Sun-Soaked West Virginia Home Goes Net Zero

High-Performance Systems 

Coleman oriented the home 10-degrees east of south to reduce heat gain during the summer, and maximize solar gain during the winter. She also designed window overhangs that do the same. Double-pane, fiberglass-framed casement and awning windows incorporate a maximum U-factor of 0.28. (The lower the U-factor, the higher the insulation properties and the windows’ resistance to heat transfer.)

The house is oriented to capture the winter sun through those windows and passively heat the home. The four-inch-thick, concrete slab-on-grade floor has three inches of rigid-foam insulation with an R-value of 15. The doubled two-by-four stick-frame walls are on 16-inch centers with a half-inch space in-between. The result is an eight-inch-thick wall where fiberglass batts and closed-cell spray foam insulation bring the walls to R-36. The home’s roof was framed with manufactured wood trusses to allow for lots of fiberglass batt and spray foam insulation in the vaulted ceiling.

To combat the region’s hot, humid summer climate, the clerestory was key. “When we open those windows, the hot air goes up and out, while the operable windows on the first level bring cool air in,” Palmer explains. “I can feel the cool air moving across my ankles.” A whole-house fan in the attic also helps move air through the home. In mid-summer, when the high temperatures and humidity last well into the night, the couple turns on their multi-zone mini-split for additional cooling.

Most mini-splits operate like a standard air-source heat pump, with an outdoor condenser/compressor, but without the expense or space required for ducts. In this home, without ducts, conditioned air wouldn’t be able to reach the bedrooms. An eight-inch-tall ducted air handler was concealed in the hallway’s dropped ceiling, to preserve the ceiling’s thermal integrity. The duct runs down the hall to feed into the bedrooms. The ducts were routed in the attic above the primary ceilings and buried under 16 inches of blown-in fiberglass insulation.

The home’s 6.3 kW PV system generates about 700 kWh per month; the house, however, consumes about 563 kWh per month. While the kitchen has a propane cooktop and the wood-burning masonry heater, the home has all-electric appliances. Much of the home’s winter heat comes from the unique, masonry wood stove at the center of the home.  

The dining room has a large bay window with east, south, and west: the porch blocks most of the late afternoon summer sun. “We might have bumped out the dining room a bit more, to accommodate our dinner parties and entertaining,” Hennessy says. She adds that the couple could use a few more feet in the laundry area, as well. “But these are little things,” Hennessy says.

“We also built this house for aging in place,” Palmer adds. “We’ve cared for elderly parents, so we’re aware of how our home needs to accommodate us in the future. For instance, there’s only one step up into the house. The bedrooms and baths are on one level. When we get to the point where we can’t walk to the mailbox, that’s when we’ll know it’s time to move.”