08-02-11, 09:17 AM | #11 |
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Did the OP abandon his thread?
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08-02-11, 09:27 AM | #12 |
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Hes not the most frequent poster. He'll come around I'm sure.
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09-18-11, 02:42 PM | #13 | |
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Quote:
I would second the radiant barrier suggestion and keeping the thermostat at 84 while out and down to the desired temp by the time You get home. Don't bother with regular insulation. It will just give off stored heat when You least want it. You want a radiant barrier in the attic. Maybe some regular insulation on top of it to keep dust away so as to limit the reflective barrier efficiency. Possibly coolseal or other white reflecting roof covering for the roof if You have dark shingles/black tar up there. |
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09-18-11, 07:56 PM | #14 | |
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Quote:
A radiant barrier should be on the underside of the roof decking. Either painted on or a foil that is already glued to the roof decking, I have the latter. I have seen the rolls of radiant barrier that you staple to the trusses or lay on top of the insulation in the attic. But either way I have always read that you do not want to have insulation over the radiant barrier. |
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09-18-11, 10:28 PM | #15 |
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That's backwards to my understanding as well.
I've always seen shingles/metal/... - radiant - roof decking - trusses - air gap - insulation - ceiling or shingles/metal/... - roof decking - trusses - radiant - air gap - insulation - ceiling |
09-18-11, 11:12 PM | #16 |
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I've never heard it from anyone either. I'm just saying having something on top of the radiant barrier to collect the dust will prolong the effectiveness of the barrier, not sure if it will help insulation much. Otherwise You will be changing the radiant barrier or flipping it on the other side once it collects dust. Maybe cheap air filter material instead?
They do make "radiant barrier chips" which will stay effective even when the top is covered with dust cause You have multiple layers of the stuff, though they are more expensive. |
09-25-11, 07:01 PM | #17 |
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Sorry, but it isn't the easiest thing for me to remember to check in all the time... Anyhow an interesting development. The fan that I was using to circulate the air broke . So I figured I would go without for a bit and see what happens.
Now to preface this I still left the opening to my attic through the garage open and my garage door it vented at the bottom. With that said, there has been no change in my attic temperature. Now some of that can be due to the fact that the hottest summer days are behind us now, but I am also questioning the effectiveness of a fan to circulate the air. Now I am contemplating an all out solar extractor for the roof, I finally saw a company who is rated for the hurricane code in S. Florida. Otherwise I was going to invest in one of those extractors that pulls air from the garage and dumps it into the attic forcing a larger volume of air out through the vents along the lower roof line. SO TTFN while I continue with my new fish tank in the other thread ..lol |
09-26-11, 01:00 PM | #18 |
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So there is an access panel in the garage to the attic? If so I would get a box fan and build a frame around it so it will force air in. Definitively get a programmable t-stat and test it on the per set points and adjust it from there the Honeywell unit I have even has a setting that will let you select how quickly you want the house to cool when it reaches the new set point.
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09-26-11, 08:45 PM | #19 |
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As long as I had a radiant barrier on the floor of the attic I wouldn't concern myself much with temperature and, as far as ventilation, would just make sure that I have enough bottom vents (soffits/eves) and top vent(s) (Wind turbine Roof Fan) for proper airflow. And I mean TOP vent(s) for proper airflow, not middle.
The attic temp would actually be higher because the radiant barrier would block so much heat back into the attic, but below the barrier and the inside would BE and, more importantly, FEEL much cooler because 5% of HEAT is transferred through conduction, 20% through convection, but 75% through RADIATION Unlike radiant barrier regular insulation does not block heat. The R value of regular insulation rates resistance to CONDUCTIVE heat transfer and is not applicable to a radiant barrier. Without a radiant barrier, by the time You are back from work, a lot of is absorbed and STORED in Your insulation and is ready for You to FEEL it's RADIANT glow even though Your thermostat is trying to convince You that the AIR TEMPERATURE is "comfortable". (Unless You have a thermostat that measures "mean radiant temperature" or a "globe thermometer") BTW, apparently It is OK to put a radiant barrier on top of existing insulation AS LONG AS IT IS NOT A VAPOR BARRIER. (So perforated or chips would do.) Last edited by Slavic381; 09-26-11 at 08:54 PM.. |
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