The first Passive House-certified homes in Philadelphia will soon be ready for occupancy. The first of 27 units in the Stables development from the Onion Flats group and Domani Developers will be completed by the end of the month. 

The ultra-energy-efficient structures will generate 100 percent of their power from a 4.23kW PV array. Super-insulated exterior envelopes will significantly reduce the need for heating and cooling and thus decrease the overall operating costs. Other sustainable features include a 95-percent permeable site including green roofs and porous paving for managing stormwater, R-34 walls and R-52 roofs, and triple-pane Intus windows and doors. Energy-monitoring systems will help homeowners follow energy consumption in their homes. 

The factory-built dwellings will consume up to 90 percent less energy than traditionally built homes. Designed in the city’s prevalent rowhouse style made it an ideal model for modular manufacturing. Foundations were constructed on site, while the rest of the structure was built in a factory, reducing construction time by 50 percent. 

The project was significantly downsized from the original plans’ 70 units to 27 unitsdue to financing difficulties, says Onion Flats principal Tim McDonald. ”It’s been taking usto many different banks to come up with something that would make it work,” he says.