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Radiant Barrier
#1
I don't know why, but I've been on this massive home improvement kick lately. While looking into ways to keep my attic cooler and keep from damaging the networking gear I have up there now I've started reading about this new radiant barrier stuff they are putting into new construction. It's basically a aluminized sheet product that you put on the attic floor and between the roof joists that reflects the solar gain back through the roof. It seems like from what I'm reading it can make substantial energy savings and it really doesn't seem that expensive all things considered and seems fairly easy to install. I'm wondering has anyone installed a radiant barrier in their house how much of a dent did it make in your utility bills? I'm also wondering if it's really worth it in our area where it doesn't get as hot as say Arizona....

http://energy.gov/energysaver/articles/radiant-barriers
The forum poster formerly known as Emoticon...
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#2
Wouldn't you also then lose the benefit of the additional heat source over winter?
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#3
gnbrotz;140850 Wrote:Wouldn't you also then lose the benefit of the additional heat source over winter?

Theoretically yes, but from what I'm reading they say if you also lay radiant barrier down on the floor of the attic it also reflects the heat being lost through the ceiling back down so it sort of counteracts the winter loss in solar gain.

BTW: Found a lot of good PA specific info here...

http://www.engr.psu.edu/phrc/training/Ra...203-13.pdf
The forum poster formerly known as Emoticon...
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#4
Get ready to put new shingles on your roof every year...
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#5
Mr_Gixxer;140852 Wrote:Get ready to put new shingles on your roof every year...

And if one has a metal roof?
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#6
gnbrotz;140853 Wrote:
Mr_Gixxer;140852 Wrote:Get ready to put new shingles on your roof every year...

And if one has a metal roof?

Not sure. I've done about a dozen roofs either going from shingled to shingled or from shingled to metal and I've seen first hand what excessive heat and poor ridge ventilation can do to shingles. I'm assuming this radiant barrier radiates the heat away from the structure? Sounds like a recipe for disaster especially on a roof that has a side that always faces direct sunlight 365 days a year although I have no experience with this radiant barrier stuff.
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#7
From what I've been reading they say radiant barrier doesn't effect the temp of the shingles by more than 10 degrees F. Either way there are way hotter places to live than PA. Still though after reading that paper I posted I think I'm going to start by wrapping the ductwork in the attic and see what efficiency gains there are to be had there.
The forum poster formerly known as Emoticon...
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#8
Emoticon;141442 Wrote:From what I've been reading they say radiant barrier doesn't effect the temp of the shingles by more than 10 degrees F. Either way there are way hotter places to live than PA. Still though after reading that paper I posted I think I'm going to start by wrapping the ductwork in the attic and see what efficiency gains there are to be had there.

Do you have a ridge vent on your roof?

This is probably the best way to keep your attic cool without installing electric fans. All you'd have to do is peel the ridge cap off all the way across and cut the decking 3 inches on each side. Next you'd get a roll of ridge vent, something like this and nail it on and re shingle the top. You can even build a soffit underneath with vents to make it look better if you have a finished attic.
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#9
In my travels I've come to the following conclusion...

Unless being used in conjunction with a energy truss design and the required R-38 ceiling insulation value of new construction I don't believe you'll find the gains you hope for. It could go as far as creating problems for you in the form of ice and water penetration from the freeze thaw cycle, depending on roof slope, use of ice/water sheild, shingle, etc.

If it were me on an existing structure I would spray foam insulate.
It may cost a bit more up front but in the long run you will, with no doubt, see the benfit.
*On a metal roof it'll cut down on the noise when it rains.

Just my .02.
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