“Kivi Mäki” Passive House
About this Project
This mountain contemporary home in Durango designed by Courtney King Studios was built to be 92% more efficient than a typical home. The 7.2 Kilowatts of high efficiency solar panels that cover the entire third story south facing roof will produce enough power to run the home and charge an electric vehicle. Passive house design principles of airtight thermal bridge free construction, gratuitous insulation, thermally superior doors and windows, and controlled ventilation allowed the home to earn a HERS Index Score of 8. The homes exterior is virtually fire proof with 22 Gauge metal siding, metal standing seam roofing, Shoi Sugi Ban Charred wood siding, and stucco.
Passive Home Design Principles:
The entire exterior envelope of the house was covered with two coats of a liquid applied, air and moisture barrier. This barrier helps to protect the wood structure, creates better protection at exterior penetrations, and seals all of the gaps in the framing from air and moisture intrusion. We have found this application to have superior durability and performance versus other applications where gaps are sealed with a peel and stick product that depends on adhesion with glues over time. The subfloor was also sealed at all joints prior to pouring the interior finished concrete floors.
The rim joists on the exterior edge of a home in the crawlspace are a notorious area for air infiltration on a home. These areas were insulated with a continuous 3” layer of closed cell spray foam with a high R value per inch and air sealing qualities. Closed cell foam was also used at the vaulted ceiling and the attic above the drywall layer to create an airtight seal at the ceiling level of the home.
Windows and Doors:
Local artisan Joel Schiavone created a beautiful custom entry door that also performs with double insulated weather-stripping and precise European hardware. Triple pane uber efficient windows that are Passive Haus (European standard) and PHIUS(Passive House Institute of the US) certified were used throughout. Care was taken to place operable windows properly to allow for the fresh Colorado air to flow naturally throughout the home. Glazing on the south aspect of the home outweighs the rest of the home to maximize passive solar gains in the winter. Proper shading and orientation avoids any overheating issues in the summer months.
Thermal bridges were virtually eliminated by adding a 2 ½” layer of EPS insulation around the entire exterior of the framed structure. In vaulted ceiling and floor areas engineered I joists with very low thermal transference rates were used.
Blown in fiberglass insulation was used at all exterior walls, floors, and ceilings. With a blown in installation electrical and plumbing within the walls can be surrounded better than any Batt type of installation and allows for a higher R-value.
Controlled filtered ventilation is a requirement in such a tightly built home. We used a Zhender ERV unit due to its low energy usage and superior energy recovery efficiency. The system constantly is bringing fresh filtered air into the living areas of the home and pulling stale air out. This is done in a controlled balanced way with air being drawn from the bathrooms, mechanical room, and kitchen and being supplied to the bedrooms and living room in nondescript ceiling or wall registers. This system was especially helpful this summer where smoke from regional fires was present for long periods of time.
The home boasts 7.2 Kilowatts of photovoltaic energy production. Nestled amongst the tall pines in Edgemont Highlands it seemed a difficult task to harness a large amount of solar energy. The home however was designed not only to be unobtrusive to the existing landscape but also to raise as high as possible the south facing roof line above most of those tall pines. We were able to accommodate on that roof as many solar panels as the local electrical supplier would allow. The result is that the entire roof that faces south was covered with high efficiency panels. By building an extremely efficient home the 7.2 Kilowatts should cover 120% of the energy usage needed for the homes heating, lighting, and cooking. This will leave energy enough without paying the power company to charge an electric vehicle as well.