Posted by W on February 9, 2011, 1:26 am
There is an outfit in the San Francisco Bay Area named Eagleshield that
pushes the use of a reflective liner on the inside of the roof, to reflect
away solar heat during summer. Is anyone familiar with this kind of
product and how well does it work?
Are there strong differences in the quality of the material used for such
reflective insulation, and what are the scales or criteria used to specify
the highest efficacy material. I would be tempted to have a third party
do the install but want to make sure I don't compromise on the material.
--
W
Posted by W on February 9, 2011, 9:40 pm
> W wrote:
> > There is an outfit in the San Francisco Bay Area named Eagleshield
> > that pushes the use of a reflective liner on the inside of the roof,
> > to reflect away solar heat during summer. Is anyone familiar with
> > this kind of product and how well does it work?
> If you live in a hot area, this will boost your roofing temp
significantly,
> decreasing its life, unless there is very good venting above the
reflector.
Would installing a ridge vent at the top of the roof address that concern?
I guess with a ridge vent you would accelerate cooling of the attic, and
without sufficient insulation you would accelerate cooling of the home as
well?
--
W
Posted by Michael B on February 11, 2011, 11:11 am
I am just not impressed with a plastic product that is
going to be installed at the hottest part of the house.
Unless there is a nonprorated guarantee of at least
20 years, for a company that will still be around to
honor it.
And able to be installed without special instructions,
and the payback period...well, you get the idea.
I'm simply not impressed.
A ridge vent, with suitable soffit venting is IMO the way
to go.
And a reminder. If you don't have a minimum of one
square foot of vent per 300 feet of vented space, you
likely have no guarantee on your shingles. And for the
sake of comfort, it should be per 150 feet or better.
regardless of what else you put in your attic, the paperwork
for the shingles calls for VENTING. Any questions, I suggest
calling the Owens-Corning folks at 1-800-ROOFING
> > On 2/9/2011 1:28 PM, Bob F wrote:
> > > W wrote:
> > >> There is an outfit in the San Francisco Bay Area named Eagleshield
> > >> that pushes the use of a reflective liner on the inside of the roof,
> > >> to reflect away solar heat during summer. Is anyone familiar with
> > >> this kind of product and how well does it work?
> > > If you live in a hot area, this will boost your roofing temp
> significantly,
> > > decreasing its life, unless there is very good venting above the
> reflector.
> > Do you have any real evidence of that? I put a radiant barrier under
> > half of my roof and then compared temperatures on the two halves with an
> > infrared thermometer, being careful to measure at the same time, under
> > full sunlight and at the same angle; I found no measurable difference in
> > temperature. I do know, however, that my A/C costs dropped considerably
> > when I installed the radiant barrier.
> How did you do the installation? Did you have any kind of soffit vent, or
> did you mount the radiant barrier across the roof supports so as to allow an
> air channel between the radiant barrier and the roof?
> Did you mount it only on the south facing part of house? Why did you do
> just half the roof?
> Which vendor and brand of reflective material did you use? Was there any
> reason to prefer one brand over another?
> Not being familiar with radiant barriers, are they reflective on both sides?
> Doesn't dust accumulation lower their effectiveness at some point?
> What kind of reduction did you see in AC usage?
> --
> W
Posted by W on February 11, 2011, 5:40 pm
Will a ridge vent have the downside of tending to make the attic colder
during the Winter?
It seems like you would want to have a system where the vents open during
heat but shut during lower temperatures.
--
W
I am just not impressed with a plastic product that is
going to be installed at the hottest part of the house.
Unless there is a nonprorated guarantee of at least
20 years, for a company that will still be around to
honor it.
And able to be installed without special instructions,
and the payback period...well, you get the idea.
I'm simply not impressed.
A ridge vent, with suitable soffit venting is IMO the way
to go.
And a reminder. If you don't have a minimum of one
square foot of vent per 300 feet of vented space, you
likely have no guarantee on your shingles. And for the
sake of comfort, it should be per 150 feet or better.
regardless of what else you put in your attic, the paperwork
for the shingles calls for VENTING. Any questions, I suggest
calling the Owens-Corning folks at 1-800-ROOFING
> > On 2/9/2011 1:28 PM, Bob F wrote:
> > > W wrote:
> > >> There is an outfit in the San Francisco Bay Area named Eagleshield
> > >> that pushes the use of a reflective liner on the inside of the roof,
> > >> to reflect away solar heat during summer. Is anyone familiar with
> > >> this kind of product and how well does it work?
> > > If you live in a hot area, this will boost your roofing temp
> significantly,
> > > decreasing its life, unless there is very good venting above the
> reflector.
> > Do you have any real evidence of that? I put a radiant barrier under
> > half of my roof and then compared temperatures on the two halves with an
> > infrared thermometer, being careful to measure at the same time, under
> > full sunlight and at the same angle; I found no measurable difference in
> > temperature. I do know, however, that my A/C costs dropped considerably
> > when I installed the radiant barrier.
> How did you do the installation? Did you have any kind of soffit vent, or
> did you mount the radiant barrier across the roof supports so as to allow
an
> air channel between the radiant barrier and the roof?
> Did you mount it only on the south facing part of house? Why did you do
> just half the roof?
> Which vendor and brand of reflective material did you use? Was there any
> reason to prefer one brand over another?
> Not being familiar with radiant barriers, are they reflective on both
sides?
> Doesn't dust accumulation lower their effectiveness at some point?
> What kind of reduction did you see in AC usage?
> --
> W
Posted by Pete C. on February 11, 2011, 7:28 pm
W wrote:
>
> Will a ridge vent have the downside of tending to make the attic colder
> during the Winter?
The attic is supposed to be cold in the winter, warm attics cause ice
dams.
Attics are not conditioned spaces, the floor of the attic is where the
insulation is supposed to be to keep the heat in the house in the winter
and out of the house in the summer. The attic is supposed to be a well
ventilated buffer space.
> > There is an outfit in the San Francisco Bay Area named Eagleshield
> > that pushes the use of a reflective liner on the inside of the roof,
> > to reflect away solar heat during summer. Is anyone familiar with
> > this kind of product and how well does it work?
> If you live in a hot area, this will boost your roofing temp