Page 30 - Green Builder Magazine Sept-Oct 2021

Power packed. A highly insulated shell and
rooftop solar result in a house that is “energy
Key Features positive,” producing enough power to run the
home and charge a future electric vehicle.
COURTESY OF ZIGZAG MOUNTAIN ART
AIR SEALING: 0.47 ACH, all SIP seams caulked
and taped; aerosol whole-house sealant.

APPLIANCES: ENERGY STAR refrigerator,
dishwasher, clothes washer and clothes dryer.

ATTIC: No attic.

ENERGY MANAGEMENT SYSTEM: Automated,
internet and voice-controlled lighting, blinds
and HVAC; HRV triggered by CO2 and humidity
sensors.

FOUNDATION: 4-inch R-20 rigid foam under
slab, 5-inch R-24.3 ICF stem wall.

HOT WATER: Combi uses space heating air-to-
water heat pump, 3.93 COP; 80-gallon hot water
storage tank and 40-gallon buffer tank to prevent
short cycling.

HVAC: Air-to-water heat pump, 3.92 COP
(heat), 6.75 COP (cool), 23.02 EER. Uses HRV
ducts to distribute hot and cold air, plus radiant
floor.

LIGHTING: 100 percent LED; day lighting; measured and precision cut to the house of acrylic are sprayed into the rooms
clerestory windows; automated and remote plan dimensions for doors, windows while the home is pressurized with a
controls. and wall sections. Almost no framing blower door. The pressurized air carries
is required—just caulking and taping tiny acrylic particles, which adhere to and
ROOF: SIP roof: 12.25-inch R-59 graphite SIPs, seams, installing windows and doors, seal off any leaks. In this case, the home
membrane, standing seam metal roof. house wrap and fiber cement lap siding. was sealed to 0.47 air changes per hour
TC Legend uses insulated splines to at 50 Pascals (ACH 50), tighter than the
SOLAR: 12.4 kilowatt, 40 310-watt panels; roof connect the panels. Thicker 12.25-inch, 0.60 ACH 50 required by Passive House
sized for 80-plus panels; wired for future battery. R-59 SIPs are used to construct the roof. Institute U.S.A.
The panels are covered with a three-layer Triple-pane, argon-filled vinyl-framed
VENTILATION: HRV, ducted; MERV 13 filters; durable breathable membrane underlay- windows complete the thermal envelope.
humidity and CO2 sensored; boost setting. ment and topped with a 24-gauge stand- The windows have three low-emissivity
ing-seam metal roof. coatings to slow heat transfer. The case-
WALLS: SIPs, R-29 total: 6.5-inch R-29 graphite The rigidity of the two adhered layers of ment style windows have a U-Factor of
SIPs, house wrap, fiber cement siding. OSB provides exceptional shear strength 0.16 and the fixed windows have a U-Fac-
for the walls and roof, making SIPs an tor of 0.14. Most windows are south facing
WATER CONSERVATION: EPA WaterSense excellent choice for structural stability to allow sunlight to warm up the exposed
fixtures; central manifold plumbing with PEX in areas prone to high winds and earth- sealed concrete floors for intentional pas-
pipe; drought-resistant landscaping; rainwater quakes, such as in western Washington sive solar heat gain in the winter.
collected to central sump for irrigation. state. Because of the structural strength A wraparound porch and overhangs
of the walls and roof, no roof trusses help to limit unwanted solar heat gain
WINDOWS: Triple-pane, argon-filled, low-e3, are needed and all interior walls can be in the summer. Automated blinds on the
vinyl-frame, U=0.14 fixed, U=0.16 casement, non-load bearing, providing for cathedral south and east windows can be scheduled
SHGC=0.33 to 0.44 tuned to direction; ceilings and greater design flexibility for through the home automation system to
automated window blinds. interior spaces. help control heat gain, heat losses, day-
Although SIPs are known to provide light and views. The large south- and
OTHER: Electric vehicle charging; no-VOC draft-free construction, the home was east-facing windows and clerestory
paint; GREENGUARD Gold SIPs; Americans with further air sealed by using the AeroBar- south-facing windows bring daylight into
Disabilities Act (ADA) features. rier process, in which atomized particles the main level as well as into the upper

28 GREEN BUILDER September/October 2021 www.greenbuildermedia.com