The Ashtree Residence will be Idaho’s first PHIUS+ Certified Passive House. The Passive House standard is a performance-based set of principles that can be optimized to reduce energy consumption by up to 75% over a code-built home. The fundamental design strategy in a Passive House is the investment in a high-quality, resilient building envelope. The envelope of the Ashtree Passive House will have super-insulated walls and highly insulating triple-pane windows. This insulation not only reduces heat loss but also eliminates drafts and cold spots to provide unprecedented thermal comfort.
The building will be carefully sealed to eliminate any air leakage and reduce heat loss. A balanced heat recovery ventilation system will provide the house with continuous fresh air. This ventilation system exchanges the entire volume of air in the house every three hours thus providing exceptional air quality.
Since the Ashtree Passive House is an optimized system of passive elements (insulation, windows, air-tight construction), its demand for heating and cooling energy is very low. The small amount of heating and cooling that will be required can be provided by simple, highly efficient mechanical equipment. Heating and cooling will come from two ductless heat pumps while a heat pump water heater will provide domestic hot water. The significant reductions that are a product of Passive House principles allow for very low monthly operating costs and short payback periods on initial investments. An understanding of building science and the third-party quality assurance program required by the PHIUS+ certification ensure a durable, long-lasting building.
The Passive House standard also places a limit on the total amount of energy consumed by the house. To meet this target limit the Ashtree Passive House will include highly efficient appliances and lighting. The project will also include a monitoring system that will record the energy used by mechanical equipment and appliances. This information will provide feedback to the residents and will serve as a proof of concept of Passive House principles.
The Ashtree Passive House will qualify for the U.S. Department of Energy’s Zero Energy Ready Home program. While the project will not initially include any onsite renewable energy, the necessary infrastructure will be provided to make for the quick addition of future photovoltaic panels. Enerform firmly believes that the Passive House principles, and the associated reduction in energy demand, should be the foundation for any “net-zero” project.
Through its design aesthetics and high performance, the Ashtree Passive House will serve as a benchmark in the Boise area for future architects, builders and developers interested in reducing energy consumption while providing beauty, comfort, and durability.
Franklin St. Remodel
Enerform was given the opportunity to transform the basement of a 1940’s home into a separate dwelling unit. The original basement consisted of a family room, two bedrooms, a half-bath, and a utility/storage room. The new program called for the addition of a kitchen, a full bathroom, storage closets, an office space and a laundry room.
The existing basement was gutted and new plumbing and electrical service was updated throughout. New historically appropriate wood windows flood the basement space with light and instill a sense of openness and connection to the outside.
To eliminate the loss of headroom from the original heating ducts, the existing furnace and ductwork were removed and replaced with efficient ductless heat pumps. Three Fujitsu mini-split units were installed in the basement unit and an additional three were retrofitted in the existing upstairs unit. The combination of newly insulated basement walls and highly efficient heating and cooling equipment will significantly lower energy use and monthly bills.
The overall design aesthetic is a blend of contemporary styling, warm materials and traditional elements fitting of a North End Boise residence. Timeless white kitchen cabinets were capped with cherry butcher-block countertops. A dark, rough-hewn hardwood floor contrasts the contemporary kitchen appliances and bathroom fixtures.
Foothills Passive House
Situated on a south-facing lot with views of Boise’s iconic Table Rock, the Foothills Passive House nestles into the sloping terrain. When viewed from the street the structure appears to be a modest reinterpretation of a classic ranch home. But on the south side a second story emerges in the form of a daylight basement with a large covered patio carved from the monolithic volume. Large triple-pane windows and sliding doors open the upper level kitchen and living space to views of Table Rock and Boise below. The grey vertical cedar cladding creates a rich texture that gives life to the simple, clean form. Precise detailing combined with exacting principles of building science come together to make the Foothills Passive house an elegant, highly energy efficient home.
Completed 2014 Noville, Switzerland In collaboration with RB&MC
The design of the Noville Apartments emerged from a complex interaction of design constraints. The owner’s goal was to create a residence for himself and add as many secondary units as possible within the zoning restrictions of the small town of Noville. Strict height limitations restricted the project to two and half stories. Parking was originally envisioned to be located under the building but a high water table and lack of space for a ramp made this impractical.
Because underground parking was not possible, the first level of the building is dedicated to parking, with a private four-car garage for the owner and two two-car garage for the other apartments. Two generous apartments occupy the second level with large balconies giving breathtaking views of the Rhone Valley. The top level houses the owner’s apartment and a one-bedroom apartment.
A common central corridor provides access to stairs and the elevator. The owner requested that the common elevator provide private access from his garage directly into his apartment. This was achieved by carefully arranging access to the elevator and making use of a dual-door carriage.
Providing light to the upper level proved to be challenging because of a rule restricting roof dormers to 20% of the façade width. Special permission was granted to cut into the roof to provide a walk-out balcony for the owner’s apartment.
The building was structurally challenging due to large cantilevers and offset bearing lines. The structure is a combination of reinforced concrete and masonry. Expanded polystyrene provides a continuous layer of insulation that is coated with stucco. A central boiler provides hot water for radiant heating throughout the building.
Rhone Valley Residences
In progress 2012-2014 Bex, Switzerland In collaboration with RB&MC
The Rhone Valley Residences are situated on a parcel currently occupied by the landowner’s single family home. The project calls for the demolition of the home and the construction of two buildings housing nine apartments. The owner will then move into one of the new units.
Zoning regulations restrict the building heights to three stories. It is also necessary to split the volumes into two separate buildings and maintain a generous open space between them. A combination of underground and above ground parking is necessary to create the required number of parking spaces.
The larger building contains three three-bedroom apartments and three two-bedroom apartments. The smaller building contains three three-bedroom apartments. Vertical circulation in both buildings is provided by a common stairwell and elevator. The basement of each building houses mechanical rooms, storage rooms for each apartment, common storage areas and a civil protection bunker. The two buildings are linked by an underground parking garage.
Large balconies provide each apartment with private outdoor space and spectacular views of the Alps to the southeast. The roof of each building serves as a common gathering area for the residences. Solar hot water panels reduce the demand on the central boiler for heating and domestic hot water. Colorful sliding shutters provide sun protection and create a continually changing facade.
Kimball Art Center
Competition Entry 2009 Park City, UT
As an entry for a preliminary design competition for the expansion of the Kimball Art Center, this project proposes a new three-story volume adjacent to the existing building. The addition would house a lobby, café, galleries and classroom space. The design calls for the closure of Heber Avenue to make way for a sunken courtyard along the north façade of the existing building.
The glass façade of the addition presents a pixelated pattern of mirrors and transparency that absorbs, reinterprets and then projects the surrounding context.
Several more iterations of the design competition have since taken place, with numerous world-class architecture firms taking part. Their entries can be seen here.