Mattamy Homes, North America’s largest privately-owned homebuilder, was chosen as one of five homebuilders by Owens Corning to participate in the ecoENERGY Innovation Initiative (ecoEII). Mattamy designed five Net Zero Energy Homes (NZEH) for the program, the first completed in November 2015 in Calgary’s Cityscape community. Each home is designed to produce as much energy as it consumes over a year. Mattamy constructed two research homes to test the NZE building envelope and new building practices for the Cityscape development. The NZEHs were tailored for cold climate, doubling thermal performance with energy-efficient high-performance walls. An exterior air barrier was also used, enabling Mattamy to achieve NZE and PassiveHaus levels of air-tightness, producing a home 70% more energy efficient than a code built equivalent. Collaboration with SAIT Polytechnic’s Green Building Technologies and students helped Mattamy to develop a production-friendly way to build new NZEHs.