At Green House Data in Cheyenne, Wyo., energy efficiency is an obsession. When someone enters one of the company’s secured data vaults, they’re asked to pause in the entryway and stomp their shoes on a clear rubber mat with a sticky, glue-like finish. “Dust is a huge concern of ours,” says Art Salazar, the director of operations. That’s because dust makes electronics run hotter, which then means using more electricity to cool them down. For…