Net Zero Homes

Hollis Net Positive Home

Hollis, New Hampshire

Layout: 4 bdrm, 2.5 bath, 2 floor, 3,197 sqft.
Climate: IECC 5A, cold
Category: Custom for Buyer

Key Features

Walls: 2x6, 24 in. o.c., total R-41: 5⁄8" drywall; 1-1⁄2" service cavity, vapor-open membrane, 5-1⁄2" dense-pack fiberglass in wall cavity, 1⁄2" CDX plywood, vapor-open WRB, 5" mineral wool board, 3⁄4" furring strips/drainage plane, cedar siding.
Roof: Truss gable roof, 5⁄8" CDX sheathing, self-adhered bituminous membrane over whole roof, fiberglass shingles; 22" raised heel trusses.
Attic: Vented attic with 18" R-38 blown fiberglass.
Foundation: Basement, 5⁄8" drywall, 2x4 24" o.c., vapor-open membrane, 1" Type IX closed-cell EPS, 10" concrete, self-adhered membrane, 5" mineral wool, dimple mat.
Windows: Triple-pane, low-e2, argon-filled, vinyl-framed, tilt-turn; U=0.15, SHGC=0.51.
Air Sealing: 0.60 ACH 50. Sub-slab poly and vapor-open wall and ceiling air barriers were taped together at seams. All penetrations sealed with tape and fluid-applied flashing.
Ventilation: ERV, 116 CFM, 44 Watt, SRE 83; separately ducted, MERV 13 filter, CO2 sensor.
HVAC: Ducted mini-split heat pump; 11 HSPF, 18 SEER, 3 indoor air handlers, 3 outdoor compressors. Rigid metal ducts, sealed and insulated, compact design, in conditioned space.
Hot Water: Heat pump water heater, 65 gallon, EF 3.85; in basement.
Lighting: 100% LED, large windows used throughout the home.
Appliances: ENERGY STAR refrigerator, dishwasher, clothes washer, primary water heater.
Solar: 9,75-kW of solar panels; installed on barn roof.
Water Conservation: EPA WaterSense certified whole house.
Energy Management System: PV software tracks production. Wi-Fi HVAC controls.
All materials Green Guard Gold Certified. No Redlist products were used.

Modeled Performance Data

HERS Index: without PV 26; with PV -7
Annual Energy Costs: without PV $1,650; with PV $200
Annual Energy Cost Savings: (versus typical new homes) without PV $4,850; with PV $6,500
Annual Energy Savings: without PV 8,800 kWh; with PV 27,750 kWh
Savings in the First 30 Years: without PV $19,750; with PV $264,250