This 1,800s.f. Passive House (seeking PHIUS+ certification) is designed to harmonize with its site by taking advantage of the sun, views to mature oak trees, and its quiet setting at the western edge of Downers Grove. The interior is organized around a large south opening to a courtyard-like patio space; as a backdrop to this opening is a wall featuring walnut from trees harvested on site. Openings in this feature wall bring natural light deep into the house. As a Passive House, it uses about a tenth the heating energy of a built-to-code home, and about 65% less energy overall; it is also designed to be Zero Energy Ready, meaning that with the addition of a solar electric array, the house can produce as much energy as it uses. Indoor air quality and occupant health are a primary objective as well, so no-added-formaldehyde panel materials, no-VOC, non-toxic paints, and Greenguard certified sealants, caulks, and adhesives were used along with a continuous demand-controlled ventilation system to provide superior air quality.