Whirly bird – Continuing on from our handbook from Part 1.
In this section we want to get into the ‘nitty gritty’ of exactly what the whirly bird can really do and if it’s still an alternative which should be seriously considered when ventilating your house. As times have changed we have seen that there are a variety of whirly bird alternatives out there (and we feature them all on this blog), however it’s a fact that the whirly bird is still the most popular. Similarly to myth busters we’re going to stack up the facts, queries and reasoning behind the well known whirly bird.
Does the Whirly bird work at night?
The whirly bird works all day everyday…if there’s enough wind to keep it going that is – or the air in the roof space is expanding – i.e. getting warmer. So if there’s a breeze in the air and the wind is blowing it’ll be working. In saying that, you need to ask yourself some more questions. Do you want it to work throughout the night in cold weather? If it’s a sticky hot summer’s evening and there’s no breeze, you shouldn’t expect any difference in your roof temperature. Night operation is an option on many other roof ventilation alternatives so when you make your purchasing decision, consider how effective it’ll be throughout the day – but keep in mind that the evenings can remain over 30 degrees during the course of summer, so you’ll want something working hard for you day and night.
What about the cost of installation of a Whirly bird?
The cost and time of installing a Whirly bird is going to be generally quite similar to installing any other roof ventilation alternative. However, make sure you remember that you will have to fork out some extra cash to install any roof ventilation product you buy, whether that be a whirly bird, solar ventilation unit or mains powered extraction fan. When you install a whirly bird it’s generally a bit more expensive to install it on a two story home than it would be for a one story home.
Referring back to Part 1 of our article, you’ll need at least 8-10 whirly birds on your roof to notice any considerable difference in the roof space temperature. So make sure you’re prepared to pay for the installation of this amount of units. In contrast if you go for a higher air flow volume alternative like solar ventilation or a powered roof vent, it’ll be the installation of just one or two units which will decrease your installation costs significantly (also keep in mind how many whirly birds you want stuck up there on your roof which may effect the good looks of your house).
What is the Whirly bird made out of?
Each type of material has its pros and cons. Depending on the size and shape of the whirly bird it’ll effect the unit’s effectiveness, durability, weight and how easy it is to install on a roof.
Where on a roof should you place a Whirly bird?
A whirly bird should be placed at the highest point of the roof – this is where it will receive the most rising heat and wind to power it throughout its use. The only issue you need to keep in mind is when you’re looking at installing 8-10 of these units, you’ll struggle to have them all at the highest point of your roof. Therefore as you have more and more units up there on your roof they’ll become less effective as you move them down because you run out of room!
That’s all for Part 2 on whirly birds! If you’re after more information you can read our Part 1 of the hand book or alternatively check out our thoughts on Whirly birds vs Solar Ventilation. Part 3 to follow in the coming weeks!