The result is this West Seattle gem, a three-story, 3,160 square foot net-zero energy home located on an urban infill lot. It features a ground floor one-bedroom mother-in-law apartment with three additional bedrooms on the main two floors. Flexibility was key in the design to allow the house to continue to be functional as the homeowners' young family grows. With that in mind, there are "flex" spaces on each floor, right-sized bedrooms, a generously sized utility room, and ample outdoor spaces.