This episode is set at the Macallen Building, Boston's first LEED-certified condominium building and a large-scale example of sustainable design. Host Kevin O'Connor goes to the middle of Texas (Dripping Springs and Johnson City) to understand the mechanics and benefits of rainwater collection. At the International Builders' Show in Las Vegas, Nev., licensed contractor and host Amy Matthews checks out a heat pump that retrofits onto existing water heaters to make them more efficient. In Knoxville, Tenn., Kevin sees the Clayton i-House, a low-cost, high-tech offering from the country's largest maker of manufactured housing. Amy goes to New Orleans, La., to dig into an example of the latest backyard trend: urban gardening. Kevin and Amy unpack the particulars of Leadership in Energy and Environmental Design (LEED) certification, and Amy demonstrates the benefits of cotton insulation.