Attic ventilation Question??


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Old 07-20-08, 08:33 AM
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Attic ventilation Question??

Hello, I have a pretty big attic that gets to be about 160 degree's or so. Especially now since it about 90 out and really humid. I have vents on both gable ends and a ridge vent. My question is, if I put a fan up there that blows out one of the gable ends and as the air circulates will that make a big difference in lowering the temp up there and in return making my 2nd floor easier to cool?? I had central air last yr, but the compressor went or something like that and its a unit from the 70's or so, and they don't make the part I was told. So right now I have 2 window air conditioners up stairs and 1 big one downstairs. Any advice would be great.
Thanks
 
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Old 07-20-08, 10:21 AM
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Absolutely. The natural movement of air should reduce the heat, but a little help from a thermostatically controlled gable mounted fan would move more air and make it at least temperate in the upper part.
 
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Old 07-20-08, 11:47 AM
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diy
Any way to put soffit venting in as well? If yer house is anything like mine, the gable vent isn't that far below the ridge. Thats not conducive to good flow.

Better to bring the outside air in as low on the roof as possible, and let it flow up, to remove as much as possible.
 
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Old 07-20-08, 01:05 PM
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What about putting the fan in front of the windows that are conveniently about 15 inches below the gable vents??! I know leaving the window open will let bee's in but what if I build a frame and put a screen up?? Will this work??
 
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Old 07-21-08, 01:55 PM
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I totally agree with Gunguy on the soffit venting. The cooler air must come from below to displace the hotter air near the peak. Leaving the window open will only let in rain when you forget to close it.
 
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Old 07-21-08, 07:42 PM
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Well the soffit vent is impossible b/c I have open rafters on the outside overhang on the roof. The soffit will get installed when I have siding put on my house which won't be for another couple yrs.
I would love to put a room up there. Its a big enough area for atleast a 8X10 or 8X12. My wife would love to move our bedroom up there, but I am not sure I would like that. It would take away from the storage.
So your saying if I took a fan and placed it in the stairway and blew the cool air from the 2nd floor up into the attic it would take care of it?? I am not going to do that b/c I would be spending more money in elec for the a/c to be running.
Well thanks for the info!! I appreciate it.
Chris
 
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Old 07-22-08, 07:47 AM
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DIY I have the same issues here on my house. Soffit is open, and I have stucco exterior, so soffit venting isn't in my future either. I don't think anyone meant for you to blow conditioned interior air into the attic.

Looks like the fan may be your (and my) best options. Just be prepared to replace the motor every few years, though I had one that ran fine for over 10 yrs in the last house. Of course it wouldn't run that much in VA, here in AZ it'll prob run all day for 9 months of the year.
 
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Old 07-23-08, 09:41 PM
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May I suggest that you install one or two (depending on the area to vent) turbine fans on the roof. These are very effective, reliable, quiet and do not require wiring. They run about $40-$60 for a 14" galvanized or painted model. They are also easy to install. This solution worked wonders in my brothers house. If you don't want to install them yourself any roofing contractor can handle the job.
Chandler is correct regarding the soffit vents. Gable vents are not very effective.
Thanks for listening.
 
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Old 07-24-08, 10:40 AM
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Oh ok! That is a good idea. They are silver and have grooves in them and spin freely right?? I think I know what you mean. I will look into that. Now what about in the winter.? What do I do w/ the fan then?
I have about 10 inches or so of cellulose in my attic between the joists under the tung-grooved floor and my ceilings on the 2nd floor are still warmer than the room itself, especially in the rooms where I have the a/c units which is my computer room which gets the west winds/sun/weather and in our bedroom.
Thanks again for the great advice.
 
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Old 07-29-08, 07:58 PM
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how to know if ventilation is ok?

Our 2nd floor (1925 Cape) has 2 bedrooms and is tough to cool in the summer. The crawl space is very hot and I wonder if they are not well ventilated. Newer siding includes occasional ventilated soffits, but the plywood floor in the crawlspace extends right to the roof and my sense is that the joists below the floor is fully insulated with bats.

Any way to know if ventilation is sufficient? (pressure test? temperature differential?)

Many thanks
Patrick
 
 

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