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Building for the Future


Colorado could be the next big place for sustainable housing

When Norbert Klebl moved to Colorado from Austria, he didn’t like what he saw. It wasn’t the state’s wildlife or scenery, though; it was the energy inefficient homes. “An Austrian would never want to live in one,” he says.

The Geos Neighborhood

An engineer, Klebl set out to build a community of hyper-efficient passive homes in Arvada. The Geos Neighborhood features 28 net-zero-energy homes with all the standard features of a modern house, except there are no gas lines or even furnaces. The homes are designed to make the most of the state’s sunshine, with solar panels, large south-facing windows and a checkerboard community layout to prevent neighbors from shading each other.

High-performance building envelopes dramatically reduce energy leakage, and sophisticated energy recovery ventilation (ERV) systems are used in place of traditional HVAC. The ERV systems pull in fresh outside air and push stale indoor air out, and an exchanger warms or cools the incoming air as needed. The system allows homeowners to monitor and control carbon dioxide and volatile organic compound levels in the air. If levels exceed the desired limit, the system kicks on to vent the excess particles out of the house. Larger homes in the development also use geothermal heat pumps, drawing additional warmth from the earth below.

RELATED: Retrofitting a Passive Home

The result? Geos homes are 75 percent more efficient than even an Energy Star-certified home, according to Klebl. Additionally, the homes have low to no energy bills. The tight envelope and ventilation system reduce outside noise intrusion. And the ERV system is able to control humidity levels and improve indoor air quality, a major bonus during Colorado’s wildfire season.

So why aren’t there more neighborhoods like Geos in the state? Buildings are the fourth largest source of emissions in Colorado, according to the Colorado Energy Office, and they account for about 40 percent of the energy used in the United States.

Sustainability experts say cost, education and building codes have held back energy-efficient development here—but the tide could be turning.

Shape Architecture Studio

Steve Scribner, a partner at Shape Architecture Studio, says he’s seen a spike in interest in energy-efficient and passive homes since the pandemic. Shape recently designed a duplex in Englewood that’s the first Passivhaus International-certified multi-family home in Colorado, and Scribner says there are several similar projects in the works.

Scribner has worked in New York and Boston, where passive building is more popular, and sees Colorado headed in the same direction. People often associate passive homes with the earth ships of the 1970s, he says, but modern passive construction is much more accessible—and aligned with Colorado’s environmentally conscious population. “I think Colorado is the next little nexus of passive building adoption,” he says. “I think people are starting to see it as normal and not this other, hippy thing.”

Shape Architecture
© Shape Architecture

Additionally, rising building costs have helped narrow the price gap between traditional homes and efficient ones in recent years. For example, triple-pane windows used to be twice the cost of normal windows, Scribner says, but now they’re sometimes cheaper. “It’s become that much easier to make the energy-efficient decision,” he says.

Geos’ Klebl says energy-efficient homes don’t have to be extraordinarily costly anyway. In the Geos neighborhood, excluding the cost of the solar panels, building green increased costs by just 2% to 3%, or about $20,000 to $35,000, depending on the size of the home. Klebl says that extra cost can be quickly offset by a dramatic reduction in energy costs. Rebates and incentives through government programs and utilities can help with affordability too.

Sustainable building also often comes with a higher time cost for builders. Sequencing has to be done just right, and there’s more taping than with a standard home. “It requires a slower, more deliberate approach, and on a mass construction scale, that’s a challenge,” Scribner says.

Emu Passive

Education can help builders learn more about the process and increase efficiencies—saving both time and money. Colorado-based Emu Passive offers nationwide in-person and virtual training courses and consulting on sustainable building techniques. They’ve served about 700 builders, architects and interested homeowners so far and are the main independent trainer for passive house techniques in the country.

Enrico Bonilauri, Emu Passive’s co-founder, says training is helpful even for builders who don’t plan to build strictly certified passive homes. Courses can simply introduce practices builders can integrate into their processes to make homes more efficient. Bonilauri says interest in sustainable building seems to be growing. “From my perspective, I think passive homes are booming across the county,” he says. “There’s a lot of stuff bubbling in local areas. I see a lot of builders drawing a line in the sand and saying, ‘Okay, this is the quality we build to.’”

At least part of the growing interest could be driven by changes in building codes and requirements. In Louisville, Colorado, for example, the city has adopted the 2021 International Energy Conservation Code (IECC) and mandated that all new residential construction must meet a net zero carbon emission standard. All new residential and commercial buildings must also meet other sustainability related requirements, such as having electric vehicle charging infrastructure. Similar mandates are in place in states where passive homes have already taken off. In Pennsylvania, public housing is being built to passive standards thanks to incentives from the state housing agency.

Yet, to many sustainability advocates, the current IECC doesn’t go far enough in its efficiency requirements. The 2021 requirements improve efficiency by just 9% compared to the 2018 code. International passive house standards can reduce heating and cooling needs by 80%, Bonilauri says. The code also doesn’t take local climates into account. “The latest building code allows you to use the same exact windows in Dallas, Texas, or Fairbanks, Alaska,” he says.

In order to make a real dent in energy usage, there’s also a big need to retrofit existing homes and commercial buildings to improve efficiency.

Challenges aside, many are hopeful that Colorado is headed in a positive direction. Shape’s Scribner says building more efficiently is just the right thing to do. “We know we really have to lower our energy use in a much more substantial way,” he says. “It just doesn’t make sense not to.”



  • Corey Dahl

    Corey Dahl is managing editor for Colorado Builder magazine. She has written for a wide variety of news and trade publications, in print and online. Corey has a bachelor's degree in journalism from the University of Colorado and a master's in communications management from Webster University. She lives in Denver with her dog Rosie.

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