Utilizing an efficient structural system and modular design creates economic leverage to optimize building energy performance. Insulation levels exceed the requirements of model codes, and the green roof provides additional insulation and summer transpiration. Optimized glazing and a narrow building section allow daylight to enter all occupied spaces. The geo-exchange system uses electric pumps for both heating and cooling, eliminating on site combustion and the production of CO2. Fully equipped for plug-in electric vehicles, the garage includes two electric vehicles provided by the developer as share rides for use by the residents.