Net Positive Home* | Chicago (*electrical only)
The goal for this residence was to create a home that produces more electricity than uses and is a minimal size to optimize yard space. The reduced size (2800 sq. ft.), tight construction bordering on Passivehaus levels, highly sustainable building systems, and passive techniques combined with a 6.2kW garage mounted PV array were designed to exceed Net Zero levels for its electrical use. The smaller house footprint provided a larger yard, supplemented with a fully developed green roof system. The home achieved a HERS rating of 32 and an EUI rating of 23.
To provide enough electric power production, the garage was covered with (24) 260W PV panels mounted at their optimal angle. The annual power production is expected to be 7840 kWh and the annual electric usage is anticipated to be 4800 kWh. Surplus electricity will partially charge their electric car. The owners specifically requested that the home have a gas fired furnace, water heater, dryer and cooktop. A larger PV array, which would have fit on the main roof, would have provided enough renewable energy to make the house fully Net Zero in conjunction with using air source HVAC systems, an induction cooktop, and a hybrid dryer and water heater.
While the predominant east/west orientation constrained passive solar possibilities, natural daylighting was obtained through careful window placement and a central skylight from the roof down to the basement. The windows were selected based on orientation specific solar heat gain coefficients and solar shading coefficients. Natural ventilation was achieved by venting hot air out of the third floor penthouse windows while drawing in cooler air from the basement and first floor.
+ GREEN FEATURES
Reclaimed local wood for the cabinets and flooring
Air to Air heat exchanger for fresh air intake
Centrally controlled, smart thermostats
Outside combustion air for the fireplace
Ultra high efficiency mechancial system
Stacked air vent passive system
Water Sense™ plumbing fixtures
Ceiling fans for air movement
Garage mounted solar panels
Low water landscape garden
Cement fiberboard siding
Energy Star appliances
LED lighting throughout
Green Roof system