Oak Park architect Tom Bassett-Dilley and builder Brandon Weiss of Geneva’s Evolutionary Home Builders have combined forces again to build a passive house in the near western suburbs. Like the first Chicago-area passive home the duo created in River Forest in 2013, the newly constructed Oak Park home on Clinton Avenue is being built to meet the needs of a family seeking to live as efficiently as possible. Passive houses are built to the most stringent building efficiency standards in the world and require a design that allows the home’s envelope to minimize losses and maximize gains, resulting in energy savings and improved indoor air quality.

Design and build

In early December, a crowd gathered inside the shell of the house under construction. With no windows, doors or stair railings, the house tour was not for the faint of heart, but it managed to draw plenty of people interested in green building techniques. The two-story home may have a completely modern feel, but it is designed to fit into a neighborhood of century-old houses. 

Bassett-Dilley noted that his clients wanted something with a craftsman feel and not too big. The roughly 2,000-square-foot house is designed to bring the outdoors in while also meeting some of the strictest measures of energy-efficiency in building.

The owners came to Weiss and Bassett-Dilley seeking an efficient and healthy home and were impressed by the ventilation system and low levels of toxicity in the duo’s existing River Forest project. Bassett-Dilley said they took care to consider not only those factors, but also how the house felt.

“We thought about the functional and aesthetic expressions,” he said. “We want the design to be influenced by performance and for performance to consider design.”

To that end, tall windows are strategically placed for solar gain and good views of the yard. A screened-in porch provides a connection to the outdoors while allowing the home to integrate into the social fabric of the neighborhood.

 Densely-blown fiberglass insulation within a “jacket” provides warmth. Weiss pointed out that once the windows and doors are in place, the heat from the light bulbs alone will warm the strongly insulated, air-tight home

Bassett-Dilley and Weiss stress that the technology used to make a home passive can be utilized in any new-construction home and produces a structure that will stand the test of time. When Frank Lloyd Wright based his Home & Studio in Oak Park and changed the world with his Prairie Style, he put the village on the architectural map for cutting-edge design. 

Bassett-Dilley thinks the interest is there for the kind of homes that will make just as big an impact, if not bigger, given the environmental benefits of passive-house construction.

Weiss believes they are creating a new generation of homes that will be held up as examples. 

“We’re making sure that we’re building buildings that will last for centuries rather than decades,” he said.

While it’s important to think about the environmental impact of building with passive standards, Bassett-Dilley said, in the real world, price is always part of the process. 

“The mindset of these really efficient houses is to optimize the expenditure. We know we can spend a ton of money to get more efficient, but the question is, what is just the right amount in terms of operating costs and mortgages?” 

Passive technology 

Bassett-Dilley, an early proponent of passive house design in Illinois, said standards for passive houses have altered just in the time since he and Weiss worked on the River Forest house. 

“There’s definitely been a big shift in what’s happening with passive houses,” he noted. “When passive house standards were first formulated in Germany, they had basically three criteria they considered to determine whether a house met the passive standard: Was it airtight, how much energy does the building consume, and what is the annual heating demand?”

But the German standards are not completely applicable to the United States, given our varied climate. 

“Germans don’t typically need artificial cooling,” he said, “and the U.S. does. One-size-fits-all standards don’t work when you consider the heat in the South or California or the really cold northern climates like Minnesota.”

Passive House Institute U.S. wanted to adapt German standards to take into consideration the climate in the U.S. while making economic sense. Bassett-Dilley noted that prior to the changes, “you could put in crazy amounts of insulation in really northern climates, chasing a magic number and still not get a payback. The new standards really want to be able to consider heat and humidity and weighing cost-effectiveness versus the heating demand standard.”

Passive House Institute U.S. created a sample building and modeled different climate effects to come up with cost-effective solutions to the climate variances in the United States. They adapted the German standards, and according to Bassett-Dilley, these standards will be up for comment soon before they are accepted.

The Clinton Avenue house benefitted from these expected changes, and Bassett-Dilley expects that the team will be looking at passive house certification as soon as the new standard is adopted. The home is also expected to meet the LEED Platinum standards, a green building certification program that recognizes green building strategies and practices.

The future of passive

While certification is a nice affirmation, Bassett-Dilley believes the techniques he and Weiss espouse are the wave of the future. 

“Whether or not you go for certification, it’s a better way to build than how we’ve been building forever. As energy codes change, this is the future. You will pay a little more for your building, but you’ll save so much on energy costs that you’ll come out ahead. Would you rather spend your money on your property or send it to the big coal company?”

The Clinton house is schedule for completion during the spring, and Weiss and Bassett-Dilley are currently working on four passive houses, with more in the works for next year. 

Next fall, the North American Passive House Conference will be held in Chicago, and Bassett-Dilley said he’s proud of the fact that leadership in the Midwest is coming out of Oak Park.

Passive assertive

“Passive house” is a term referring to energy efficiency in building construction. Passive house construction results in ultra-low energy buildings that require little energy for heating or cooling. The techniques produce an almost airtight envelope in which thermal performance and ventilation are maximized and energy demands are minimized. 

The Passivhaus standard was developed in Germany and in the U.S. is now administered by the Passive House Institute U.S.

Here is the official definition:

“A Passivhaus is a building for which thermal comfort can be achieved solely by post-heating or post-cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions — without the need for additional recirculation of air.”

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