I'm getting ready to have a new roof installed (tear-off old and replace),
and had a question. Right now my roof does not have ridge vents, it does
however have several passive vents ("turtle" vents?), plus one atfic fan
with a thermostat. The soffets are vented also.
Should ridge vents be included in the new roof?
The ridge vent should not be used with other roof mounted or gable end
vents. They can disrupt the air flow through the attic. A properly setup
ridge/soffit vent system does not need to have power roof vents to help move
hot air out of the attic. Whole house fans work great with a ridge/soffit
vent system. We do not consider them the same thing as the power roof
How do I figure how much ridge vent I need to use?
Take the square footage of house under roof X .48 divide this number by 20
(for V-600 products), by 17 (for V-400E or X-5) or by 13.5 (for V-300 or
Fold-A-Vent products) this will give the lineal feet of product needed to
meet a 1/150 vent ratio. If you are only going for a 1/300 (code minimum)
vent ratio divide the above result by two. REMEMBER there MUST be an equal
amount of soffit vent (in NFVA) to balance the ridge vent.
Hope that helps
I go into a lot of attics. The ones that rely solely on ridge vents for air
flow are always the hottest. I think that they are good to have for a
minimal amount of air flow, but I would keep the other vents and attic fan
as well to help bring the temperature down. Also good and many soffit vents
On Aug 7, 9:15 pm, email@example.com wrote:
There are two very different opinions on this and I've yet to see any
actual study that shows which idea is right.
1 - The more ventilation you have, especially static vents, the
better. The idea here is that hot air rises and will make it's way
from the soffits out any top vents, be they ridge, gable, can vents,
etc. So, if you have a gable or other static vent, leave it in place
when adding the ridge vent.
2 - Having a ridge vent, with a gable, can vent, etc will shortcircuit
the air flow, with air coming in the gable, out the ridge, without
properly cooling the attic,
I tend to believe in 1 myself. With a power vent placed close to
another vent, like a gable though, I could see some short circuiting
going on there, making the power vent not worth it.
If anyone has seen any actual test data, it would be interesting,
I find it hard to believe that SO much hot air will rise on its own to
the ridge vent that the attic will be cool. A fan mounted close to
the peak can only move more air.
Doesnt seem like there should be controversy over it. Getting a new
roof is expensive but how much will adding a ridge vent and and attic
fan cost? Not much
On Aug 7, 11:19 pm, firstname.lastname@example.org wrote:
Cost of electricity? A few dollars per YEAR? Big deal!! Air
conditioning being sucked out- If air was being sucked out the attic
wouldn't be so hot would it. In a dead air space such as above roof
in a finished attic how much air can possibly be sucked out? Fans are
a must for anyone living in an area subject to high heat.
Maybe you exaggerate. What if fan runs as directed by t-stat? And
avoids roasting (literally the past situation in my house) roofing and
Not to mention keeping things substantially cooler at peak temps
ceiling of floor below. Resulting in noticeably lower afternoon temp
on August afternoons. I'll take that any day.
A cheap and simple seal around door to attic, and your second phobia
Not to mention that the floor immediately below is "conditioned" by
opened to ambient at night with small fan assist.
have had several jobs with plenty of ridge vent and soffit vents still
to hot . i put in next larger size power vent(s) than needed along with
ridge vent and attic and inside home then stayed cooler in summer. lucas
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