Olive Passive House project.
Courtesy of Phius Olive Passive House project.

With a heightened focus on climate change and decarbonization of the built environment, a search for cutting-edge climate resilient building standards is on the rise—especially with possible federal tax credits from the Inflation Reduction Act. Phius has developed a framework for globally applicable passive house building standards that can serve as a model for the ever-evolving needs of climate-friendly building.

Katrin Klingenberg
Phius Katrin Klingenberg

In Houston, Fly Flat, an infill pocket neighborhood, has integrated Phius passive house standards to address extreme weather concerns and energy-outage prevention. “These homes all share mitigation of climate change and adaptability as a result of climate change designing and building for resilience, habitability and passive survivability during power outages, extreme storms, fires, and other climate-driven events,” says Katrin Klingenberg, Phius co-founder and executive director.

Now with more than 7.4 million square feet of passive building projects certified by Phius, the nonprofit can serve as a model for widespread adoption as the need for climate resiliency increases. To find out more about passive home standards, BUILDER recently caught up with Klingenberg.

BUILDER: How are Phius-certified passive homes serving as a model for environmentally friendly adaption?

Klingenberg: Phius buildings have emerged as a model for environmentally friendly construction simply because they represent the most efficient and affordable path to a net-zero built environment. The comfort, resilience, and energy savings afforded by Phius homes make them ideal places to live in an environment where the climate is changing unpredictably, and replicable models for all shapes and sizes of Phius buildings already exist—from skyscrapers to animal hospitals to ranch homes.

BUILDER: In your opinion, what are some of the benefits of building a passive home?

Klingenberg: Building a Phius home provides a fresh experience for builders and an opportunity to make a difference. Learning the ins and outs of passive building design not only helps builders on Phius projects, but many of those strategies can be used to maximize efficiency on other projects as well. It adds a whole bunch of tools to your toolbox while creating a healthy, resilient building—it’s a win-win.

BUILDER: What are some of the most important Phius standards?

Klingenberg: What sets all Phius standards apart from other passive house certifications is they are cost-optimized and climate-specific. The requirements for Phius CORE certifications align with the climate in which the project is built, and energy-saving measures are weighed with the cost of implementation to find the perfect equilibrium for each project to be zero-energy ready. After such optimization, the Phius ZERO standard prescribes a now very small renewable energy solution taking the project to zero and positive energy performance. Thus, Phius standards go beyond passive and pave the path to a zero-carbon future.

BUILDER: What is one of your favorite passive home projects?

Klingenberg: It is almost impossible to choose just one, but the recently certified 425 Grand Concourse project in the Bronx, New York, is truly one-of-a-kind. Aside from being the largest Phius-certified project to date, it is a multiuse building that serves as an anchor in its community. In addition to its housing units, the 26-story building contains a health clinic, educational facility, supermarket, and community support space. It is the perfect model for the future of high-performance urban construction. On the other end of the spectrum, there are so many beautiful, right-sized single-family homes now everywhere in the country. My own house, the first passive house built in the U.S. in 2002 in Urbana, Illinois, stuns me still in how comfortable and quiet it is and how much it feels like living in harmony with one’s environment by “touching the earth lightly” in terms of carbon footprint.

Fly Flat rendering for Houston infill pocket neighborhood.
Courtesy of Phius Fly Flat rendering for Houston infill pocket neighborhood.

BUILDER: What is commonly misunderstood about passive building and passive homes?

Klingenberg: The most misunderstood aspect is the idea that “passive house'' is just for houses, and in all fairness, this is where it first started many decades ago. But technology has evolved. We now have large multifamily buildings, commercial, and even industrial buildings that have been built to the standard. That is why we prefer to talk about passive building as it is applicable to all building typologies. Another misconception is that passive house itself is a brand and official certification organization or entity. Passive house is a set of principles that can be used and applied in various ways. There are multiple organizations that certify projects utilizing passive house principles, but differences in the standards (climate-specificity and cost-optimization are unique to Phius) often result in vastly different qualities of buildings.

BUILDER: Is there a new project—residential or not—on the horizon you’re excited about? Tell us more.

Klingenberg: Yes. There is the Academy for Global Citizenship (AGC), a public charter school in an underserved community in Chicago, currently under construction. Students at the AGC become environmentally and internationally minded by learning how their choices impact their community and ultimately the world. Once completed, the school building will be a Phius ZERO certified building and thus serve as an example for future global generations to design environments in balance with the planet.

BUILDER: What are some ways builders can lean into passive building?

Klingenberg: I would encourage them to take our Phius Certified Builder (CPHB) training course. It offers real-world insights into on-site implementation as well as advice on both the practical and business concerns specific to passive building. Registration for upcoming courses can be found on the Phius website.

BUILDER: Do you think Phius standards will continue to catch on as there’s an increased focus on climate change?

Klingenberg: Our goal at Phius is to foster a built environment that supports the health of people and planet. To do that, we know zero must be the goal in the built environment, and Phius is the means. We have dedicated our work to helping others to achieve that goal in the best possible way. We recognize there is much work to do to mainstream our solution, but we have a framework that has proved effective and a passionate community of professionals churning out Phius projects, the last few years at an exponentially growing rate. Phius is the perfect fit for builders who want to work on the most cutting-edge, high-performing projects in the world and to make a decisive difference.