Though written in 2007, an analysis by RENEW's executive director Michael Vickerman may be even truer today an a few years ago, given the risk involved in "traditional" investments. The analysis shows that an investmnet in a solar hot water system generates a better rate of return than putting money in the bank:I wrote a column which was highly critical of using payback analysis to figure out whether installing a solar hot water system on one’s house makes economic sense. In almost every example you can imagine, the payback period for today’s solar installations ranges between long and forever. For my system, which started operating in January 2006, payback will be achieved in a mere 19 years using today’s energy prices, though by the time 2025 rolls around, half of Florida might be under...