Saving the Planet and Whatnot

In rough numbers, let's say there are 100 million houses in the U.S. that could benefit from one of these standard greening investments:
- Solar panels- Whole house fans- Improved wall insulation- Better windows- Sealing and insulating all ducts- Improved roofing with radiant barriers

Each of those investments would pay for itself if only you could solve the financing problem. No one wants to plunk down a pile of cash today for a house he might sell tomorrow. And if your payback is over ten years,