LEED Certification level: Platinum
Builder: Evolutionary Home Builders
Oak Park, IL

The homeowners put a premium on indoor air quality and low energy consumption and recognized that quality design would allow more investment in a smaller project. A modest plan size was developed (1,700 square foot net, 1,960 square foot gross), with slab-on-grade first floor. The upper level slopes up to the south to capture sky views and solar gains; the stair allows that light and energy to flow to the main level. The front-screened porch is a reinvention of the traditional front porch — a place to socialize, enjoy the outdoors and enjoy fire on cool evenings.

Great care was taken in specifying non-toxic materials: no-added formaldehyde cabinet construction with water-borne finishes, zero VOC, nontoxic floor finish and paints, Greenguard certified drywall and subfloor adhesives, caulks, and sealants, salvaged wood (not previously finished), etc. Third-party air quality testing showed total VOC of only 48 parts per billion prior to move in, and formaldehyde of 46ppb. The CARB residential formaldehyde guideline is below 27ppb for residential chronic exposure. Since we had no specified added-formaldehyde construction materials, our count is likely due to furniture and other off-gassing, and will drop as the house is ventilated. Mold readings were below outdoor air.

An energy monitoring system was installed so the owners and design team can track energy use compared to modeled predictions. Measured results also contribute to a clearer understanding of energy use for future energy models across the industry, which is one of PHIUS’ objectives. Although early in occupancy, the owners appear to be running this all-electric house at about 500kWh per month, below the modeled prediction. The owners plan to install a PV array within the next year.