Passivhaus Finds a Home in the Bayou State

Although sustainable materials and energy efficient design have found their way into some post-Katrina residential rebuilds on the Gulf Coast, Louisiana isn’t otherwise known for leading the charge to greener home construction. And that puts the house built by architect Corey Saft at the forefront of green housing in the state.

The home, a 1,200-sq.-ft. three-bedroom, two-bath in the south-central town of Lafayette, is in fact an anomaly in Louisiana, mainly because Saft designed it to qualify not only for LEED Platinum certification but also certification by Passive House Institute US.

Saft, a professor of architecture at the University of Louisiana, told the Lafayette-based news daily The Advocate that the building’s energy-recovery ventilator – an UltimateAir RecoupAerator, with MERV 12 filters – will deliver exceptional air quality. The home’s overall airtightness and shell insulation, he adds, make it “a little bit of an experiment” for housing in the Louisiana climate.

Insulated and airtight
Called the 204House, the project features R-28 Icynene LD-R-50 walls and an R-55 Icynene LD-R-50 roof, with 2x6 and 2x8 advanced framing, Saft noted in an email to GBA. The exterior walls are wrapped in 1-inch polyisocyanurate, the roof in 2-inch polyiso. Siding consists of pre-painted fiber cement board and white standing seam metal panels. Saft said there is a 1-inch space between the siding and the polyiso to help “shade” the walls and prevent heat and moisture buildup.

R-21 extruded polystyrene (XPS) was used for the basement/crawlspace walls, and R-16.5 XPS under the slab. Saft also used SeriousWindows’ 501 series vinyl-frame windows, with SeriousGlass 8 double-pane glass.

The one renewable-energy component of the house is a 3.25-kW thin-film photovoltaic system by Houston-based WhirlwindSolar.