Urban Oaks, a subdivision near Prairie High School, springs out from the fields. Its more than 100 homes are new, sleek and modern; but their most important trait may be that they are being purchased. They are energy-efficient homes. Most don’t show the telltale solar panels on the roof, but they are built airtight and are primed for all sorts of energy savings. Developer Troy Johns said it only seemed recently that buyers started showing interest in these features.