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Project Description:
Completed in Septemeber, 2015, Our Zero Energy home is the perfect example of building an affordable, small footprint home in Bend, Oregon. The small narrow lot size was chosen due to its rocky yet unobstructed southern exposed south slope. Our building design takes advantage of this unique lot at every angle and built above the rock for full solar advantage. Due to our home's west side summer sun exposure, a contributor to overheating in the summer, we chose to have very few windows facing west. Instead, we placed numerous large windows on our south-facing wall. Double wall construction, super tight air sealing and 4.3kw of PV takes care of our year-round energy needs. We also chose our building site due to its unique proximity to the core markets and venues in and around downtown Bend, a definite(high) walkability score value! Our home was featured in Central Oregon's Green Homes Tour 2015 and continues to see an increased interest in our community since then. It is our hope that the features of our home, as well as the small size and zero energy benefits, will strengthen the market for zero energy homes, especially those looking for something affordable, and yet a bit bigger than a tiny home.
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Other Awards:
Earth Advantage Platinum
Energy Performance Score, EPS 4
Energy Trust of Oregon
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Owner-Occupied
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Site description:
We call our home The Perch in order to capture the feel of being a bit higher up off the ground than our neighbors. Our site literally captures the sunlight year around. No permanent irrigation is installed. We have designed a vegetable garden built using the water savings SIP method. The remainder of the outdoor space is zero-water landscape with many native species.
Above grade wall assembly:
The double-stud, wood-frame wall was constructed of 2x4s to create a 10-inch cavity. Insulation is fiberglass blow-in blanket. The primary air barrier is the external OSB structural sheathing, which has been glued to the outer face of the wall framing. Additional air sealing was performed as needed for gaps and penetrations. All electrical boxes were coated with a thick layer of water-based duct mastic to seal wire penetrations and unused knockouts. The deep window and door openings were finished on the interior with drywall wraps instead of trim.
Cathedral ceiling assembly:
The roof is framed with 16-inch I-joists and filled with fiberglass blow-in blanket insulation. Ventilation trays maintain the code-required ventilation space below the roof sheathing between continuous soffit and ridge vents. To minimize air leakage and water vapor migration, a conscious effort was made to minimize ceiling penetrations. Only four electrical boxes were mounted in the vaulted ceilings, two smoke/CO2 dectectors and two ceiling fan boxes. All plumbing vents were connected into a single 3-inch vent through the roof. The kitchen drain uses an air admittance valve instead of a standard vent.
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Published References:
Green Energy Homes Tour, Bend Oregon Site #3 : https://www.theenergychallenge.org/about/bec-week-green-tour/2015touro
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Scope Description:
The home captures ample daylight on a small narrow 25 feet of south-facing wall. The resulting design approach might be called 20th Century Solar, with almost all the windows along the narrow south wall. Our large, guest friendly loft offers to share light from its clerestory windows to the back bedroom/study.
Smaller Energy Star appliances occupy less space in the floor plan and allow additional kitchen storage and work areas. The two-burner induction cooktop will serve virtually all cooking needs both indoor and out. Our large shaded 21x14' south facing deck is the summer kitchen with views of the cascades.
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To maintain low construction cost, we wanted to use materials and methods that were familiar to most trades.
Window Description:
More than 50% of the home's windows face south to capture solar heat. No interior thermal mass was installed. The Milgard Styleline windows are vinyl-framed double-glazed. These windows use argon fill and low-e coating on two glazing surfaces to acheive a relatively low rate of heat loss for a double-glazed product. Because of the "sun tempered" approach, the south-facing windows would normally be high SHGC. However, cost considerations lead to the choice of a more standard product rather than a special order. As it turns out, the large solar apeture provides considerable winter gain in spite of the low SHGC. Heat loss in winter is reduced with tight-fitting, double-cellular window shade. Exterior summer shading virtually eliminates summer overheating.
Door Description:
The main entry door faces south. It is a Therma Tru, insulated fiberglass unit with a full, glass lite and a three-point latch. Other doors are steel insulated units.