Over the last several years, REEF has been asked to look into various "green" consruction materials, systems, and techniques.  Often times, after intense research, consultation with experts, and a common sense assessment, we have found that although many of these products and concepts are innovative, environmentally responsible, and efficient, many of them are still unproven, and the ultimate decision comes down to cost and return on investment.  See this article from Investopedia regarding assessing green residential construction http://www.investopedia.com/articles/mortgages-real-estate/10/green-home.asp#axzz1fC1HRKks