Rob wrote:
What are the trade-offs regarding home roofing reflectance. I ask because
I'm considering using a 40% R roof for most of my home (mostly for
asthetic reasons) and a 60% R for a south facing (and not ground visible)
large dormer we have -- mainly to reduce heat load in the summer which has
been a problem.

Is there a down side to this. Some people seem to want to use darker
roofs so the snow melts faster -- others say it's good for snow not to
melt and a cooler roof is better in both the winter and summer.

I live in minnesota -- so we get both very cold and quite warm -- but only
a moderate amount of snow usually.

Thoughts?

Rob
It's been six or seven years since I did much research about roofing
problems. I did run across info about the heat on the surface of light
vs. dark roofs. Dark=hotter, of course. I'm in FL, so the fact that
cooler light roofs grew more mold was of interest. One thought that I
believe I read but can't be sure, is that the surface temp didn't
transfer to an important degree to the attic temp; i.e., didn't make
much difference in the attic temp on the basis of light/dark shingles alone.

From doing a quick Google search, I think the answer is "It depends" )
Climate, orientation, roof style, underlayment, insulation, etc.

Search on 'roofing color heat attic'.

Here is a pretty good link:
http://www.peaktoprairie.com/?D=206