Because green features aren't always included on the cost tab, they reflect lower resale values. Banks, in turn, won't fully finance the homes, leaving buyers with a bigger check to write for the down payment.
Adding a green feature will probably resell at a fraction of the price if the concept isn't popular, argues David Snook, a California-based appraiser who serves on the real property committee on education for the American Society of Appraisers.
"It doesn't do a lot of good to simply add value based on cost...[since] cost does not necessarily equal value. The question is 'How much will the market pay on resale?'"