So you want the government telling you what you can and cannot do with your house? I know if I had paid $500k for a home I sure as hell wouldn't want someone telling me what color I have to paint it. White on the streets seems like it would be dangerous for driving.
No, i'm saying that if we know painting the roof white will help X amount, and the govt offers people a choice of not doing it, or reeiving $Z to paint the house, I'm okay with that.
make it voluntary. I know a lot of people who would paint their house pink for $2k right now.
besides - it doesn't have to be white. There is a special paint that look clear that will reflect light the same, and your roof will look the same.