Passive Houses, Simply Complicated
SALEM, Ore., February 12, 2010
Compared to other types of green homes, a passive house is like a ThermosTM bottle that breathes. Passive houses are super-insulated homes that use advanced ventilation systems to provide the homeowner with superior indoor air quality and balance the temperature inside the home. Passive houses are designed to minimize, and even eliminate other energy-reliant systems, resulting in minuscule energy bills. After considering the benefits associated with other types of green homes, for Sarah Evans and her husband, Stuart Rue, the decision to build a passive house was relatively easy.
The first step in the decision process occurred last spring when the couple purchased an empty lot just down the street from their current residence, a 1930s craftsman home, in the winter and before numerous upgrades, features all the cold, drafty, and outrageous utility bill charm typical of most houses of its era. Knowing what they wanted to avoid led to the next step of the process: the decision to build a green home. “We knew we wanted to do something good for the environment and save money on our energy bills,” says Evans.
The final decision to build a passive house came after Evans and Rue hired Blake Bilyeu of Bilyeu Homes as the general contractor/builder for the project. Bilyeu Homes has an impressive portfolio of Earth Advantage® and LEED® certified projects, and in addition to passive house certification, Bilyeu is also an Earth Advantage Sustainable Homes Professional (SHP) graduate. “Sarah and Stuart called me just before I began the passive house consultant training,” says Bilyeu. “They were very open minded about the whole project. I explained the differences between a passive house and other green homes, and they were very enthusiastic about the idea.” The passive house project was officially underway.
Passive houses require a significant amount of planning and computer modeling before construction can begin. Factors such as directional orientation, total window area, and information about the region’s climate are all necessary to ensure that the house can function properly. To help with the aesthetic design, renowned green architect Nathan Good was consulted. “We wanted our house to fit in with the surrounding neighborhood and Nathan really made that happen,” says Evans. Good helped meld the home seamlessly into the neighborhood with subtle nuances, including the tiered garages and the front porch.
Although passive house construction requires a different approach than other green homes, the only major construction challenge was presented by Evans and Rue. “We needed a dog door installed,” laughs Evans. Since passive houses depend on air sealing and insulation to be certified, having a permanent, uninsulated path to the outdoors could severely affect the homes performance. “I did a lot of research and found a dog door that passed a blower door test to the standards that were required,” says Bilyeu. Although other U.S. passive houses have dog doors built into exterior storm doors, this will be the only passive house in the United States with a permanent dog door.
As the construction process nears completion, the benefits of a passive house are already evident. “We went over to the house after the drywall was up and the builders had a small space heater in the garage,” recalls Evans. “We didn’t have any garage doors yet, and it was just as warm upstairs as it was next to the heater in the garage.” Being new to the performance of a passive house as well, Bilyeu investigated with a thermal imaging camera and determined that the temperature next to the heater was 72° F and the temperature upstairs, in the furthest closet from the garage, was 68° F. “And that was before the ventilation system was installed,” says Bilyeu. Since passive houses are designed to minimize heating and cooling systems, ventilation systems help maintain the home’s temperature balance and provide superior.
Life in a passive house will be different than in a traditional home. When asked whether there was anything that worried her about the change, Sarah replied, “It’s a little weird moving into a home without a furnace.” Instead of a furnace, the home will have an extremely efficient, mini-split heat pump system that is rated at 9,000 BTU/h. “It’s actually twice as much as this home will need,” says Bilyeu. When asked what about her new house excited her the most, Sarah replied, “My new front porch.” Some things will never go out of style.