Chris and Ann Vonde’s new contemporary home in the Boise Foothills is beautiful inside and out.
But there’s more to this new house than meets the eye. The 3,200-square-foot home near Table Rock will soon be the first officially certified passive home in the area as designated by the Passive House Institute US (PHIUS).
“It seems like the right thing to do,” Ann said. “It’s maybe marginally more expensive, but the product you get is of such high quality that any cost difference is mitigated over time.”
“We were environmentally conscientious and willing to invest in sustainability,” Chris said. “It’s nice to be innovative with something that nobody else has that is the direction of the future in energy efficiency.”
But there is nothing experimental about this home. The Europeans have been on top of this for several years. What this house achieves is the standard for new construction in many modern cities.
This building method was developed in Germany in the early 1990s and has continued to grow in popularity and technique over the years. There are more than 25,000 certified buildings across Europe, including schools, hospitals, factories and supermarkets. Here in the U.S., the numbers are still under 200, but climbing fast.
So where did the Vondes get the inspiration for their home?
It just so happens that Ann’s brother, Scott Yribar, has a master’s degree in architecture and is a PHIUS Certified Passive House Consultant and Builder.
Yribar recently worked at an architectural firm in Switzerland, where he learned more about Europe’s focus on homes and buildings that are designed to these standards on a regular basis.
Yribar and Steve O’Connor, also a PHIUS Certified Builder, co-founded Enerform in Boise in 2013 to focus on highly energy-efficient and sustainable architecture. The Vonde home will be their first PHIUS-certified home in Idaho. (Yribar also worked for an architectural firm in Salt Lake City, where he helped design that state’s second passive house.)
The Vondes had found a lot in the Foothills just uphill from where they were living at the time. They loved the location, and they were ready to build a new house. Ann’s brother, of course, got into the conversation, and it didn’t take much for Ann and Chris to be convinced of the viability of such a design.
“It was an opportunity for us to help him start his business as well as to get a product we were really excited about,” she said. “We have a lot of confidence in Scott, and he has all the modeling software that shows it’ll work.”
Ann, as a deputy attorney general in the Natural Resources Division in the Idaho Attorney General’s Office, was already well versed in the aspects of environmental impact and related issues. She recently attended a presentation where she learned almost half our energy load comes from coal.
“You can make a huge impact with a house like this,” she said. “If you’re an ecologically conservation-minded person and thinking about building a new house, this is a wonderful way to live out that ideology. It’s honestly easy. There was nothing (more) difficult about building this house than it would be for building any house. ... People should consider it. It has probably a bigger impact than buying a hybrid car in terms of carbon footprint.”
Homes built to these standards can boast up to 75 to 80 percent less energy consumption than a home built to current code. One of the reasons this movement exists to such a great extent in Europe is that it also reduces carbon emissions. According to the U.S. Energy Information Administration, our homes and businesses can account for nearly 40 percent of all energy consumption and more than 30 percent of our carbon emissions.
While the original cost of building a passive home might be about 10 percent more than a current-code house, green-certified homes at resale in California are getting a 9 percent premium over market value, O’Connor said.
“They were generally just getting the money back at the time of sale,” he said.
Kris Wilson, a project manager with the U.S. Green Building Council in Idaho, says everyone should consider the long-term costs of this type of construction.
“Don’t just think about the costs of adding insulation; think about your long-term savings over time,” he said.
The next step after a Passive Home is a Net Zero Home. The Vonde home is net-zero ready and will eventually have solar panels installed. Net zero means the total energy used by a home or building annually is roughly equal to the amount of renewable energy created on-site.
“By the year 2035, it’ll be the norm,” Wilson said. “That’s my prediction.”
While getting the home to work as planned may take a healthy knowledge of calculus and a complex spreadsheet program, the design elements are actually pretty easy to understand.
It’s all about the envelope.
You build a super-insulated shell with double- or triple-pane glazed, insulated windows and put in a good heat-recovery ventilation system. Everything else is just a house.
But that also means most of the work is done in the planning stage. Every single element becomes a number. (Retrofitting, while also possible, presents its own unique challenges.)
“You can make it out of whatever materials you want; you just have to make the numbers work,” Yribar said. He uses three basic metrics — the annual heat demand, the overall energy used and the airtightness level — and he plugs those numbers into what he calls the most impressive Excel sheet he’s ever seen. Everything and everyone becomes a number.
“We’re taking a set of components, and you can arrange them however you want so you can hit these energy metrics,” Yribar said. “How much energy can I use for heating, how much can I use for cooling, how much can we use for all of our lights and plug loads? The cool thing about the standard is that it’s performance based. We have this target number we’re trying to hit. We can adjust things. We can adjust our walls at a certain R-value, we can do our roof at a certain R-value, but if for some reason we need to compensate in what we accommodate in one area, we can adjust the form and massing of the house. It’s a combination of all these different components — the windows, the insulation, the way you orient the house, and it’s this software, this modeling program, that allows you to optimize all of these components.”
It starts with the insulation. And that starts with something called EPS Foam (Expanded Polystyrene). It is similar to the stuff Styrofoam cups are made of, only denser.
“Basically what we did was make a big bathtub out of foam and filled it with concrete,” Yribar said. “Everything under the home has two layers of foam, so it’s six inches thick — two layers, three inches thick. I think it’s like R-25 under the house.”
“I thought watching the whole process from start to finish was interesting,” Ann said. “And the quality of the product you get is really astounding.”
“Contrary to any other home in this area, this entire house rests on foam,” Yribar said. “There is no part of this foundation that touches soil. People are concerned it’s going to collapse or disintegrate, but they make highways with this stuff.”
“When Scott was designing the house, he was carefully weighing the pros and cons of every assembly and every inch of insulation. He’s not just using rule of thumb,” said Skylar Swinford of Energy Systems Consultants. Swinford did the third-party verification to ensure that Enerform’s design worked at every stage of planning and construction.
“Scott has built a very specific energy model that balances all the energy into heat gains, heat losses, the cooling loads, the ventilation loads, the occupant gains ... he has a very detailed model of the house, and I’m going out there to verify that what he put in the energy model and drew in his plan is actually being implemented,” Swinford said.
He said Enerform did everything right.
“Scott is a rare case,” he said. “If a typical builder had never done a passive house or an architect had never done a passive house, I would have had my work cut out for me.”
After the insulation, the windows are next. We all know about air leakage around and through our windows. Buying double-pane windows is the easiest thing we can all do in our homes to improve energy consumption and heat loss and gain.
A passive home takes that to another level. The windows are more like see-through walls with external roller shades for those times when you might want to keep the sun from adding extra heat to the home.
“The windows (in the Vonde home) are nice triple-pane casement windows,” O’Connor said. “That’s another component about how you make a passive house. You use high-quality, insulated frame, triple-pane windows.”
“Good windows are key,” Yribar said. “You can’t really make it work without well-insulated windows.”
The Zola Windows used in the house are not made in the United States. These triple-pane windows (with argon gas trapped between them) had to be shipped from Poland.
But the thick windows still open easily — impressively, they can both swing in or tilt in with a simple turn of the handle. (That makes them easy to clean, too.)
Windows like these add to the initial expense of the house, but over time you’ll save in energy costs, and they bring so much light into the home.
“The windows and the view were worth every penny,” Ann said.
“It was pretty cool to integrate not only the exterior but also the interiors as well,” said Chris, a Boise financial consultant. “We’ve got this view we really want to capture… with big windows, and then find some way in winter to preserve some of the energy.”
“It’s the prudent thing to invest in the envelope,” Yribar said. “You have one shot to design the envelope to a good standard. This is the chance to reduce the (energy) load for a long time.”
“The other really nice livability factor is it is super quiet in here. Because there is so much insulation, you can’t hear the dogs barking out in the yard,” Ann said. “That’s been something we didn’t expect, but it’s been a really nice thing to have.”
The ventilation & heating/cooling
Once the windows have completed the super insulation of the home, the other key elements are the ventilation system that brings fresh, filtered air through the house at a slow, steady rate and an efficient heating/cooling system. The airtightness is what makes it all work.
Airtightness is the primary test Swinford performs to verify that all the numbers plugged into the modeling program are matched in reality. He says it is the most stringent airtightness standard in the world: “Point one percent of one percent of all buildings in the world in terms of airtightness.”
The ventilation system is the high-tech part of the house. This is the breakthrough that allows these houses to work. And they are more than 90 percent efficient. There are two types of recovery ventilators to choose from, depending on climate. They clean the air (removing outdoor pollutants and pollens) and recover heat that might otherwise leave the house. Another aspect is the ability to maintain humidity. You are completely controlling the air quality and temperature because there is no leakage in the envelope from random spots like gaps or cracks, dirty crawl spaces or dusty attics. (This house does have a highly efficient, natural gas water heater.)
Normal infiltration, or leakiness, of an average house might see 5 to 7 air changes an hour. Current code is 7 per hour. New homes might be as low as 3 air changes per hour. But in a passive house, that rate is .6 per hour.
For heating, the Vonde house has two little units called mini-splits that are simply ductless air-sourced heat pumps.
“It’s a cool part of the house,” O’Connor said. “You go into the mechanical room, and there’s a big device there that brings in fresh air from the outside and runs it through a filter, and then distributes it throughout the house. There are 10 ports where it pumps fresh air and there are 10 exhausts, like from the bathrooms and kitchen, that pull air out at the same rate. So it’s just cycling fresh, filtered air through the house.
“It’s going to have the best air quality of any home you’ve ever stepped in,” he said. “That runs 24/7. We plug it in, and that thing will go for decades without ever turning off.”
It’s very quiet. There is no furnace kicking on and off, there is no wind blowing through the vents.
“The loudest thing in the house is the refrigerator,” Yribar said.
The temperature is so steady and comfortable that Ann said one of the first things they had to get used to was not turning down the thermostat at night and wrapping themselves up in a warm comforter.
“It’s a different mentality about what you’re trying to do with the heat in the house, which has taken a little getting used to, but once you figure it out, it’s really nice,” she said. “I never feel cold in here.”
Plus, there’s the benefit of fresh and filtered air. “It feels like it’s spring every day, because there is constant, fresh air coming into the house,” Chris said.
The system also eliminates most moisture and mold problems.
“You’d have to put a hose in the wall to really cause a mold problem with this type of wall assembly,” Swinford said. “It’s designed to last the life of the structure without any mold problems or any issues. Americans spend almost 90 percent of their time indoors, and if you can ensure that the place where you sleep and do most of your living is a high-quality indoor environment, it’s going to have some level of impact on your health.”
“An airtight house is just an indication of the high quality of construction,” Swinford said. “A modern home should have ventilation anyway, so you might as well take advantage of making the shell tight.”
“It’s a win-win. You’re reducing your energy demand and increasing your comfort,” Yribar said.
And it looks no different from any other home. “There is no visual cue that the house is much different than anyone else’s,” O’Connor said.
“The experience of it isn’t different than any other lovely house you might want to build,” Ann said. “You can have a little craftsman bungalow down in the North End and have it be a passive house. No problem. The end product is a pretty nice house, but you also get all these added benefits of energy savings and doing all these things of reducing your carbon footprint.”
Enerform at enerform.com: Scott Yribar and Steve O’Connor’s Treasure Valley design-build company creating highly energy-efficient and sustainable architecture.
ESCO (Energy Systems Consultants) at energysys.co: Skylar Swinford is a Certified Pasivhaus Consultant, PHIUS+ Rater and a BPI-certified Building Analyst and Envelope Professional.
PHIUS (Passive House Institute US) at phius.org: Founded in 2003, this organization is working to make high-performance passive building the mainstream standard.
U.S. Green Building Council Idaho (USGBC) at usgbc.org/usgbc-idaho: This organization is helping to transform the way buildings are designed, constructed and operated through LEED certification (third-party verification). The Idaho chapter can help you find local resources and information.
Idaho Conservation League (ICL) at idahoconservation.org: The ICL partners with a variety of groups across the state to preserve water, wilderness and quality of life.
Idaho Power at IdahoPower.com/save: Learn how to make small changes to reduce energy consumption.
The Vonde home team
Civil engineer: RiveRidge Engineering
Structural engineer: Murar Engineering and Design
Mechanical Engineer: Sage Consulting Engineers
PHIUS+ Rater: Energy Systems Consultants
Excavation: Hard Rock Construction
Concrete: Core Design Build
Concrete finishing: The Concrete Cure
Windows: Zola Windows
Insulation: EnergySeal Air Barrier Systems
Exterior carpentry: Enerform
Roof: Scott Myers and Sons Roofing
Plumbing: Rob Goodson Plumbing
Electrical: Burke Electrical Contracting
Heating and cooling: Owyhee Heating & Air Conditioning
Drywall and stucco: Western Wallboard Systems
Finish carpentry: Wasatch Woodworks
Hardwood floors: Clearspan Carpentry
Tile: Rob Harder Construction
Kitchen cabinets: Cameron’s Custom Cabinetry
Countertops: Stone Pro
Landscaping: Madeline George/Think Green
With spring here, it’s prime time to check out new homes or think about that remodel you’ve been putting off. Mark your calendar for these events.
Boise Parade of Homes: April 30-May 15 bcaswi.org
Canyon County Parade of Homes: June 10-26 srvbca.com
11th annual St. Jude Dream Home Giveaway: This year’s 2,400-square-foot, 4-bedroom home with a mother-in-law suite is located in the Reflection Ridge community in South Meridian between Victory and Amity roads just west off South Locust Grove. Tickets are available now for $100. For the fourth year, the home (valued at $375,000) is being built by Berkeley Building Co. The drawing will take place June 12. Home tours begin weekends starting April 30. dreamhome.stjude.org/boise
12th annual NARI Remodeled Home Tour: June 4-5 nariofidaho.org