"The main goal of this retrofit project was to take a home that was built in 1952 and get it ready for the next 100 years."


Key Features

  • Walls: Double wall retrofit, R-23 total: existing 2x4 16" o.c. with fiberglass batts, replaced drywall with CDX plywood, horizontal 2x3s 24" o.c. and R-11 fiberglass batts and drywall. On exterior, topped old 1x sheathing with self-adhered WRB, metal siding.
  • Roof: Gable roof: Covered existing 1x sheathing with membrane taped, new 9.5" I joists, OSB, self-adhering membrane; composite shingles.
  • Attic: Vented vaulted ceilings: 5.5" + 8.5" R-54 fiberglass batts.
  • Foundation: Vented crawl space: batt insulation in 2x8 floor. Topped existing subfloor with ½" EPS, radiant floor tubing, 2" poured concrete slab.
  • Windows: Thin-film triple-pane, argon-filled, low-e, fiberglass frame; U=0.18, SHGC=0.30.
  • Air Sealing: 1.34 ACH50, all edges and holes sealed with joint sealer, vapor air barrier with sealed edges on existing roof deck, self-adhered WRB over existing sheathing.
  • Ventilation: HRV, MERV 13 filters, separately ducted in conditioned attic.
  • HVAC: Air-to-water C02 heat pump for hot water and radiant floor heating. 5.2 COP.
  • Hot Water: Air-to-water CO2 heat pump for hot water and radiant heat. 119-gal, 3.00 EF.
  • Lighting: 100% LED.
  • Appliances: ENERGY STAR refrigerator, dishwasher, clothes washer, heat pump dryer.
  • Solar: 13.44 kW, 42 320-W rooftop panels, passive solar design.
  • Water Conservation: EPA WaterSense showerhead, smart recirculation pump.
  • Energy Management System: Smart thermostats.
  • Other: EV charging; accessible floorplan, shower; low-VOC paints, finishes.

Building Specifications

Conditioned Area 2,277 ft2
Bedrooms 3
Bathrooms 2.5
Stories 1
Climate Zone 4C
Completion Date October 2020

Modeled Performance

  With PV No PV
HERS Index -41 43
Annual Energy Cost ($550.00) $700.00
Annual Energy Cost Savings $2,000.00 $800.00
Annual Energy Savings 25,200 kWh 9,700 kWh
First 30 Years Savings $81,900.00 $31,400.00