The turbine ventilator (also known as “whirlybird”) is one of the many types of roof vents available , popular for its use of wind power to draw heat and moisture out of the attic space.
In theory, this sounds wonderful, but in practice, how good is it? Many experts point out the problems of noise when a bearing goes bad, frozen turbine , precipitation leaking in when the turbine isn’t moving , and mainstenance hassles, due to hazards of working on the roof to correct malfunctions.
Thanks to the power of “Web 2.0″ blogs, we can now gain some insight into real world experience in the field. The popular “askthebuilder.com” blog likes turbine vents because the data available shows considerable exhaust power , but his readers seem to find the drawbacks pretty daunting . Here’s a sampling of the comments he received:
“I need to replace my roof wind turbine as it is noisy and wobbling because of wear…”
“I have a turbine vent in my attic – tonight it is making a terrible noise & spinning out of control…”
“My neighbor’s turbine vent has begun to squeak horribly…”
“I have two turbine vents. One stopped working last winter and led to frost build up in the attic and moisture spots on my plaster ceiling. I replaced the vent last fall and I still have frost and moisture in the attic…”
“I have two externally mounted wind turbines. They are old but in good condition. They are stainless steel. One barely turns and the other not at all… I had a water leak into the immobile one during a strong monsoon storm last summer and am sure it leaked only because it was not turning…”
From this response (none of whom raved about how great the vents were), it appears that turbine ventilator maintenance is not so simple after all. turbine vents contain parts that are in constant motion , and when exposed to inclement weather they will eventually break down . Proper installation, though apparently simple enough, can be tricky, and having to climb on a slippery roof to oil some squeaky bearings can be hazardous.
Is there a better alternative?
The Aura Ventilator, manufactured in the USA by Active Ventilation Products Inc. is a competing product with much to recommend it. Like the turbine vent, it too uses wind power to create a vacuum and draw hot air and moisture out of the attic. But the comparison stops there: the Aura Vent has no moving parts.
Using an innovative patented technology, the Aura Ventilator utilizes a principle called the “Venturi Effect.” The Aura Ventilator is cylindrical, with the outer surface consisting of vertical louvers. Inside the vent is another cylinder of louvers, angled in the opposite direction. When wind enters through the outer louvers, it moves between the two sets of louvers and, due to the Venturi effect, produces a vacuum which exhausts the air from the building or attic.
Incidentally, Martin Kolt of Active Ventilation Products challenges the accuracy of the exhaust (cfm) data for turbine vents. The origin and specifics of the data which is usually quoted is undetermined ; Kolt believes the exhaust power is far less than advertised. The cfm data on the Aura Ventilator website is the result of independent testing by Georgia Tech laboratories.
Because there are no moving parts and it is made of 100% recycled rust-proof aluminum, the vents are guaranteed for 5 years. The Aura vent avoids virtually all the problems associated with turbine ventilators, such as noise, maintenance, intrusion by animals and insects, and entrance of moisture through the top of the vent. The AV has louvers that are so small that even insects can’t enter and the shape of the lid is designed to cover the entire roof opening to prevent leakage when there is rain without wind.
The Aura Vent has been tested in sustained winds up to 200 mph with no rain leakage (a recent testimonial on the site confirms that they survived two hurricanes in the West Indies with no leakage ). In contrast, turbine ventilators are known to blow off the roof at high wind speeds; hurricane preparation guidelines require them to be removed and capped in advance of a major storm.
Aura Vents are inexpensive, easy to install, and range in size from 4″ to a massive 72″ in inside diameter, big enough to ventilate the largest commercial buildings. They even offer a retro-fit kit to replace your old turbine with a new Aura model.
Based on the disadvantages of the turbine vent noted above, the Aura Vent is definitely worth investigating as a worthwhile alternative in wind-powered ventilation .
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