WHEN THE ANTONINI FAMILY FIRST MOVED IN TO THEIR ZERO-ENERGY HOME IN LAKE OSWEGO, THE CHILDREN FEARED THE OPEN STAIRCASE. IT’S NO LONGER A SCARY FEAT TO CLIMB THE STARIS THAT CONNECT THE CHILDREN’S BEDROOMS TO THE MAIN FLOOR.

For 100 years, the same house stood on this property, tucked away among the Douglas fir trees in Lake Oswego's Bryant neighborhood. But today, that home has been replaced by something that would have been dismissed as impossible by the original builders.

Here stands the first zero-energy home in Lake Oswego — the result of an 8-year-old who loves HGTV, a mother who built a lifestyle around health and a father who wasn't afraid to get his hands dirty as he laid the foundation for a completely different way of living.

"I feel really good about coming home every night," Eric Antonini says, "knowing that my house, and my car, are powered by the sun."

Ciel Antonini and her zebra socks take a quick break from dancing around the house next to her dad Eric and older brother Baz. Instead of carpets, their house has all hardwood floors, which minimize dust collection and help maintain clean air inside its walls.

To make that happen, the Antoninis — Eric, Denise and their three children — used a combination of solar panels, high-efficiency appliances, an air-tight design and other energy-efficient systems to design and build their home. The zero-energy process can be complex, but the idea behind the resulting structures is simple: These homes have a net energy bill of zero, which means they consume as much — or less — energy than they produce.

Eric and Denise designed their five-bedroom, three-and-a-half bath, 3,300-square-foot home with the help of a local contractor. Eric wore numerous hats throughout the construction process, from project manager to general contractor to laborer, all while coaching the boys golf team at Lakeridge High School and parenting his children, ages 8, 7 and 4.

"I built this house with my hands," he says.

After two years of dreaming, designing and building, the Antonini family now lives in the first zero-energy home in Lake Oswego.

But while a minimalist theme echoes throughout the dwelling — from a kitchen with no cabinet handles to a yoga studio that contains just one basket — it is far from the bare-bones structure one might imagine when picturing life inside a zero-energy building.The Antonini home has all the basics you would find in any typical home: flushing toilets, a refrigerator, a laundry room (though the toilets hang on the walls to minimize space usage, and the laundry room houses just one machine, a dual washer-and-dryer). The hum of the dishwasher can be heard across the kitchen, and a small speaker sits plugged into an outlet to charge. The home features two rock bathtubs and a polished grand piano.

The exterior of the Antoninis house is coated with a liquid-applied waterproof barrier that helps create an airtight seal, the most crucial aspect when building for net-zero energy use.

"The key element is that the buildings are just fundamentally more comfortable," says Stephen Aiguier, the president and founder of Green Hammer. The Portland design-build company, which focuses on zero-energy buildings, worked with the Antoninis throughout the process.

"Once you live in one," Aiguier says, "you're forever changed."

Eric now works for Green Hammer as a business development manager. The company estimates that a fully loaded budget for a typical zero-energy certified home is between $300 and $500 per square foot.

"The components that lead to zero-energy certification add only about 10-15 percent to the overall cost," Eric says. It's the custom architecture and durable materials that can add up.

The Antoninis, for example, decided to only use plywood for the sub-flooring and exterior wall sheathing. That "significantly increases the cost," Eric says, because it's more expensive than its competitor, Oriented Strand Board.

He didn't reveal the home's final cost, but Eric says it was "significantly less" than the estimated $300-$500 per square foot, thanks in large part to his hyper-involvement in the process.

Airtight design

While designing and living in a zero-energy home requires a lot of planning up front, there is a misconception that the occupants have to make sacrifices to reduce their energy consumption. In reality, Eric says, it's more about making choices.

The kitchen features a steam oven, a drawer-style dishwasher and a table where the Antoninis gather for family meals.

Instead of carpets, the house has all hardwood floors, which minimize dust collection and help maintain clean air inside its walls. In place of a large refrigerator and freezer, the family downsized and chooses to eat fresher meals instead of freezing their food for long periods of time. And the most important difference?

That would be the membrane that surrounds the house.

Healthy living goes beyond a healthy building. The Antoninis purchased a small refrigerator to encourage them to eat fresh foods and keep them from freezing their meals

Net-zero homes are built to be airtight, and there are multiple methods for creating that seal. The Antoninis achieved it through a combination of triple-pane windows and sliding doors, 5.5 inches of blown cellulose and 3 inches of foam insulation, and a liquid-applied waterproof barrier that coats the outside of their home. Each feature helps control airflow and reduces the amount of energy lost through the structure's shell.

The home also includes a high-efficiency heat pump for heating and cooling and a dedicated heat-recovery ventilation system. All of the Energy Star appliances are electric, including an induction cooktop, and all of the lighting is LED. The resulting heat load in the home is now only 10 percent of what a code-built home would be, Eric says.

"Most homes have on a shaggy sweater with a bunch of holes in it," Aiguier explains, referring to standard insulation. "This building is like a down jacket with a Gore-Tex parka."

Heating and cooling are typically the biggest energy loads in a building, Aiguier says, making up between two-thirds and three-quarters of the average home's energy use.

"By putting the parka and the down jacket on the building," he says, "you just reduced that 90 percent" and zero-energy use becomes attainable.

Powered by the sun

One of the goals for Denise and Eric Antonini was to design a bedroom that doubled as a sanctuary. The solid rock bathtub to Eric's right accents the bathroom that opens to the master bedroom.

In Oregon, where it feels as if it rains for 10 months every year, the idea of building a home that depends on the sun for energy may seem daunting. To completely power a typical house in Lake Oswego, for example, you'd have to fill an entire roof and lawn with solar panels.

"But as we shrunk that energy load down," Eric says, "it became feasible to actually get enough solar on the roof to offset all the energy that we would consume."

Seven-year-old Baz dives into the second rock tub in his home to fish out a toy shark, his favorite animal. Not Pictured: a shark t-shirt to match the socks.

The family worked with Earth Advantage, a nonprofit that calculated the amount of solar energy the Antoninis would need to collect every year to offset their power use. They based their calculations on living conditions for six people, although there are only five family members — and a large dog — living in the house.

They purchased their 11.3-Kw solar array based on those numbers and, since late March when they moved in, the Antoninis have produced more energy than they have consumed.

Of course, summer months are the sunniest in Oregon. So the excess energy the home produces has gone back to the power grid, and the Antoninis will pull from that source when sunshine is scarce and they are not able to produce as much solar power.

A healthy change

While an entire home powered by sunlight is a fantastic thing for the environment, zero-energy use wasn't the only factor the Antonini family considered. "It was one of our loftier goals, but it wasn't our No. 1 goal," Eric says. "Our No. 1 goal was a healthier house."

When they first bought the property, Eric and Denise actually planned to restore the house that had stood in the same spot for 100 years. However, during the first phase of their restoration process, their 8-year-old son Lorenzo got sick. He had been helping his dad with the project when he started coughing frequently; his parents were worried that they might be heading down a path toward asthma, so they asked themselves, 'What can we do to avoid this?'

“If you want to see what our life normally looks like,' Denise Antonini says, 'this is it!'

From the mold that a lack of ventilation could cause to the chemicals that are released as materials deteriorate, Eric says, "we're living and working in sick buildings." But as it turns out, zero-energy homes are among the healthiest places to live.

Denise, the CEO of a company called You and the Mat, has always prioritized healthy living. She has a background in health psychology and had a private practice in Washington, D.C., that specialized in wellness and prevention. She moved to California and opened You and the Mat with Eric, and continues to oversee the yoga studios from Oregon.

"The health and wellness piece has been a thread throughout this process," she says.

After deciding to tear down the old structure and start fresh, the couple prioritized healthy decisions, from the bedsheets they purchased to the foundational structure of their home. And Lorenzo helped his parents install a top-tier ventilation system that improves air quality and keeps moisture levels at an even 50 percent within the home, even with its airtight parka.

To Denise, that's one of the most rewarding parts about building the home from the ground up. "I know the air is clean," she says, "and I know exactly what's in the walls. We mapped out something that worked for us."

According to Eric, no one in the family has been to the doctor since they moved in.

Living simply

The family's shared passion for yoga and meditation is reflected in the home's minimalist theme.

"It's all about this idea of waking up for your life and making conscious decisions all the time," Eric says. "In the context of this house, you can be really intentional about everything you that put into it and how you design it."

There remains the chaos of family life, of course — toys scattered across the floor, a 10-foot pirate ship being built in the boy's bedroom, a pair of zebra socks on their 4-year-old daughter as she dances up the staircase. But the Antoninis have eliminated the excess.

River rock lines the Antonini home to collect stormwater runoff.

"The things that we have are things that we love and care about," Denise says. "We don't have the extra."

The house lacks the constant glow of TV screens in every room, for example. In place of a microwave, there is a steam oven. There are no gutters on the roof, but rather river rock on the ground that filters the rain water. (Yes, City code requires every home to have gutters. And yes, river rock meets that code.)

According to Denise, the home is built around the Japanese term "wabi-sabi,"' which refers to finding the perfect in imperfections.

"For us, that means understanding that as we grow in the house, there are going to be things that aren't exactly the same as when we moved in here," she says. "And that's the beauty of it."