Woolman Passive House
Passive House,
Zero Net Energy Home
TYPE: New Construction, Certified Passive House through PHIUS+, Zero Net Energy (ZNE)
SIZE: 3040 SF
LOCATION: Nevada City Area, Northern California
DATE: 2017
DESIGNER: Mela Breen & Jeff Adams (ADB alumnus) | Atmosphere Design Build
CONTRACTOR: Atmosphere Design Build
STRUCTURAL ENGINEER: Mark Jokerst, SE
MECHANICAL: Balance Point Home Performance
The Woolman Passive House sits on a parcel of land neighboring a long standing Northern California Quaker education and retreat center (that has since been sold to CHIRP, California Heritage Indigenous Research Project, for the return of land to the Nevada City Rancheria Nisenan Tribe).
The owner’s, Doug and Dorothy, who are Quakers and retired from nearly two decades with the Center, embarked on the project of building their “dream home” with the intent of embodying their values of peace, justice, and sustainability in a home that could serve as a model of sustainable living and community commitment.
The owner’s discovered the Passive House Standard, the world’s leading standard in energy efficient construction and were drawn to the ethics of efficiency, utility, comfort, and health that a home designed to meet the Passive House Standard could offer. The Woolman Passive House is also an expression of a commitment to the idea of simplicity in form and finish – something rooted in the Quaker notion of “plainness”, were un-adornment and sincerity have a long history and where the notion of “simplicity” has taken on a meaning of “stewardship,” “right sharing,” and “walking gently over the earth.”
As a son of the Midwest, a basement was a deeply rooted desire for Doug – and the location of the house and floor plan are driven by the desire to have a home anchored and tied to the earth. The house is three stories. The owner’s view the house as layers of community. The main level of the house is designed to allow for aging in place, with a large open living room and a deep sheltering covered porch that can accommodate “meeting” for their community. The second floor is for guests- visiting children, grandchildren, Quakers passing through, and provides a cozy perch to view the distant river canyon and local rolling hills. The basement anchors the house and is for creative endeavors and helping hands (should there be a need for someone to ever share the space with the owners as they age).
High Performance Highlights
Insulation
The complexity of the design, with its cantilevers and steel deck foundation, require a heightened attention to the air sealing and insulation details. The super insulated, air-tight building envelope is wrapped in exterior Rockwool insulation, all the connections between interior and exterior structural members are meticulously detailed to avoid thermal bridges, and triple pane European windows and doors are used to maximize light, comfort, and performance.
Climate Control
A CO2 heat pump water heater provides the most efficient domestic hot water delivery. Balanced heat recovery ventilation offers high indoor air quality and uniform temperature distribution. Indoor climate control is provided by a single ductless mini splits.
Energy
A 6.5 kw roof-mounted photovoltaic system, paired with two Tesla Powerwall backup batteries, offsets the home’s energy usage (including the charging of an electric car) – creating a zero net energy building.
"Atmosphere Design Build shepherded the creation of our Net Zero home with a remarkable blend of creativity and knowledge. In addition to her deep commitment to sustainability, Mela brought consummate artistry and down to earth practicality to every aspect of the design. Dave is a certified Passive House builder and brought a wealth of knowledge and a great spirit to all aspects of managing the construction of our house. The home that they produced not only achieves incredible energy efficiency, but provides us with a beautiful, healthy abode, that is remarkably easy to live in."
-Dorothy Henderson