mnm Mod

Efficient by Necessity: Being an island and all, Iceland is a place where "resources are scarce and everything is valued, used, reused and re-reused," says Erla Dogg Ingjaldsdottir, founder of Minarc Inc. architecture firm. She and her husband brought the lean-minded ideas of their home country to California, where they build affordable, high performance, net-zero energy buildings (meaning the potential for zero energy consumption and/or carbon emissions).

How They Do It: Delivered and assembled on site or in a factory, Minarc's metal-framed kit houses are more affordable because they are precut, eliminating custom onsite building. Floors contain no plywood or wood studs; windows are low to draw cool air in at night; and green materials are used whenever possible, from recycled tire laminate on kitchen cabinets, to concrete exterior walls made of partly recycled fibers. The house itself is also recyclable -- everything can be taken apart and sent back to the manufacturers to be reused.

Cost: $255 per square feet for this mnmMod Santa Monica home, including foundation

Timeline: Four months to assemble a one-story kit