Ok I’m probably opening up a can of worms but I want to install one of these fans in my roof. These are the dome shaped fans I’m talking about. My attic is really big, it goes from one end of the house to the other (45′) and is as wide as the house(25′) The pitch of my roof is 10/12. I can walk around up there no problem, the collar ties just clear my head. Unfortunately it gets to be 10000 degrees up there so I figured one of these fans would help. I have soffit vents, a ridge vent, and 2 gable vents now. If I put one of these fans in do I have to close up the gable vents and the ridge vents? I don’t want to pull more hot air in……….Any input is appreciated.
CRaig
Replies
Don't do it!
You'll likely lower the attic pressure relative to the house, and suck your hard-earned conditioned air up through electric boxes and top plate penetrations.
So the attic's hot - so what?
Forrest
Do you plan on finishing the attic or otherwise spending much time up there? If not, attics get hot, no big deal.
If you do have good reason to cool it down, proper insulation in the rafters will do wonders. Just have to make sure to keep that airway open from the sofit vents to the ridge vent.
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I'd try covering the inside of the gable vents and see if that helps - measure temp differences in/out before and after the cover up. Gable vents and ridge vents are not supposed to be installed on the same roof. Your present configuration is probably only ventilating the upper 1/4 or so of the attic.
I agree w/Matt. Make sure your soffitt and ridge vents are not blocked and then close off the gable vents. If that isn't sufficient and you really need to dump the hot air quickly, a thermostatically controlled gable vent might be all that you need. Much less expensive to install.
The reason I wanted to do this was because the upstairs bedrooms, bathroom, and hallway is so hot. I figured by lowering the temp. in the attic it would lower the temp of the living space below. Everybody tells me it worked wonders in their house. I figured the fan would help pull cooler air upstairs so as to keep the living spalce cooler, and not have to rely on air conditioners as much. I don't have central air I have wall units. What gives?
craig
>I figured the fan would help pull cooler air upstairs so as to keep the living spalce cooler, and not have to rely on air conditioners as much. I don't have central air I have wall units. What gives?<It's probably cooler in their attics because, cooled living space air is getting sucked into the attic in "everybody's" house. If you've already got that much venting, another vent is not going to make much if any difference and it's going to use quite a bit of electricity not doing much of anything. Add some more insulation. If it's 95d outside, then the coolest it's gonna be in the attic is 95d with the best venting disregarding any radiant heat gain. You need to put a barrier between you and the attic temp.http://grantlogan.net
Who got Bo Diddley's money?
What gives?
The gable vents are defeating the purpose of the sofit vents.
It's easy enough to test this theory. Just staple some plastic over the outside of the gable vents and see what happens. I say the outside because air is being drawn into them. If you do it from the inside the air will just find it's way in the edges. Optionally, you could do it from the inside and tape it real well with duct tape, so the air doesn't come in around the edges.
Anyway, seal up those gable vents and see what happens. I bet the upstairs rooms become a lot cooler. Worst case scenario, it doesn't cost much to prove me wrong. :)
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Edited 6/17/2008 8:28 pm by Ted W.
Yes, this IS a good idea. You didn't mention what part of the country you are in, but most attic temps are 140+ on a typical summer day... and yes my upstairs is warm...even with 16" of blown pink insulation in the attic. I purchased mine at HD for about $65 and is thematically controlled and turns on @ 105*. My electric bill, aka, my AC bill, lowered by $25 per month...not a bad ROI. Since you say you have sofit and gable vents, you will not likely be sucking conditioned air unless you leave your attic access open.
I live on Long Island, New York. I have plenty of insulation in the floor, and all penetrations for pipes, and wires have been sealed with fire caulking
<I purchased mine at HD for about $65 and is thematically controlled >
Don't know you, but have to giggle at the idea of a "thematically-controlled" fan. I wonder would different themes would result in what different speeds and perhaps directions.
Big ;-)
Forrest
I don't think pink insulation is blown into attics, just placed there.. and probably not perfectly..
What about in an attic that has no ventilation? I have a walk up attic in an older house (1895). There are two double hung windows that I replaced a few years ago, but I'm not going to go up there and open them every day that it gets hot and close them every time there is a chance of rain. It has very little vermiculite insulation under the T&G flooring, and about 10-12 inches of fiberglass insulation everywhere where there is no flooring (Where the roof meets the floor and about 2' in from there) the pitch on the roof is 12/12 and the roof was replaced about 5 years ago. The house itself doesn't have any insulation in the walls except for where I have torn walls out. Infact the one side of the house where the stairs are is completely un-insulated. I know that everyone is going to say insulate it better, but thats not happening. I'm not drilling holes in the plaster to insulate from the inside, and the asbestos siding on the outside is not coming off either. I put the central air in about 4 years ago, and it works decent at cooling the upstairs, but I think it could be better. Would ventilating my attic be of any assistance?
no takers on this one?