Pashington, D.C., Mayor Adrian Fenty (D) Aug. 11 signed a new law that sustainability advocates hope will spur demand for energy-efficient space in commercial buildings. The Clean and Affordable Energy Act will require all privately-owned commercial buildings over 50,000 sq ft to be evaluated and benchmarked annually with the Environmental Protection Agency’s Energy Star rating system beginning in 2010. The system scores the energy efficiency of commercial buildings on a 1-100 scale. The rating requirement will encourage landlords to place a higher value on energy efficiency, says Tom Petty, a partner with the real estate practice of Anderson Kill & Olick, Washington, D.C. “The new law will put a giant yellow sticker on the side of every building. Tenants will demand energy efficiency,” he says.