How Whirly Bird Ventilation Works

November 21, 2018 Roof accessories

You might have seen a whirly bird ventilation system in many Australian residential rooftops. It’s this turbine vent that’s shaped like a cylindrical dome. It mainly works to dissipate the heat from the ceiling so that the air that flows around the house is properly ventilated.

Whirly birds have semi-mechanical fins that spin with the wind. As it spins, the whirly bird creates a vacuum that absorbs the heat from the ceiling cavity. It also allows cooler air to enter the roof at the same time.

How efficient are whirly birds?

There are two kinds of whirly birds but one type is significantly more efficient in terms of operation. The passive type is solely dependent on the wind when it spins, and thus, its operational capacity can be limited. The active type, on the other hand, has a mechanism that helps the turbine turn even if the speed of the wind is slow. It’s in constant motion so it can move more hot air out of the house.

The diameter of the whirly bird may also determine its efficiency. Without any question, the larger domes are more capable of removing bigger volumes of air from the house. But then, the size of dome will still depend on the size of your house.

A typical whirly bird may be about 30cm to 35cm in diameter. At this size, the mechanism can effectively turn with a wind speed of 8 to 10km per hour and remove about 10 to 30 cubic metres of warm air per minute.

Why proper ventilation is important

It’s important for any house to have sufficient ventilation so that the air quality is beneficial rather than hazardous. Neglecting this aspect can cause a lot of problems with your family’s health and to the general condition of the house.

For example, the roof’s temperature can get up to 50°C in the summer. If your house does not have a proper ventilation system, then the heat that collects up there has nowhere to go but down the house. Once this happens, the cooling appliances you turn on, such as the electric fan or the air conditioner, will need to exert more pressure to fight off the heat.

In the winter, when the air is damp and there is no proper ventilation, the moisture won’t dry fast enough. It can then seep and soak into the walls and insulation. Thus, you might soon discover moulds and mildew formation around your house or notice paints chipping or peeling off.

Think of all the expenses you have to shell out for sky-high utility bills, wall repainting, and fixing whatever damage that moulds and mildew may cause. But if your roof has a whirly bird, you minimise these expenditures.

Installing the whirly bird

The installation of a whirly bird is relatively cheap and budget-friendly. They work best for apartments and moderately-sized homes hence, and are one of the most affordable and cost-efficient roof accessories to add to your house.

Whirly birds can be fitted to most types of roof surfaces. You can choose the colour of the dome so that it will blend with the roof. You can also maximise the effects of the whirly birds if your roof has no sarking under it. For best results, the operation of the dome may also be combined with other ventilation options or roof cooling systems.

If you’d like to know more about whirly bird ventilation, contact Amazing Roof Restoration for the details. We’d be happy to assist you in making your home properly ventilated and comfortable.

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