High-quality finishes, namely lighting fixtures and an FSC-certified plank wood floor common across the entire first level, add to the overall appeal. “If it feels like 1,600 square feet, you’ve succeeded,” he says.
Integrating a checklist of green building methods and materials was far less challenging, if equally impressive.
Leveraging the region’s EarthCraft House New Homes program, Oliver and builder Martin-Dodson Homes raised the bar by involving the Atlanta-based Southface Energy Institute and the federal Building America Consortium’s Builder’s Challenge, a program that is driving toward a critical mass of net-zero-energy homes by 2030.
To that end, the Nest Cottage is properly oriented to the sun and designed for passive solar gain, daylight, and natural ventilation to reduce the energy load on mechanical equipment—primarily, a right-sized, closed-loop geothermal heat pump that taps the constant temperature of a nearby lake.
Structurally, the cottage features 2x6 wall framing filled and air-sealed with full-cavity Icynene open-cell foam insulation. A rubber-polymer coating akin to a below-grade waterproofing membrane replaced traditional housewrap as a more effective air and water barrier behind a durable and prefinished fiber-cement lap siding. Those measures helped the home score a HERS index of 32, one of the best in EarthCraft history.
With a tight thermal shell in place, the project team then specified Energy Star–labeled appliances and lighting, no-VOC paint, and a wood-burning fireplace that provides fan-driven supplemental heat on chilly nights but otherwise effectively blocks air transfer into and out of the house.
Outside, “night-sky” lighting fixtures block uplighting to preserve stargazing opportunities, reduce light pollution, and save additional energy, while native (and some fruit-bearing) landscaping will be irrigated by an on-site greywater reclamation system to reduce water use.
Integrated measures to reduce the home’s electrical load enabled a 14-panel, 3-kW array of solar electric panels to offset almost all of the grid-supplied power and earn utility credits toward a possible net-zero annual balance. All told, the little house should achieve an 80% reduction in overall energy use compared to the current Building America benchmark, cost between $200 and $450 a year to heat and cool (depending mostly on lifestyle behaviors and local utility and energy buy-back rates), and become the highest-rated EarthCraft House ever built—a standard that the remaining cottages are anticipated to match.
For all of its attributes, however, the Nest Cottage almost didn’t make it to Serenbe.