WHEN A BELLEVUE-AREA family approached Thomas Jacobson to build the ultimate energy-saving house, the contractor saw the chance he’d been waiting for. He had built his business, Thomas Jacobson Construction, on sustainability, but had not yet completed a totally self-sufficient structure. “The owners came to us with two criteria: environmental friendliness and high air quality,” said Jacobson, who collaborated on the project with George Ostrow and Carrie Anderson of Velocipede Architects. Dubbed the Northwest Net Zero House, it’s designed to run only on the energy generated by its solar panels and the rainwater funneled off the roof. The house received LEED Platinum certification in January, and Jacobson’s water system had proved so innovative that King County had to write new code to approve it.