Image Credit: credit: Tomasz Biernacki, Pechara Studio Inc. (image 1), Solar Knights Construction (all other images) A view of the O’Neill property from the street, before work began. Concrete from the demolished patio was used for landscaping walls. The remodel included a 400-sq.-ft. addition. The house acquired a U shape as a result of the renovation, requiring a relatively intricate system of HVAC duct runs. The retrofit applied the Pressure-Equalized Rain-Screen Insulated Structure Technique, with insulation and barriers such as Aerogel Spaceloft, InsulFoam IX expanded polystyrene, Insulfoam R-Tech IV rigid foam, Optima blow-in insulation, Grace Ice & Water Shield. The first layer of 2.5-in. expanded polystyrene. The second layer of expanded polystyrene: 1.25-in. R-Tec, with a radiant barrier at the window buck. Optiwin 3 Wood window frame prepped for installation.
UPDATED on March 30, 2011 with a new link at the bottom of the page to a video of the project.
The messy, retrofitting part is over. Now it’s time to track the performance of Cathy O’Neill’s 1960s-era home in Sonoma, California, which was expanded and renovated to the Passivhaus standard.
Last time we checked in on the project, in late March, builder Rick Milburn, of Solar Knights Construction in nearby Napa, was leading his team through the particulars of insulating and sealing about 40% of the existing envelope and a 400-sq.-ft. extension using the Pressure-Equalized Rain-Screen Insulated Structure Technique, with insulation and barriers that include Aerogel Spaceloft, InsulFoam IX expanded polystyrene, Insulfoam R-Tech IV rigid foam, Optima blow-in insulation, Grace Ice & Water Shield; Stego Wrap, and Protecto Wrap building tape.
The aim was to bring the floors to between R-12 and R-20, the roof to R-74, and the exterior walls to R-31, and add Optiwin 3 Wood triple-glazed windows and doors. The HVAC package includes an UltimateAir RecoupAerator energy recovery ventilator that, Milburn recently told Contractor magazine, likely will be used about 10 or 12 days a year, and only at about 30% capacity. The house originally featured 2,400 sq. ft. of interior space and radiant heated floors that were supplemented by electric baseboard heaters.
Savoring the results
All the planning and effort finally found their intended target. On July 20, Solar Knights announced that the house had earned certification from Passive House Institute US, making it the first residential retrofit in the United States to do so. Having made the unusual journey from retrofit candidate to Passivhaus performer, the house also will be monitored by the Department of Energy’s Lawrence Berkeley National Laboratory, and has been selected as a prototype by the DOE’s Building America Program.
For Milburn, the project was both demanding and enormously rewarding. “I will say that this is the hardest house I have ever built, but everything from here on out will be easy,” he told Contractor. “In the climate that I work in, there is no reason that all new construction shouldn’t be built to the Passivhaus standard. It’s just not that hard.”
To see a video tour of the project, click here.