[RE-wrenches] Personal project: roofing colors

[Joel Davidson]

William,

There's lots of good technical data (and also wild advertising claims) on 
the www if you google "cool roofs". Smooth white roofs (metal or non-metal) 
reflect heat well. Several years ago the US Bureau of Standards tested 
composition shingles and found that so-called white comp shingles got almost 
as hot as black shingles because of their granular texture and asphalt 
subsurface.

It is worth noting that light gray or "white" asphalt shingles have a 
measured solar absorptance of approximately 75% as opposed to true 
reflective roofing systems which have absorptances less than 30% (Parker et 
al., 1993B). Dark gray shingles have a solar absorptance of about 90%.
...from http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-336-98/

Joel Davidson

----- Original Message ----- 
From: "William Miller" <wrmiller at charter.net>
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Sent: Wednesday, September 24, 2008 9:05 AM
Subject: [RE-wrenches] Personal project: roofing colors


> Friends:
>
> I have an energy question on a personal project.  We are adding two rooms 
> to our house and it is time to select roofing colors.  Nothing will match 
> the weird comp shingles already on our roof, so we are going to not match 
> and re-roof the rest of the house later.  In the meantime, I need to pick 
> a shingle color.  How much difference does a lighter roof color make here 
> in our inland California (Mediterranean) climate?  We get over 100F 
> frequently in the summer.
>
> Thanks for your insight.
>
> William Miller
>
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