A couple of enterprising Cornell University grads took what they learned competing in the Department of Energy's 2005 Solar Decathlon and created a consulting firm that helps homeowners save money by lowering their energy bills. Based on your particular home's schematics, Zero Energy Design
recommends efficiency-boosting improvements and works with local contractors to calculate what it'll cost to make them in your area. For new construction, energy savings are 30 to 50 percent. Reports from $4,000.