Comment Metal Roofing (Score 3, Informative) 52
Years ago I owned a highly renovated one room brick schoolhouse (ground-source geothermal heat pump, radiant floor heating, two stories). The attic was cooled with a power vent (at some temp (I think it was like 115f) a central fan would come on and push hot air through a single top vent and pull it up through the eves). In the summer almost every afternoon when it was sunny you could hear the power vent come on.
About 10 years into ownership I installed a metal roof with a slate-like look. The company claimed that the roof would make the schoolhouse more energy efficient by reflecting a lot of the incoming solar heat. Well, the power vent *never* came on again in the 3 years after I installed the roof. At one point I even checked to make sure it was still working. In fact the A/C would only come on maybe a couple of times per summer instead of almost every day.
The install cost was about double what shingles would be, but next time I have to install a roof I'm doing the same thing. These things have a lifetime non-prorated warranty unlike shingles which are prorated. I don't have the house anymore and I'm not affiliated with the company in any way.