SHOREWOOD - This single family Shorewood home doesn't look much different from any other house on Morris Boulevard.

It sits at about 2,000 square feet with two standard bedrooms and two bathrooms. Upon entering, visitors immediately notice the coolness of the concrete floors and the natural light coming from large windows facing an open kitchen and family room.

The framework of the doorway is unusually thick, which helps the house remain insulated from its outside environment. The walls are also 26 inches thick, the windows are triple-paned and the house's airtightness eliminates the need for a furnace, even during Wisconsin winters.

As a result, this house uses about 90% less energy than other homes. In 2017, it became one of the first certified passive houses in the state — an ultra-energy efficient construction standard that's slowly rising as an alternative building method across the country.

The passive house concept is built on a set of design principles: minimal heating and cooling, thick insulation, energy-recovery ventilation and high-performance windows.

The Shorewood home, named "Domus Matris," began as a team of Jean Linn, her son Tim Linn and architect Bruce Zahn.Juanita Ellis later joined as the team's energy rater making sure the home met the performance standards for its Passive House certification.

Jean Linn said her vision for a green dream home stems from her faith, which she celebrates with religious decor throughout the house.

"(When) God created the earth, he made us stewards of this and we should try to live intentionally, live cleanly, don't waste things," said Linn, who has lived in the house for about five years. "It was trying to keep it as simple as possible and less wasteful as possible."

Jean Linn compares living in Domus Matris to being inside a thermos bottle. It's warmer in winters, cooler in summers, quieter and less susceptible to mold or decay. Less energy reliance means utility bills are lower too.

"This house was very custom built for me," Jean Linn said. "It's very green. It's energy efficient. It's sustainable. It's got woodworking that will last forever."

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The roots of passive building

The idea for energy efficient homes took root in the United States and Canada in the wake of the national energy crisis caused by the 1973 oil embargo.

In the 1980s, as the U.S. shifted away from focusing on energy conservation, Europe took over the momentum of the passive house movement and the world's first passive house was built in Kranichstein, Germany, a little over 25 years ago.

It wasn't until 2003 that Katrin Klingenberg completed a passive-house prototype, dubbed the Smith House, in Urbana, Illinois, that passive houses officially hit the U.S. landscape.

But even today, the U.S. remains home to only about 350 passive homes while about 50,000 have been built worldwide.

To be certified as a passive house in the U.S., site and building components of the proposed home have to be evaluated to make sure the design would meet Passive Building standards set by the Passive House Institute U.S., or PHIUS.

Blower door tests have to be done to measure how air is flowing in the building and materials have to be vetted to make sure they can properly insulate the home.

Michael Knezovich, the communications director of PHIUS, said that while the passive house movement has thrived on the coastal regions of the U.S., it hasn't picked up similar speed in the Midwest.

"I think the Northeast and Northwest have been kind of the hotbeds," Knezovich said. "Even though the first one was built by our founder in Urbana, Illinois, it's taken longer in our own backyard."

Including Domus Matris, only three certified passive buildings exist in Wisconsin — one is a single-family home in Hudson and the other an affordable housing project in the Madison area. Another single-family passive home is under construction in Wheatland.

Knezovich said building costs for passive houses are steadily becoming cheaper as more materials become readily available for builders. The cost of building a passive home varies, but typically the cost is about 5% more than a comparably-sized house using traditional construction methods.

Linn didn't want to talk about how much it cost to build her house, but it is assessed for tax purposes by the village at $212,300 — not that different from comparably-sized homes in her neighborhood.

When early adopters began building passive houses, they could be 15% to 20% higher in cost because materials had to be imported from Europe.

Knezovich said he believes the passive house movement will grow in the Midwest with time, and the biggest barrier remains in spreading awareness of what they are.

"As people realize that not only is it good for the environment and the climate, the indoor comfort level is (also) really high," Knezovich said. "That's going to speed things up too."

Benefits of passive homes

Sean Meyers, a project architect for CR-Building Performance Specialists, Inc. and a certified passive house consultant, said passive homes have are more benefits than reduced energy consumption. Meyers has worked on passive homes in Minnesota and is pursuing one in Mercer.

"A lot of times the focus is just energy saving but in reality there's much more to it than that," Meyers said. "There's increased comfort, durability, lower maintenance, better health with indoor air quality, allergen-free air."

Jean Linn said her experience living in a passive home is noticeably different from when she lived in regular houses.

"It's not loud like when I lived in other houses," Jean Linn said. "The temperature of your house is a little more consistent."

Tim Linn, who built Domus Matris, said when building a passive house, you also have to take into consideration what kind of climate the house is going to sit in.

"If I was building you a house in Missouri, I would build it completely differently," he said during a tour of the home for Historic Milwaukee's annual Doors Open Milwaukee event last month. "The level of insulation in the walls would be different, material choices would be different, type of ventilation system would be different. We built this one (specifically) for here in Milwaukee, Wisconsin."

Windows in the house are carefully located to most efficiently absorb heat and light coming from the sun.

"You try and exploit the sun's energy and in our climate, we're trying to exploit it for heating purposes," Jean Linn said. "The windows in my house are all on the south side of the house, most of them make the best use of the sun."

Bruce Zahn, architect of Domus Matris, went through a rigorous certification process to become a passive house consultant. He said he hopes the trend will pick up across Wisconsin and beyond.

"The Germans were like 10 or 12 years ahead of us so they have 50,000 houses like this built in Germany and Austria at this point," Zahn said. "Our country, because we're behind, we're only a little over (300). This one is the second one that's certified in Wisconsin. Hopefully, there will be more."

How climate change concerns are changing real estate

Knezovich said architectural interest in passive building combines a creative fascination with the structures and an environmental motivation to combat the growing problems of climate change.

He said U.S. interest in these homes can stem back to the Kyoto Protocol of the 1990s, an international agreement linked to the United Nations Framework Convention on Climate Change that set goals for industrialized nations to reduce their greenhouse gas emissions.

"A lot of people who are involved with passive houses are also people who care a lot about carbon emissions and climate change," Knezovich said. "Because (passive building) uses less energy and you can get it to zero, it's going to mitigate climate change by reducing the carbon footprint."

A report released last year by the Intergovernmental Panel on Climate Change, a group of scientists convened by the United Nations, warned last year that continued global warming could cause an environmental crisis as early as 2040.

But scientists say there is already evidence of climate change's impact in the form or more frequent and more severe storms, fires and other natural disasters.

The National Oceanic and Atmospheric Administration reported record levels of extreme storms and natural disasters such as floods, mudslides and wildfires caused $300 billion in damage across the country in 2017.

Susan Campbell, a Milwaukee-based real estate agent, said even though passive houses are still fairly scarce, house hunters have an appetite for greener homes and energy efficient amenities when property shopping.

"Homebuyers and sellers are experiencing the effects of climate change in greater and greater numbers," Campbell said. "Homes that have green or sustainable features sell faster and they sell for more."

Campbell said it's a start for the real estate industry to start openly talking about climate change as a concern. She feels it's a responsibility for real estate professionals to talk to homeowners about cost-efficient sustainable upgrades when it comes to adding energy efficient features to homes.

"When somebody updates their home or puts money into energy efficiency upgrades such as solar panels — you can do much less expensive things, too — that value is then communicated when that buyer puts their home on the market ... it'll save the buyer money for years down the road."

Including climate change in the conversation about real estate is just starting out in Wisconsin, but Campbell believes with more awareness of options for sustainable and green living, the more the industry will shift to answer growing demand for those types of homes.

"You're seeing buyers who may be more aware about this and seeking these homes to pay for them," Campbell said. "It's starting but definitely, we'd like to see more."

Cost-friendly ways to make your home more energy efficient

Switch out your lightbulbs to LED energy efficient bulbs. They'll last longer and you can save some money on replacements.

Have an energy assessment done on your home. A home energy assessment, or energy audit, can tell you how much gas and electricity your house uses and finds ways to help make it more efficient. HomeAdvisor estimates an energy assessment to cost anywhere between $100 to $1,650 depending on the square footage of your home.

Insulate your home better with weatherproofing strips to seal any leaks in your doors and windows.

Contact Mica Soellner at 920-996-7226 or msoellner@gannett.com. Follow her on Twitter at @micasoellner.

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