Do "whirlybird" roof vents work?

[donewithcity]

We are putting a new roof on a 2100 sq ft double wide. Instead of static vents I am installing 14" turbine attic vents. I am putting in 4 so far, 3 over one side of the gable on the main house and one for the attatched shop. Looks like the other half of this building's gable attic is not connected to what I have vented. The big question: Should I install a couple more on the other side of the roof or just put back in the little roof vents that come with a pre-fab?
I would post this in shop, alternitive energy, etc, but think I can get more feedback here.

[The Paw]

The whirlybirds work great, the only problem i had was that the wind speeds here get so high on occasion that the internal struts came apart under the force. If you have any kind of shelterbelt, that should not normally be the case.

It sounds like you are putting in a lot of them, you should be able to find out proper sizing somewhere.

The other thing is that they are only truly effective when you have the soffit vents clear and properly sized. That allows the turbine to draw the air from the eaves and exhaust it near the peak.

[T-Bone 369]

Originally Posted by The Paw

The other thing is that they are only truly effective when you have the soffit vents clear and properly sized. That allows the turbine to draw the air from the eaves and exhaust it near the peak.

This is the best advice for any roof venting job. We have installed whirlies on a couple of roofing jobs at the homeowner's request but usually just put in the pot vents. If the eves are open to let air in and the pots open near the top to let air out the natural convection creates draw - no need for mechanical assistance. Besides, every house I have been in with a whirly more than a couple years old squeeks.

[Sawmill Jim]

And if the roof is very flat they leak We just put a new red metal roof on our house only one hole in the new roof ,for the electric . Every device on a roof is a future leak waiting to happen

[KIT.S]

We had yellowjacket wasps move into ours. Pretty exciting when you are on the roof and find out! Amazing how fast you can get down a ladder. We sprayed them, but they came back again the next year.
Kit

[Harry Chickpea]

Only had a problem with one of ours in Florida when a hurricane came through and tossed the turbine on the ground. Never any squeeks, if you really really listened hard, you might hear a slight thrumming in a strong wind.

The turbine is more to allow a free flow of air out and to keep windblown rain out than to provide suction. I far prefer the passive turbine to a power vent. I've seen a couple of those burn up. If someone hadn't been around those house would have burned to the ground.

[RonM]

I would just go for vented ridge caps and be done....

[Alice In TX/MO]

Ridge vents are MUCH more effective, less vulnerable to wind and deterioration, and don't wear out and go SQUEEK SQUEEK SQUEEK at 2:00 AM in the morning.

[Twp.Tom]

Ridgevent has as much air displacement per linear foot as one standard convertible vent. In order for the shingle or roof material to meet manufacturers specs for ventilation you normally need one vent,or one linear foot, per 100 sq.'.Not sure about turbines,you may want to find out what they are rated for.

[Ohiogal]

I had turbines on my house, then Hurricane Ike came through as a Cat 1. Trashed them, to the point where the tops flew off leaving a 12" hole in the roof of my house. I was saved by the fact that Ike for us in SW Ohio was a huge wind storm - no rain. Otherwise I'd have had a major mess/flooding in my upstairs from the holes in the roof! I had to have my neighbor climb up there and put a 5 gallon bucket over the holes, and fasten it down with screws. I had them replaced with the box vents.
On the ridgecaps, my roofer will NOT use them. Said they plug up with dirt/debris in a few short years, rendering them useless. I tend to agree with him on that, I have a steel roof on my barn, and you would not believe the carp that comes in under the ridge cap on that building. He said the only time they use them is if the roof has no attic area - otherwise they use the standard box vents.
And power vents? Forget them too - if a fire occurs, the thermostat snaps on and vents the flames. The newer models may have an override on them, but the damage is going to be done and quickly as its like creating a chimney out of your house if fire breaks out.

[Harry Chickpea]

I also agree that ridge vents are not the be all / end all of vents. In a storm with strong winds, like a hurricane, rain can easily be driven up into them. After learning about turbines flying off in hurricanes, I found that there are caps you are supposed to put on to replace the whirly. Three or four screws is all that holds them on.

Another issue with vents, found by researchers in Florida looking at hurricane damage, is that within most wind events, a structure that is entirely sealed will do better than one that is heavily vented. There really is no one good answer.

Passive turtle top vents and wind turbines are my top choices. I would never ever ever have a power vent. The whole concept is absolutely foolish. With proper ceiling insulation, the cost of operating a power vent is greater than the savings to the AC bill.