Orientation and careful planning were key elements in reaching sustainability goals for the Lusche residence, which was the first home to achieve the highest level of certification in the Home Builders Association of Alabama’s EnergyKey rating system, developed in 2006 in partnership with Southface Energy Institute. The project focused heavily on energy efficiency, a crucial component of EnergyKey certification.
During the design phase, the architects’ San Antonio, Texas–based energy modeler ran several computer-generated programs using REM Rate software from Architectural Energy Corp. that showed the team how various insulation strategies, wall assembly decisions, and other building volume details would affect projected HVAC loads. The results of the $2,500 modeling convinced them to use open-cell spray-foam insulation, seal wood-to-wood wall connections within the framing, spec a 16-SEER Trane heat pump, and move the insulation line from the ceiling to the roof plane so that all ductwork would be in conditioned space.
With the ultra-insulated shell and fine-tuned heating and cooling load, Hinson and Dagg were able to right-size the HVAC equipment, reducing the spec by almost 6 tons, saving more than $20,000 in system costs. “The reduction in the mechanical system size paid for the energy modeling many times over,” says Hinson, noting that they’ll do the same for all their future projects.
Due to the increased tightness of the exterior envelope, the architects included an Alpine ERV system with Honeywell fresh air dampers to ensure adequate fresh air intake when the windows are closed. Other energy-saving features include light-colored metal and fiberglass composite roofs; R-5 insulated foundation walls; Energy Star–rated appliances, bath fans, and light fixtures; and two high-efficiency electric water heaters.
WaterSense-labeled toilets and faucets help reduce water usage inside, while the site design—which preserved 96% of the property’s hardwoods, minimizes rainwater runoff, and utilizes native plant species with low water requirements—conserves water outside.
“Compared to a typical Alabama custom home, we have a postage-stamp-size sod area—less than 2,000 square feet,” Hinson explains.
Still, building a third party–certified house in a rural area with no statewide energy code and few green raters, verifiers, or eco-minded subcontractors proved challenging. The architects, both professors at nearby Auburn University’s College of Architecture, Design and Construction, fell back on their years of experience as green educators and advocates in seeing the project to completion.
“This isn’t Seattle; we’re on the frontier of the residential green building movement here,” says Hinson. “We’ve had to do a lot of convincing to get these ideas out there into the housing marketplace.”
Jennifer Goodman is managing editor of EcoHome.