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.


There's at least one other consideration: Looks.

Light-colored roofs discolor from the crap in the air and show unsightly
streaks downstream from vents, chimneys, and other protrusions.

I don't see how snow melt can be affected by the roof color. True, dark
roofs absorb more sunlight and get warmer, but if the roof is covered with
snow, the sunlight's not reaching the roof...

But, I admit, I don't know much about snow. We get snow - maybe a
quarter-inch - once every ten years. 'Course that's cause for panic: they
close the schools, drivers collides with as many other cars as they can
because that's what you're supposed to do when it snows, people stock up on
canned goods and huddle in their family, preachers inform us that the end is
nigh, there are the obligatory news reports of kids making one-foot tall
snowpeople with film of goofy dogs and perplexed cats trying to make sense
of the phenomenon.

Snow in Houston is a truly remarkable experience.