Imagine Mount Airy as a green oasis. Designed by Re:Vision architects, this clean, LEED-certified multiuse building will soon occupy 520 Carpenter Lane. The Seibert brothers of Bancroft Green, developers responsible for the only green multihome development in Center City, are planning to open a 25-unit condo and coworking space where they will move their headquarters. A public courtyard and garden will round out the scenic offerings. Plans are for a Passivhaus design to consolidate energy use among the units, placing this edgy complex in line with leading German and Scandinavian low-energy construction.