In a factory in Nevada, a large 3D printer prints the pieces of new prefab tiny homes that can work fully off the grid. When complete, the houses will run on solar power, including heating and cooling. An optional system generates water from moisture in the outdoor air so it isn’t necessary to connect to a city water supply. In the bathroom, the home is among the first in the U.S. to use a new shower that cleans and recycles water. The house, from a startup called PassivDom, is designed to use as few resources as possible. The company didn’t initially aim to create an off-the-grid home, but realized it was possible as it experimented with materials to improve energy efficiency, landing on a polymer composite. “It was strong and efficient, and it helped us build houses with 20 times less energy consumption than usual buildings,” says Max Gerbut, CEO and founder of the company.