Builders make headway on energy-efficient homes

LONGMONT — New ideas and technology make creating a net-zero home or building — one that uses no more energy than it produces — increasingly possible.

The key to success is rooted in assembling the right team from design through construction, using up-to-date information and aiming toward the highest standard possible.

“We believe Boulder County is on the cutting edge of building,” said Rich Filipek, principal at Longmont-based general contractor Concept30 LLC. “But the energy codes and the building science is changing so quickly that homes built eight years ago are much less energy-efficient than homes currently being built.”

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With Boulder County’s reputation as a haven for the environmentally friendly, Filipek sees clients interested in net-zero homes but without a plan to get there.

“It amazes me when we get clients who have an awareness about green building … but their homes are being designed to the minimal standard,” Filipek said. “We have a passion for building homes for our clients that aren’t going to be outdated in the near future,” he said.

Finding a designer familiar with net-zero homes and up-to-date on emerging energy efficiency trends is an important part of reaching the end goal of a net-zero home, Filipek said, but the process doesn’t end there. Design, materials, lot choice and builder know-how all factor in to success. One growing movement in the net-zero building community is the Passive House concept, Filipek said.

Mike Knezovich, communications director for the Passive House Institute US in Urbana, Illinois, said passive building is all about how little energy it takes to heat a building. The institute trains designers and builders in a set of concepts, standards and practices shown to improve energy efficiency in a building when properly applied.

“Passive House is maybe the shortest path to net-zero because it minimizes the amount of energy you have to buy,” Knezovich said. The idea originated decades ago in the United States, was implemented and refined extensively in Europe, and is now returning to the United States. A Passive House requires 60 percent to 80 percent less energy than a conventional home, making it easier to hit net-zero. When building to Passive House standards, dozens of elements are considered from beginning to end, such as home orientation, window placement, the local climate, vegetation and shading, materials, lighting, wind impact, and even neighbors’ position. Perhaps most important is creating an air-tight building.

“You accomplish this through minimal gaps in the air envelope and a higher level of insulation,” Filipek said. High-quality windows are essential. Triple-pane windows with high R-values and a customized approach that fine tunes the heat gain or loss of a window relative to its position in the house are all part of it, he said. Proper framing of the windows reduces heat loss or gain from around the window, too.

“If you hit the Holy Grail, you can design a house that doesn’t need heating or air conditioning,” Knezovich said. “The inhabitants and appliances generate enough heat to stay warm.” It’s something he’s seen work in climates like the Pacific Northwest’s. Many areas still need additional energy through on-property produced sources such as solar or through the grid, and all tightly sealed homes need an air exchange system to circulate fresh air.

“It creates a superb indoor air quality,” Knezovich said.

Building a net-zero home costs a bit more, Filipek and Knezovich agree, somewhere between 3 percent and 10 percent more, Knezovich said. Location, cost and availability of materials, and builder expertise drive a lot of that cost difference, but the resulting home cuts energy bills by 50 percent to 80 percent, though, that cost can be recouped.

It’s not just custom homebuilders looking toward net-zero anymore, either. Builders of commercial and multifamily buildings aim for better energy efficiency with a raft of federal and local government incentives, such as tax credits, to help get there.

The Department of Energy’s Challenge Home program pushes energy-efficient building to levels above the traditional Energy Star rating, with tens of thousands of these being built since 2008 and more than 25 percent of new homes built in Colorado now meet the lower energy rating, according to the DOE. A certified Passive House can earn that Challenge Home status, Knezovich said.

Boulder-based architect David Beal recently took a Passive House Institute US certification class. There are lots of ways to get to a net-zero home, he said, but Passive House design is simple and makes sense.

“I think it will become the standard because it’s the right way to do it … and you don’t have to do anything else. The house just performs because it’s built so well,” he said. He’s designed several net-zero homes over the years and expects to do more.

“I don’t think it’s going away in Colorado,” Beal said.” And especially in Boulder County, I think it will become a kind of competition.”