Women at WIRC: Kat Klingberg on What's Next in Residential Construction

This episode of Women at WIRC features Katrin Klingenberg, Executive Director of PHIUS, The Passive House Institute-US, interviewed by Pauline Hammerbeck of Custom Home and Pro Builder. The topics ranged from the origins of passive building in the U.S. to adapting standards for different climates, misconceptions about airtight construction, costs and payback, resilience during power outages, and the growing market momentum for passive building.

Transcript:

Pauline Hammerbeck (Host): Welcome to Women at Work. I’m Pauline Beck, editor of Custom Builder. In this episode, we’re talking to Kat Klingberg, a woman who built the first certified passive house in the U.S. back in 2003, founded FIAs—the nonprofit Passive House Institute—and has been in the trenches training builders, architects, and all manner of professionals on high-performance homes for more than 20 years. Welcome, Kat.

Kat Klingberg (Guest): Hi, I’m so glad to be here. Thank you for having me.

Is interest in passive building growing?

Pauline: Thank you for being here. With everything we’re seeing—rising energy costs, more destructive weather events, indoor air quality growing in importance, especially post-COVID—and in my conversations with architects, builders, and designers, it feels like there’s a shift. There seems to be more interest lately in the passive approach. Would you agree?

Kat: Absolutely. Interest is skyrocketing. We’re working very hard on hundreds of projects, and we’ll probably cross into the thousands soon.

What drew you to passive house?

Pauline: You were an early adopter—everybody’s kind of joining you now. What drew you to the passive house approach in the first place?

Kat: At the time, I had just finished my master’s in architecture and was working in conventional firms. The climate challenge was front and center in my mind, and I wanted to use my profession to make a difference. That drew me to passive house.

Why build your own home using this approach?

Pauline: What was it specifically about the approach? And tell me how you decided to build your own home using it.

Kat: In the U.S. at that time, there wasn’t much happening in terms of super-insulation or whole-systems thinking. Cutting-edge projects in Chicago were just 2x6 walls with fiberglass insulation.

I had studied in Berlin, where passive house was already being discussed in the early 1990s. I thought, we can do better. I was sure the world was heading toward net zero, so I decided to build a prototype to show how it could be done.

What was the most difficult part of that first project?

Pauline: Since it was early on here in the U.S., compared to Germany, what was the most difficult part?

Kat: There were challenges, but I like experimenting. I translated what they had done in Germany to local materials and conditions. The cool thing was that I built my home in Champaign, Illinois—and I discovered that passive house ideas had actually originated in Champaign-Urbana.

The Germans were inspired by the super-insulation and high-performance building work done here in the 1970s at the Small Homes Council. So, in many ways, I wasn’t alone—the technology and knowledge were already here.

Would you have done anything differently?

Pauline: Looking back, would you have done anything differently with that first project?

Kat: Oh yes, I made plenty of mistakes. I initially copied the German approach one-to-one. But the U.S. climate—hotter summers, colder winters, greater swings—requires different measures.

I over-insulated my house, thinking only of a heating-dominated climate. But in reality, I was in a mixed climate with cooling and dehumidification needs too. At FIAs, we learned from this and adapted the standard to every climate and building type.

Why did you believe this would work in the U.S.?

Pauline: When you were starting out, passive house was still niche. What made you think it would work more broadly in the U.S. market—that FIAs could take hold?

Kat: I believed the U.S. was innovative and could pivot quickly if the idea was good. I also discovered that in the 1980s there had already been a passive house movement here—30,000 units built. Realizing that, I knew we weren’t starting from scratch. It wasn’t a technological problem; it was a market transformation problem.

What are the biggest misconceptions?

Pauline: After decades of work, what misconceptions do you still hear from builders or architects about the approach?

Kat: Two big ones:

1. The name “passive house.” People think it’s only for houses, but we certify high-rises now—32 stories, even a 53-story tower in Brooklyn. That’s why we rebranded as FIAs, focusing on “passive building.”

2. The idea that “buildings need to breathe.” Yes, they do—but not through dirty cracks. We want intentional ventilation and filtration. And yes, you can open the windows in a passive building.

How do you account for regional differences?

Pauline: You mentioned regional differences earlier. How does FIAs account for that—for example, Florida versus Minnesota?

Kat: When I started, there was just one global standard. I was the guinea pig who realized we needed climate-specific standards.

At FIAs, we partnered with Building Science Corporation and the National Renewable Energy Lab to adapt targets for heating, cooling, and loads in different climates and building types. That way, the standard works everywhere.

Is there a project you’re especially excited about?

Pauline: Is there a project currently underway that excites you?

Kat: Yes—one in Milwaukee, Wisconsin. It’s a 32-story CLT tower, market-rate housing with a very striking design. We’ve had great success in affordable housing, but this is a milestone for market-rate development. They’re marketing it as a healthy lifestyle, and I hope it inspires other developers.

What about costs and payback?

Pauline: Let’s talk about costs. Are we talking 10%, 20% upfront? How soon can developers expect to recoup costs?

Kat: For single-family homes, it can be harder. But for multifamily buildings, passive building is cost-effective. In Massachusetts, after a state-sponsored competition, additional costs averaged just 2–3%. Developers said they couldn’t afford not to do it.

In New York, a large project came in at only 1.7% extra cost, with a 12-year payback. After that, it’s all savings.

Beyond energy savings, what about resilience?

Pauline: Passive building started with energy savings. But now we hear more about resilience. Is that a focus?

Kat: Absolutely. Passive buildings stay habitable during outages. In Austin, a certified passive house stayed comfortable during a winter grid failure. In Houston, homes stayed livable during extreme heat and power loss. Studies show passive homes provide many more safe days than code-built homes when the grid fails.

With more electrification, the grid will be strained. Efficiency is key to resilience.

Is the market ready to make passive mainstream?

Pauline: Do you think the market is ready to make passive building the default standard?

Kat: We’re getting there. Massachusetts is leading with code requirements, and other states will follow. There’s momentum, but we need a mindset shift away from “too much upfront cost” thinking.

Does electrification help or hurt?

Pauline: New York just mandated new buildings be all-electric. Does that help or hurt your cause?

Kat: It helps—but only if paired with efficiency. Electrification without efficiency strains the grid. Efficiency plus electrification is the sweet spot.

How can someone get started?

Pauline: For someone interested but without a building science background, what’s the fastest path to get up to speed?

Kat: Start with our Foundations training—online, accessible, and it leads to a FIAs Associate credential. Developers should also hire experienced consultants early. Builders and architects should start gaining building science knowledge now. It’s fun, it makes people healthier and safer, and it’s time to retool.

Where can people learn more?

Pauline: Where should people go to learn more about passive principles and your organization?

Kat: Our website is full of information. We also have the Passive House Alliance with local chapters across the U.S. Our annual conference moves from city to city; this year it’s in Milwaukee. It’s open, collaborative, and a great way to learn whether you’re a beginner or a pro.

—Women at WIRC is a spinoff of the Women in Residential Construction conference hosted by Pro Builder and Pro Remodeler.