I was in Ames this past weekend where my friend Eric Berkson, IT Coordinator for the Iowa State Solar Decathlon team, gave me a tour of their solar powered house under construction. Called the Interlock House, it utilizes a NanaWall system on the south facade to create a versatile sunspace that can be closed as a solar-collecting greenhouse in winter, a recessed exterior porch for summer, or completely open for cross-ventilation. It is a very cool system. The 2009 Solar Decathlon competition will be held October 9 – 18, on the National Mall in Washington, DC, where the Interlock House and 19 other competing solar houses will be reconstructed and open to the public. The Interlock House website includes an interesting photo blog, which I borrowed the following photo from.