Page 21 - Green Builder Sept-Oct 2019 Issue

Annual Building Science Roundup 2020 A GRAND SYNERGY

wheelchair height, designing the kitchen and master
baths with roll-under sinks and counter tops, installing
a wheelchair-friendly shower, adjusting the height of
the electrical outlets and switches, relocating the electri-
cal box from the basement to the main floor, and mov-
ing the solar inverters from the basement to the garage
for accessibility. Other changes included designing zero-
entry thresholds for the front door and garage entrance
to the home, and installing a wheelchair-accessible path
to the basement entrance.
COURTESY OF HIGH PERFORMANCE HOMES neered the wall system to accommodate SIPs and other
To improve energy efficiency, DeGrandchamp re-engi-
insulation improvements, moved a set of outside stairs
that led to a room above the garage into conditioned
space, and added insulation under the basement slab.

maximize beneficial solar gain through the oversized
Top side. Highly efficient photovoltaic shingles blend in and help the home achieve a Home He also adjusted the home’s orientation on the site to
south-facing windows. The eaves were extended to
Energy Rating System (HERS) score of 35.
minimize overheating from high summer sun. GB
The ground-source heat pump also helps provide domestic hot
water via a desuperheater. The unit supplies hot water to a 55-gallon
storage tank plus a 0.91-energy-factor (EF) 55-gallon electric water KEY FEATURES
heater. A push-button-activated hot water recirculation pump and
low-flow fixtures help reduce hot water usage. DOE ZERO ENERGY READY HOME PATH: Performance.
The highly efficient home achieves a Home Energy Rating System WALLS: 6.5-inch R-23 Structural Insulated Panels (SIPs); house wrap;
(HERS) score of 35, far below the 80 to 100 of typical code con- stone and vinyl siding; 4.5-inch SIPs; one-inch closed-cell spray foam
struction. With the addition of a 5.94-kW solar system, the HERS plus R-19 batt at rim joists. All joints caulked.
score drops to 14 and annual energy bills drop from an estimated ROOF: Asphalt shingles, 15-pound felt; all eaves, gables and valleys
$1,290 per year to $585 per year, or $49 per month. To minimize have ice-and-water shield; kick-out flashing; five-inch sidewall flashing.
the visual impact of the roof-mounted photovoltaic (PV) array, the ATTIC: Vented attic, one-inch closed-cell foam sprayed on ceiling
builder selected PV shingles rather than panels. The shingles are deck plus R-49 blown fiberglass equals R-56 total.
similar in dimension to roofing shingles and actually take the place FOUNDATION: Basement of R-21.3 insulated concrete panel walls;
of some of them, for a profile that blends in. R-10 under slab.
WINDOWS: Double-pane, single-hung, low-e, argon-filled, U equals
ADJUSTMENTS FOR AGING IN PLACE 0.24, SHGC equals 0.17.
One of the unique aspects of the project for DeGrandchamp was the AIR SEALING: 1.1 ACH 50.
design. The home owners, one of whom is a Realtor, wanted it to look VENTILATION: Controlled smart switch venting system that calculates
good and be very energy efficient. It also needed to be handicapped makeup air; fresh air intake; timered exhaust.
accessible, as Dan is wheelchair bound. The homeowners already HVAC: Ground-source heat pump, 5.3 COP, 24.4 EER, 27.4 SEER;
owned the land and had plans drawn by an architect when they mastic-sealed ducts.
contacted DeGrandchamp. “Once we were contracted to build the HOT WATER: 55-gallon desuperheater, +0.91 EF 55-gallon electric
home, we made engineering changes to accommodate the [DOE Zero tank water heater. Push button recirculation pump.
Energy Ready Home] principles, plus make the home accessible for LIGHTING: 100 percent LED or CFL; all Energy Star fixtures.
®
the handicapped homeowner,” DeGrandchamp says.
®
To facilitate the design process, DeGrandchamp set up three for- APPLIANCES: All Energy Star .
mal meetings with the homeowners, in addition to many informal SOLAR: 5.94-kW PV system.
meetings. “To improve accessibility and to keep the home as energy WATER CONSERVATION: Low-flow fixtures; recirculation pump.
efficient as possible, we wanted to make sure we were not missing Native landscaping.
out on any detail that could improve the homeowner’s ease and ENERGY MANAGEMENT SYSTEM: Energy management system.
convenience when living and working in his home,” he notes. OTHER: Low- or no-VOC products; motion-sensor garage exhaust
Among the changes DeGrandchamp made to improve accessibility fan; ADA accessible.
were selecting and installing appliances that could be accessed from

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