Three miles northeast of the White House, now topped with solar panels, six modest new rowhouses are expected to deliver world-class savings in energy.
The reason's simple: They're so well sealed and insulated that they perform just like a coffee thermos. No furnaces are needed, because they're projected to use up to 90 percent less energy than a typical house.
Built partly by volunteers, these low-budget Habitat for Humanity homes—now nearing completion—don't look like anything special. They have basic brick facades like others in their gentrifying Ivy City neighborhood.
They stand out in other ways: 12-inch-thick exterior walls and triple-pane, imported-from-Ireland windows offer more than double the insulation required of new homes. In lieu of a furnace, tiny, wall-mounted Mitsubishi units provide
