Whirlybird Guide – Roof Ventilators and Whirlybirds in Your Home
A guide for the curious consumer interested in Roof Ventilation & WhirlybirdsWithout a proper means of insulation or ventilation, a standard roof space quite simply traps & accumulates heat as the sun beats down onto your roof. This heat radiates down through your ceiling, will warm your home, and accounts for around 25% to 35% of the heat gain in summer, right next to windows. Obviously, you can install blinds to block heat out of windows, but you can’t put blinds over your roof. When roof heat starts seeping through your ceiling, your home becomes stuffy and hot. Most homeowners will resort to using air conditioning, though unventilated roof spaces will continue to transfer heat. Without a means to keep your home cooler for longer, your power & utility bills can skyrocket. Methods to ventilate your roof have changed drastically over the past couple of decades. The product most readers are familiar with is the roof whirlybird. One of the first designs for the whirlybird was patented in 1910 by Samuel Ewart. This design in principle hasn’t changed in decades, as it still relies on wind to make the turbine spin. They may also rely on the expansion of air in your roof cavity from rising temperatures.
Whirlybird Mechanics – How do they Work?
“Over the last five years I have had two whirlybird units from Bunnings in my ceilings and had, so I thought, done a good job. I later did extensive research and was determined to find an alternative to the whirlybird … The Solar Whiz has now been in for about six months and the temperature difference we have noticed is amazing! On hot days the temperature is about seven degrees cooler upstairs and dramatically cooler downstairs. If I close all the openings in the house and open one window down stairs, I can feel the air being pulled through the window and up the stairs to the top floor.” Greg Savill (Sydney)There’s typically two types of whirlybirds: your mechanical, active-powered whirlybird, and the conventional wind-driven whirlybird. The far more popular conventional whirlybird operates when wind hits the turbine fins, causing the vent to rotate. The motion creates a vacuum that sucks air out of the roof space. Unfortunately, a single whirlybird will not usually suffice for a modern home, and may require up to four or six units to be installed to feel an effect! It is worth noting however that they can assist in reducing heat build-up as well as humidity while enhancing air movement in your home. The design is also typically able to resist rain, though it isn’t impervious.
Whirly Bird Cooling and Rate of Airflow – Are they Effective?whirly bird models versus other dedicated ventilators here! In order to feel the effects of ventilation in your home, you might need around 700 m³/h of air flow to keep your roof space near to the ambient temperature outside. Of course, this means you’ll need more than one whirlybird to do the job.
Whirly Bird Cost & Affordability – Is the Expense Worth it?A standard whirly bird isn’t terribly expensive. You can pick one up from major hardware stores for as cheap as $60.00 AUD, and sometimes their installation can be done DIY. However, affordability often comes with a compromise in the modern market, as cheaply built whirly birds can present design flaws after installation. Below is a list of downsides that come with purchasing wind-driven whirly bird turbines for roof ventilation:
1) Reliant on AirflowA whirlybird depends on wind to spin the turbine. Quite simply, if there is no wind, it doesn’t spin properly. On an especially windy day a whirly bird might ventilate your roof to a degree. However, those dry (or humid) summer days when there is no wind will prove the whirly bird inefficient as your roof space bakes under the sun. In locations where strong winds are common such as valleys, a whirly bird performs as expected. Otherwise, it simply isn’t advised. A powered, mechanical whirly bird might help, but their price & running costs have proven to be unattractive to the public.
2) Prone to Running NoisilyCheap roof whirlybirds aren’t necessarily made to run efficiently, or quietly. As the whirly bird operates, the parts rub and can make low squeaking, or grinding noises. The stronger the wind, the more obvious the noise. On top of this, without regular lubrication, the whirly bird bearings can wear or loosen. Worse still, they can make the whirly bird run louder if said bearings are damaged.
3) Inefficient DesignAs explained, roof whirlybirds are inexpensive, though inefficient in moving air through your roof space in comparison to other ventilators. Simply, single roof whirlybirds won’t be enough to ventilate your roofspace, and reduce ambient temperature in your home. It would take at least fifteen to twenty residential roof whirlybirds to effectively cool the average-sized Australian home. This many whirlybirds is not only expensive, but ruins the look of the home, as well as makes installation cumbersome & costly.
4) Inclined to Malfunction or DetereorateWhirly birds are usually resistant to rain, though their open design can easily catch leaves, dust, or other foreign objects. If enough of this debris enters the whirly bird turbine, it can interfere—and impact the whirlybird performance. Cheaper whirly birds may also rust or can be damaged by severe weather. With maintenance & cleaning, this can be avoided—but are you willing to regularly maintain the fifteen to twenty residental roof whirlybirds needed to keep your home cool?
Solar Whiz – Your Solution for Roof VentilationThe Solar Whiz is a dedicated self-sufficient solar powered roof ventilator. Quite simply, it provides you with the efficiency of a powered roof whirlybird without the expensive upkeep or power bills. Given that the Australian climate features near-constant sun exposure when it’s hot, the Solar Whiz runs efficiently throughout the day. It even operates on overcast or rainy days!
What about Ventilation for Commercial Properties?commercial ventilation line! We’ve designed them to properly ventilate the extreme heat that large-scale properties can produce. On top of that, our commercial exhaust fans are excellent at adequately ventilating fumes for industrial businesses. Our solar commercial ventilators come in two sizes:
the SW-RAF7000, capable of moving 7,000 m³/h, and the SW-RAF10000, capable of moving a whopping 10,000 m³/h! If you’re thinking of buying cheap whirlybirds to help ventilate your business, consider a Solar Whiz instead! You’ll be feeling the difference during those hot summer days.