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Roofing/Roof Vents and Whirlybirds


A year ago the roof was replaced.  Two whirlybirds were removed and roof vents put in.  The house has been MUCH hotter.  It has been suggested that two whirlybirds be put back.  What are the pros and cons of having both whirlybirds and roof vents?

Thanks for any advice.

Hi Janet,

Functionally, whirlybirds work great. The more attic venting, the better. Aesthetically, they stand over the top of your ridge. Maybe not the best thing. You need to decide which is more important to you personally.

Attic environment Options:

Solar Powered Electric: No monthly electricity usage costs but they don't seem to last long before you have to replace them.

Hard Wired Electric: If you set the thermostat only when needed, the electricity usage is reasonable and they last a long time, 15 years or so.

Ridge Vents: With either composition or tile, a ridge vent system can be constructed. This can be a good system combined with the other options but either way I do like to incorporate the use of a fan to help air movement.

With any of these options, it's important to have an equal number of square inches of passive venting.

Quantity and Placement:
Calculate your attic floor space. Using the 300/1 ratio, you need 1sq foot of venting for every 300sq feet of attic floor space. Placement should be 50% near the ridge and 50% near the lower areas. Most people don't like to put vents on the front side but better distribution means better cooling.

If you have a cathedral ceiling venting is much more complicated but can be engineered.
Also proper insulation is very important.

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Joe Ronstadt SR


All questions related to residential roofing and roof repair.


In Business Since 1980, over 34 years as of 2014. Specializing in residential re-roofing and roof repairs.

OC Register and San Clemente Journal.

relevant construction credentials are: Licensed Contractor since 1980 by the C.S.L.B. 390685 - roofing 452151 - general, frameing, painting, concrete special coatings.

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