Building Use: Detached single-family residence
Project Type: Passive house retrofit
Featured Image by Mark Peterson/Redux Retrofitting for a low carbon-emission future makes this a "futurefit" to an existing single-family residence we built in 1998. The Passive House Institute calls this an "EnerPHit." We started in 2009 and completed most envelope improvements by 2011. We are still finishing with equipment upgrades, most recently in 2017 with a Sanden environmentally-superior CO2 refrigerant heat pump water heater supplying 100% of both domestic hot water and 100% of our space heating. Already, we have cut our energy consumption by 45% from an average of 15,800 kWh/year to 8,200 kWh/year. And our space heating energy consumption by 70%. We saving approximately 7,000 kWh every year. We have disconnected 5 gas appliances and are now 100% powered by our local utility's 100% new renewable electric energy.
Location: | Portland, Oregon 97215 | |
Dwelling Units: | 1 | |
PH Calculation Protocol(s): | PHI | |
PH Modeling Software(s): | PHPP | |
Construction Cost: | $ 150,000 USD | |
Year Of Construction: | 2010 | |
Project Size | ||
Floor Area: | 1,903.0 ft2TFA | 176.8 m2TFA |
Performance | ||
Heating Degree Days: | 4,278 °F•day/yr | 2,376.7 °C•day/yr |
Cooling Degree Days: | 575 °F•day/yr | 319.4 °C•day/yr |
Annual heat demand: | 4.70 kBtu/yr•ft2TFA | 14.8 kWh/yr•m2TFA |
Heat load: | 2 Btu/hr•ft2TFA | 6.3 W/m2TFA |
Primary energy demand: | 26.31 kBtu/yr•ft2TFA | 83 kWh/yr•m2TFA |
Primary energy demand after on-site generation: | 28.10 kBtu/yr•ft2TFA | 88.6 kWh/yr•m2TFA |
Airtightness: | 0.75 ACH50 | |
Envelope | ||
Construction Type: | wood | |
Floor Assembly: | hardwood: 0.25" plywood: 1.24" expanded polystyrene between 2X10 joists: 9.25", 23 cm expanded polystyrene under 2X10 joists: 5", 12.7 cm U-value = 0,101 W/(m2K) | |
Wall Assembly: | GWB: 0.5" Cellulose densely-packed in 2x6 stud cavity of framing; 5.5", 14 cm Plywood structural sheathing & air barrier :0.5" Cellulose densely-packed in Larsen Trusses: 10", 25 cm Fiberboard: 0.5" Air space under wood lap siding: 0.38" U-value = 0,114 W/(m2K) | |
Roof Assembly: | GWB: 0.5" Fiberglas densely-packed: 5.5", 14 cm Cellulose loosely-packed: 20", 51 cm U-value = 0,064 W/(m2K) | |
Windows: | Alpen High-Performance Fiberglass frame Windows Model 925 urethane foam-filled pultruded low-profile fiberglass NFRC whole window value: Fixed: 0.14 Casement: 0.17 Two glass panes with two low-e films between them with krypton fills Ug-value = | |
Entry Doors: | Innotech tilt-turn with Cardinal triple-pane low-e glazing in Trocal non-plasticized hard PVC frames Ud-value = 1,76 W/(m2K) | |
Systems | ||
Ventilation system: | J.E. Storkair & ZehnderAmerica ComfoAir 350 PHI-certified HRV with ComfoTube and ZehnderAmerica and Seiho diffusers | |
Heating/Cooling system: | 2.5 kwh electric resistance coil in supply air ducts of ventilation system backing up Sanden CO2 refrigerant heat pump water heater emitting space heat via Runtal vertical radiator in main room (replaced high-efficiency (92%) condensing gas furnace) | |
Domestic hot water system: | Sanden CO2 refrigerant heat pump water heater (replaced High-efficiency (93%) Condensing Gas within tank) | |
Renewables: | Offsite via purchase of local utility's 100% new renewable electricity purchase plan (does not include pre-2000 hydro). | |
Other green building systems: | 1,000-gallon concrete cistern below garage stores precipitation to supply 90% of irrigation low-flow fixtures in lavatories (0.5 gpm), showers (1.5 gpm) and kitchen (1.75 gpm) vegetative summer shading produces grapes, raisins, and kiwis natural linole | |
Team | ||
Passive House Consultant: | Tad Everhart and Hayden Robinson | |
Passive House Consultant Certification: | PHI | |
Architect: | Chris Nestlerode | |
Structural Engineer: | Mark Butler, Butler Engineering | |
Mechanical Engineer: | Peter Reppe, Mike LeBeu, Barry Stephens and Matt Groves of ZehnderAmerica | |
Contractor: | Garth Everhart | |
Comments | ||
Additional Information: | Our home is now all-electric; 90% of pre-retrofit energy was methane gas 100% of electricity is provided by local electric company's elective clean energy program requiring utility to purchase enough electrical generation from new renewable sources to supply our demand (in excess of mandatory renewable energy portfolio purchase requirements) 95+% reuse of building materials removed during refurbishment Energy monitoring courtesy of Portland State University Green Building Research Laboratory and Washington State University Extension Energy Program |