In January 2008, Iowa State was selected by the U.S. Department of Energy as one of 20 teams to participate in the fourth Solar Decathlon, October 9–18, 2009. The prestigious event is a competition to design, build, and operate the most attactive, effective, and energy-efficient solar-powered house. The houses will be judged in 10 contests while open to the public in a Solar Village on the National Mall in Washington, D.C. Iowa State’s Interlock House was designed and built by dozens of students from 11 departments. The 800-square-foot solar-powered house is expected to produce more energy than it consumes. It is targeted for a retiree market and is ADA accessible.