth summer can reduce temperatures 8 to 12 degrees in the roof space.
How Whirlybirds Prevent Mould / Mildew
Without sufficient ventilation, just like the hot air trapped in your roof, moisture gets trapped in the roof space. This moisture builds up over time, coming through eaves, from inside the home, through the roof etc etc. If it continues to build, the moisture promotes the growth of mould and mildew. With sufficient whirlybird ventilation, as the roof heats up during the day, moisture is allowed to evaporate and escape the roof.
Types of Whirlybirds
There are three main types of whirlybirds; wind-driven mechanical, electric and solar.
Wind-Driven Mechanical Whirlybirds (Windmaster, SupaVent, TurboBeam)
- Wind-driven (no electricity or solar panels)
- Cheapest form of ventilation
- Most homes require multiple for sufficient ventilation
Solar Whirlybirds (Maestro, Acol)
- Driven by solar panel either fixed to unit or alongside
- More efficient than wind-driven
- Don’t extract heat in the evening due to lack of sun
Electric Whirlybirds (Aeromatic, Maestro)
- Most efficient ventilation system
- Temperature-controlled using thermostat
- Electrician required to install
How Many Whirlybirds Does Your Home Need?
A general rule for wind-driven whirlybirds is 1 per every 50 – 80m2 of roof space. However, factors like roof pitch, roof design and colour of roof need to be factored in. Using Google Earth and our tailored ventilation software, we can calculate a ventilation solution tailored to your home.