Today, we will be looking at the arguments for and against solar powered roof ventilators and whirlybirds.
The strongest argument for Whirlybirds is that they are cheap to purchase. However, they also need to be installed. Domestic whirlybirds are generally quite simple to install, but if you can’t do it yourself – the cost of getting them installed by a certified roofing plumber will normally be several times the cost of the whirlybird roof ventilator itself. Even Airtasker (when I checked) starts at $100 and goes above $250 for installation.
Solar roof fans are more expensive, but as mentioned in part 1, they are 10-30 times more effective – so for most homes – you only need 1 unit for the whole house (unless you have separate roof spaces).
To move enough air to make a difference to the temperature in the roof space in the average Australian home – at an airflow capacity of approx 100 cbm/h per unit – anything less than 10 whirlybirds for a house is unlikely to make a noticeable difference to either the roof space temperature or the amount of heat radiating through the ceiling into the house.
If you look at the cost of purchasing 10 whirlybirds (whirlygig) vs one solar-powered roof ventilator – the numbers don’t stack up very favourably for the whirlybirds – especially not if you have to pay to install them. The solar-powered roof ventilators are far more valuable if you need power and want to make a serious difference to the airflow changes within your home or business.
If you’re still interested in finding out more about “Do Whirlybirds Work?” then you can find a number of useful websites online. I would excercise caution if the site belongs to a ventillation company that is trying to sell you their product.