2. "Igloo" Walls The homes are built with panels of steel encasing a core of rigid foam. Just three inches in diameter, they offer 40 percent better energy efficiency than thicker wood walls.
3. Sustainable Materials Make It Right uses paints, adhesives, and varnishes that are low in volatile organic compounds, which can damage the liver, kidneys, and central nervous system. The carpets are recycled nylon 6 rather than the potentially toxic plastic PVC. The porch and beams are TimberSIL, a fusion of wood and glass that resists water rot and insects better than lumber.
4. Lighting and Appliances The windows in a Make It Right home are made with insulating glass that lets in maximum light but deflects unwelcome heat and ultraviolet rays. The lightbulbs are CFLs, which consume 75 percent less energy than incandescents; the dishwashers, fridges, and washing machines are Energy Star–certified.
5. Rain Capture In a downpour, rain slides off the roof into a series of pipes and gutters to collect in two 300-gallon cement cisterns, reducing runoff. Residents can use the water to irrigate their property with a remote pressure pump.
6. Geothermal Heating and Cooling About 20 feet below residents' backyards, a system of pipes absorbs the ambient heat of the Earth—which stays between 45 and 70 degrees year-round—and pumps it into their houses, taking pressure off boilers in winter and air-conditioning units in summer.