attic cooling question

Old 04-02-03, 07:58 PM
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attic cooling question

I live in Dallas, TX where the heat is really high (100+) many days throughout the summer. I have had several companies provide bids to install additional soffit vents, as well as installation of radiant barrier, both blown and in rolls.

Q1: Does radiant barrier work?
Q2: Which is more effective, blown or rolled(film)?
Q3: What is a reasonable price for radiat shield?
Q4: Any estimates on the sq. ftg of soffit vents I need, assuming 2800 sq. ft of roof?

I have checked out ridge vents but I have several hips and the appearance would be rather poor...
Old 04-03-03, 12:15 PM
Ed Imeduc's Avatar
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Id forget about the RB there now. I would make sure that vents
in the soffit will work and let air up into the attic. Then have them put in a good roof vent fan on a tstat. if its blocked off in the attic put two of them in.This could be on the back side of the home near the ridge.In some of the good books they say a 1/6 hp will do 2600 sq ft of attic. The way we look at it a good vent fan on a tstat in the attic is like a 1/2 ton of AC. The Gov. said in tests that the RB get dust on it and dont do any good after a few years
I find also that with the ridge vent it just dont let enough air out ED
Old 04-04-03, 06:12 PM
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Hot attic

Ed and I agree on some and disagree on some of this, but that's OK, the more opinions, the closer we come to "TRUTH".

Make sure you have sufficient soffit vents, if air isn't coming in, anything you do to try to vent it out is not going to be effective. If you ever owned a 60s or 70s Volkswagen Beetle (kind of airtight) you know what I meant.

I can't understand how "spending" electricity, on a fan, can save electricity by keeping heat out of the attic and thereby the house.

I've only ever done a few hip roof houses, and I used AIR HAWKS, they look like a hood scoop for cars. I think that I have seen "hip vents" that act like ridge vents but don't it's been 7 or so years since I researched anything for a hip roof.

I've found that the radiant barrier paint, while expensive, is effective, it's applied (usually sprayed) on the underside of the roof decking. Dust can't land on it to decrease effectiveness.

More important than keeping your attic cool, is keeping that heat out of your house, I think R30 or more is standard now down here.

I'm a big believer in doing as much as I can passively. I hate the power companies, and I know that there is a finite amount of fossil fuels. I've gone so far as vent skinning, fluorescent lights etc, etc. But we've got 2200 square feet and our bills are about $50 per month. No fans in my attic.
Old 04-11-03, 11:18 AM
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Lightbulb Passive venting

I also strongly suggest passive venting whenver possible
I have 2 turbine type roof vents on my 900 sq ft house and attic temps rarely exceed 120.
Of course Oklahoma has plenty of wind to drive the vents and I have a light colored roof which always helps.
2 people living in the house, $85.00 (995 Kwh's) is our highest bill in a 80 year old house with NO insulation in walls or floor and 3"-4" in the attic (attic is on the list to get fixed)
Winter electric bill about $30 (300 KWH's) average.

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