For Sam Rodell, principal at Kirkwood Rodell Architects PS, of Spokane, a popular German passive-house design method could be the next big thing in architecture, if it continues to gain ground in the U.S.

Rodell, who has had his own architecture firm since 1984, only recently started working on that type of design. Rodell says he is one of 300 certified passive-house consultants in the country after he became certified in Seattle last year by the Passive House Institute US, a nonprofit based in Illinois.

Passive-house design focuses on creating a well-insulated, air-tight building that's maintained temperature-wise through solar heat, and by people and objects within the building that give off heat, such as a water heater. Passive-house design can be used for commercial and multifamily buildings as well as for home construction, Rodell says.

He currently is working on his first projects utilizing the passive-house methodology—a 1,400-square-foot house in Elk and a 20,000-square-foot boarding home in Spokane Valley. Those projects will use a combination of different insulation materials to keep as much heat or cool air within the building as possible, he says. The basement of the home in Elk will use a layer of foam around the foundation that will help keep energy within the house from escaping, he says.

The design method has been slowly gaining steam here in the U.S. over the past few years, but it's been popular in Germany for about 15 years and has become "mainstream" there, he says.

Rodell says industry standards show a passive-house design will cost about 10 percent more to construct than structures built to meet standard building codes, but the mechanical costs to install typical heating, ventilation, and air-conditioning units are eliminated. Instead, passive-house design relies on what's known as an energy recovery ventilator paired with a high-performance filtration system to circulate fresh air while eliminating stale air.

"Most of the energy used in the U.S. is burned by buildings, and most of that is heating and cooling," Rodell says. "It's the biggest piece of the pie."

He says the higher building cost is a point of resistance for some clients. Although according to the Passive House Institute US, once constructed, a passive-house building uses only about 10 percent of the energy consumption of a typical building annually.

He says although passive-house design does mostly use mainstream building materials, specially designed products such as the windows still need to be imported from Europe.

"One of the reasons these products aren't readily available is (building supply companies) don't see a market here, and that's going to change," Rodell asserts, adding that he believes the federal government is becoming interested in the design method.

In the U.S., passive-house design is found mostly in New England cities and in the Pacific Northwest, although it also is used in other areas throughout the U.S., he says. He says the Spokane climate, with fluctuating temperatures throughout the year, makes it an ideal market for passive-house design.

"We do very rigorous computer modeling of the architecture to design these, and part of it has to do with the exterior climate," Rodell says, adding that factors such as humidity levels inside and outside can affect the overall design of a building.

Modeling also takes into account the number of people planning on living in the building, and the location of household elements that produce moisture, such as a shower or cooking range, which generates heat. The computer software has the ability to show how each component of the structure hinders or helps the overall energy performance of the house, he says.

"You'll design the project to be a good container for heat, but in the summer, you have to account for cooling," Rodell says.

He says with so many factors being considered, what may be regarded as an optimal passive-house design in one location might not work in another.

"If I'm doing a passive house in Phoenix, then my challenge will be cooling," Rodell says, adding that even environmental data for locations seemingly near each other differ, such as Spokane Valley and Elk, Wash., the locations of the two projects he's working on currently.

Rodell says the passive-house design methodology is one more development in the design industry that architects weren't thinking about 10 years ago. Asked about why he chose to become certified in passive-house design, he says, "It's the right thing to do."

Rodell operates the architectural firm with partner Calla Kirkwood out of a 350-square-foot office in Steam Plant Square downtown, and has three full-time and two part-time employees. He says that although he's a strong proponent of passive-house design, it's not a method that has taken over the firm.

"Clients here, we don't push it at them, but we inform them," Rodell says.

Passive-house designs sometimes can be paired with an alternative energy source, such as wind, solar, or geothermal, to augment the energy recovery ventilator and filtration system, he says.

However he contends when such a design is paired with an alternative energy source, it can produce more energy than it uses at various points throughout the year.

"What I'm seeing in practice here is clients are enthused about it because the economics are compelling," Rodell says. "It's a win-win situation when building green means saving money."

He says another benefit of a passive-house design is air quality.

"The interior air quality will usually be higher than outside," Rodell says, because of the filtration system used to ventilate the building. He says that alone can be a big selling point for clients, adding the ventilation system is circulating new air constantly. He claims the system has about a 90 percent efficiency of not letting the heat out of or cold air into a house.

Passive-house certification is a combination of training and tests that can take between a month and a couple years, depending on how intensively an architect pursues the certification, he says.

Kirkwood Rodell Architects designs commercial, institutional, and high-end residential projects. Rodell designed an approximately 8,000-square-foot office building at 25 W Cataldo in 2006. The firm also designed the Northpointe Retirement Community, now Brookdale Place NorthPointe , a 110-unit retirement facility located at1110 E. Westview Court in the late 1990s.