Looking back and ahead at passive building

Today PHIUS delivers its CPHC training virtually and and across the country, and in partnership with organizations like Yestermorrow and the U.S. Army Corps of Engineers. It all started with the first class in Urbana, Ill., in 2008, pictured above. Bottom row, from l-r:  John Essig, Dave Brach, Mary Graham, Katrin Klingenberg, Laura Briggs, Jonah Stanford. Second row: Christina Snyder, Luis Martinez, Jim Olson, Lance Wright, Paul Eldrenkamp, Hayden Robinson, Henry Gifford, David White, Graham Irwin. Back row: Katia Sussman, Tim Moran, Ian Schnack, Al Hothan, John Highland, Gino Mazzaferro, Mark Hoberecht, Ed Shank, Bogdan Zagorowski, Jesper Kruse, Steve Robinson, Matt Howard, Tim Eian, Harold Finigan, Vahid Mojarrab, Tad Everhart, Marc Rosenbaum

I wrote in my last post about how my diagnosis with MS motivated me to rebalance my lifestyle and nutrition. One other positive by-product has been an opportunity to reflect. Once again, reflection and mindfulness – like good nutrition – have always been a goal. But the MS forced the issue by slowing me down (at least for awhile).

And I was reminded of what a rich and wonderful journey it’s been, and how far we’ve come together.

When I set out a dozen years ago, it was not simply to advance passive house principles. It was to help shrink our carbon footprint—and the effects of climate change. Passive building seemed then as it does now to be a critical part of the solution.

I started by building my own residence in Urbana, Ill. Then Mike Kernagis joined me as construction manager on two affordable passive houses built in partnership with the City of Urbana. One other affordable home was built in 2011, and we designed three private homes. And, the Solar Decathlon Home 2009 came home from D.C. after placing second, bringing the number of passive homes in the Champaign-Urbana area to eight.

The reaction — from points far and wide across the country was — so strong and positive that we assembled the first English language CPHC (Certified Passive House Consultant) training program in 2008.

It’s been a whirlwind since then. In 2009 we founded the Passive House Alliance US (PHAUS) and communities of our trainees coalesced in their respective regions, forming groups such as PHCA, PHNW, NYPH and PHNE. PHAUS, a PHIUS program, has added more than a dozen chapters under the PHAUS umbrella nationwide.

Most important, we deliver the training nationally and virtually now, and the community of PHIUS-trained CPHCs (now 550+ strong) started building real, successful projects across North America’s climate zones. Some of the bleeding edge heroes of the effort include Dan Whitmore, Jan Fillinger, Win Swafford, Tad Everhart, Blake Bilyeu, Randy Foster and Tessa Smith, Alex Boetzel and Stephan Aiguier, Rob Hawthorne, Margo Rettig, Jesse Thomas, Joe Giampietro, Graham Wright and Sam Hagerman in the Northwest. In the Bay Area, the torch was carried by Allen Gilliland (the first NZE home in Calif.), Graham Irwin, Rick Milburn, Nabih Tahan, Lowell Moulton, Katy Hollbacher and Prudence Ferreira.

The Northeast honor roll: Laura Briggs, Paul Eldrenkamp, Marc Rosenbaum, Peter Schneider and J.B. Clancy, Mike Duclos and Paul Panish, Alan Gibson and Matt O’Malia, Svea Tullberg, Jesper Kruse, Stephanie Bassler, Jesse Thompson, Laura Blau, Tim McDonald, Chris Benedict and Henry Gifford, Dennis Wedlick, David White, Ken Levenson, Jordan Goldman and Stephanie Horowitz, Andreas Benzing, Julie Torres-Moskovitz.

David Peabody, Adam Cohen, John Semmelhack, Michael Hindle, Barbara Gehrung, Alan Abrams and Dan Levy have led the way in the Mid-Atlantic region; Chris Senior, Clarke Snell and Jeff Buscher in the Carolinas; Ed Shank and Mark Hoberecht, Eric Lang, Pat Murphy, Mary Rogero and Faith Morgan in Ohio.

In Kentucky, Ginger Watkins and Michael Hughes have been leaders; way up North Stephan Tanner, Tim Eian, Carly Colson, Rachel Wagner and Mike LeBeau carried the banner. Lance Wright and Brian Fuentes sparked the community in Colorado; Joaquin Karcher and Jonah Stanford in New Mexico; Dave Brach in Salt Lake; Vic Weber in Idaho; Ross Elliott and Natalie Leonard in Canada; Thorsten Chlupp in Alaska: Linda Metropulos, Laura Nettleton and Michael Whartnaby in Pennsylvania; Tom Bassett-Dilley, Mark Miller and Patrick Danaher in Chicago. Finally, Dave Stecher, Dylan Lamar (who also did the first IP version of PHPP while at PHIUS, a critical step), Ian Schnack, Ryan Abendroth and Darcy Bean helped blaze trails back at home in Urbana, and later on their own in Phoenix, St.Louis, Portland Ore. and Pittsburgh. Pa.

There are more—like Corey Saft who had the gumption to build a passive house in Louisiana. We learned so much from that project. Surely I am omitting people – I apologize for any memory lapse. The point is, there’s no substitute for all of your commitment. I feel privileged to be part of your community.

We are headed toward our 9th Annual Conference, and today, in addition to CPHC training, we offer PHIUS Certified Builders Training, and a PHIUS+ Rater training that enables HERS raters to accurately rate passive houses. These programs are relatively new, but the Certified Builder program is always sold out and already the community of PHIUS Certified Builders is approaching 100; and the Rater community is right behind it.

We’ve forged strategic partnerships with the likes of the U.S. DOE, Building Science Corporation, RESNET, Rocky Mountain Institute. We’ve also established  relationships with the prestigious Fraunhofer IBP, Owens Corning and Oak Ridge National Lab—a partnership that produced WUFI Passive. WUFI Passive is a fantastic software modeling tool that is making passive energy modeling easier, more accurate, and integrated with WUFI hygrothermal analysis. It’s a commercial grade software tool with a streamlined GUI and the most powerful passive and hygrothermal modeling capabilities on the market. It is, simply, a leap forward.

Looking back, I see there was another critical group—and I mean critical. Let’s call them the passive house skeptics. They’ve ranged from Marc Rosenbaum to Joe Lstiburek to Martin Holladay.

When I set out to prove passive house principles in the United States, I was energetic, armed with information from the German PHI, and … a little naïve. Passivhaus was new to me and the majority of people I talked to about it. And I thought—like a lot of like-minded people—that I’d discovered something brand new.

After I built my own passive house in 2002, and we started getting some attention in the mainstream and trade press, I began hearing from energy conservation pioneers. On one hand, they were excited to see conservation back on the front burner, after interest in it trailed off back in the 80s.

But some were also a bit miffed. I didn’t understand it at the time – and misunderstood it as resistance to change. It was quite the opposite. It was the notion that this passivhaus or passive house was new that was irksome to them.

Indeed, I learned that the foundation principles that distinguished what I called passive house in English or passivhaus in German were not at all new. Superinsulation, high-performance doors and windows, removing thermal bridges, energy recovery ventilation/minimizing mechanicals, managing solar gain. A group of pioneers — including some in my own backyard in Urbana at the University of Illinois—had formulated these concepts decades earlier.

What we have learned – and I say we because we’ve learned it side-by-side with CPHCs and builders who’ve faced real-world challenges across climates—is that this group of early pioneers had valid misgivings about passive house as formulated in Europe. The concerns included the small-house penalty, North American issues with latent humidity, and the cost-effectiveness of investing in the envelope as opposed to renewables. The biggest concern: deep disagreement that a single numerical standard for all climate zones could make sense.

Reasonable people can and will disagree. But on the single standard, we at PHIUS have come to agree that a one-size-fits-all-climates standard is flawed, and is a major factor holding back adoption. I, like a lot of people, found the notion that a single number could work for all climates magnetically attractive. But in our experience designing, building, certifying and monitoring, we’ve concluded it doesn’t work. That’s an important departure, but not a disagreement about passive house principles being the best place to start for high performance building.

That’s why we’re engaged with Building Science Corporation in testing climate-specific standards that use the peak load calculation (which underlies also the European standard) as a baseline. (BTW, again—climate-specific doesn’t necessarily mean “easier.” In some climate zones, we expect the standard to tighten.)

Now, make no mistake: When interest in conservation waned in the United States and Canada in the 80s, the efforts of Drs. Bo Adamson and Wolfgang Feist to formulate passive principles for Europe were heroic, and Dr. Feist’s continuing efforts with PHI have been invaluable. In particular the PHPP was an important step toward putting modeling within reach of passive house professionals. We owe them gratitude. But the work of our entire community, the advancement of building science and innovation must quite naturally go on. There is no holy grail here.

Some lament the differences that exist within the passive building community. To be sure, some of the harsh rhetoric and hurt feelings have been regrettable (and, I think, entirely avoidable moving forward). But we see different and competing ideas as healthy and necessary. It’s only natural that as a community grows, it grows more vital and diverse, and that competing views—and to be sure, competing interests—arise.

The entire passive house community, regardless of scientific position or organizational loyalties, is pulling toward conserving energy and reducing carbon emissions, while constructing extremely comfortable, healthy and resilient buildings. And we agree that passive is a great way to do that. But honest competition has always driven growth and innovation. Trying to put a lid on ideas suppresses growth, and leaves us fighting over a very small pie.

Here’s to a vibrant and diverse passive house community, and to a much, much larger pie!




Ten years after

Hi folks, this is Mike Knezovich, also known as Mike #2. (PHIUS has a Mike problem.) I pitch in here on communications, conference, and, like everyone does in a small organization, whatever might need done. Anyway, Katrin’s in Pittsburgh for CPHC training at CMU, and is loaning me the Klingenblog space to wax a little nostalgic. Hope you enjoy.

A little more than 10 years ago, my wife and I took a frigid winter walk from our vintage (as in older than dirt) house in Urbana, Ill., to a little downtown bar called The Embassy. A good band was playing that night, and the place was packed. Friends waved us over, and in turn introduced us to their friends from out of town, and invited us to sit with them.

Raising the TJI-framed walls for Smith House.

One of their visiting friends was Katrin Klingenberg, an architect who lived and worked in Chicago. She had this idea to build a proof of concept for something called a passive house and was scouting for an empty lot–knowing land would be a lot more affordable in East Central Illinois than Chicago.

I was editor of an alt-weekly newspaper in town and started grilling Katrin. With healthy skepticism. But she wasn’t talking pie-in-the-sky bleeding edge technology like a magical yet-to-be-developed hydrogen fuel cell that would sit in the back yard.

Superinsulation. Airtight envelopes. Energy recovery ventilation. Triple pane windows. Passive solar. I’m a journalist by training—building science ain’t my forte. But I understood this stuff. And I figured if it made sense to me, it probably would make sense to a lot of other people, too. And that this might be a great story. I got Kat’s card, and later, when she and her crew got the slab for Smith House in the ground, I attended the groundbreaking party, and I got a nice feature for my paper.

During the summer months, vegetation on the trellis provides nice shading.

PHIUS staff celebrated the 10 year anniversary of the groundbreaking for Smith House just last week with an autumn cookout. And it brought to light just how much has changed in 10 years.

Urbana is now home to seven passive houses, three of them affordable housing projects built in partnership with the City of Urbana. More than 800 folks have taken the PHIUS CPHC training, with better than 400 earning CPHC status. Dozens of projects have been certified, and more than a hundred are in the pipeline.

Established institutions—like the U.S. Department of Energy, RESNET, Building Science Corporation and Fraunhofer IBP—that once were as skeptical as I was about passive house now see the value.

Years after writing the newspaper story I was recruited to the Ecolab and later the PHIUS boards. And a couple years ago, I joined PHIUS –at that time PHIUS was founders Katrin and Mike Kernagis, plus Ryan Abendroth — at PHIUS as an employee. Since then it’s been a ride.

I was lucky back in the 90s to have a front-row seat at the birth of the Web; I see definite similarities.

A peak inside from the loft.

Technologies once reserved for elite technocrats being democratized. Tremendous excitement. Constantly changing technology and changing assumptions. A feeling of infinite potential alternating with fear of losing steam. New players. Intense passion and competition. A need for open, adaptable standards and technologies that will help accelerate—not impede—growth.

During our conference in Denver, the sense of busting out was palpable. Passive house principles are on the verge of going from being a boutique program with a cultish following to something that will soon be commonplace. I feel proud and privileged to be along for the ride.

Thank you all for continuing to push. And though I can’t design or construct buildings, I’ll do my small part. I mean, I know a good story when I see one. And I think this one’s just getting started.

Mike Knezovich

The standard: Less energy, less pollution, more comfort.

I’ve been on the road a lot lately but let me thank you again for your thoughtful contributions and the

Solar radiation exposure is one factor that differs dramatically between Germany and the US. (National Renewable Energy Laboratory, European Commission)

healthy debate sparked by my first blog post, “15kwh is Dead, Long Live 15kwh.” In the post I put forth PHIUS’ plans to modify the passive house standard to address the specific climate and market needs of the North American market. A quick summary of the changes and their value:

  • Modifications will be based on the first and only large-scale analysis of passive house buildings in the United States and Canada – the 100+ buildings certified/under review by PHIUS.
  • They will address the substantive and reasonable critiques (such as the small-home penalty) of leading building scientists in North America like John Straube, Marc Rosenbaum, and Martin Holladay.
  • They will safeguard the high quality for which passive house is known by acknowledging

    View Marc Rosenbaum's presentation on passive house in the United States from the 2011 North American Passive House Conference

    fundamental differences (e.g., building in high-humidity zones presents unique quality challenges).

  • Modifications will calibrate envelope improvements more precisely for each climate and will be more cost effective than the one-size-fits-all approach. They will improve cost effectiveness in colder climates while maintaining comfort and quality of the envelope. And they will actually tighten the standard in climates where there is opportunity for more stringent targets.

The post touched off a great deal of constructive discussion and supportive comments – many folks expressing support for an idea they believe was long overdue.

Understandably, the prospect of change also caused some angst. Recently, a petition was circulated asking folks to sign-on in support of maintaining a single numerical standard associated with the term passive house. I fully understand the response – years ago, I might have signed on myself. But since then, based on the collective experience of passive house consultants who have designed and constructed projects across the continent, it’s become clear that adaptation is critical.

It’s also become clear that we at PHIUS need to get better at explaining the rationale for the modifications that we’re proposing and how they will help propel the market forward while maintaining the core principles of passive house.

To that end, I’d like to respond to some of the concerns and ensuing discussion around the petition mentioned earlier.

Let’s start with a sentiment expressed in a Green Building Advisor article related to the petition topic:  It was expressed that the “beauty of the standard is its purity.”  Purity implies uniformity, and my intended point is that 15kwh is not a universal truth, and therefore not practical for all climate regions.  The rigor of passive house is universal.  In the US, 15kwh is rigorous and practical in the Pacific Northwest  but hat’s not the case in most of the other North American climate zones.

By the same token, in some areas of the United States – Southern California, for example – it’s technically and economically practical to do better than 15kwh.  And it’s worth reiterating: adjusting the standard will allow us to do away with the small-house penalty (that being that it’s actually easier to achieve 15kwh in a larger structure than a small one, thereby presenting an incentive to build larger).

As mentioned in the first blog post, other parts of the world have already concluded that 15kwh is not universal. This is really not a new development.

More important, is the suggestion that modifying the standard creates market confusion. Three points argue against this being a concern:

1. Passive house is not a brand. Passive house is a generic term for structures that require little or no actively generated energy for heating and cooling. Put another way: “Passive house” is the equivalent to “hybrid automobile.” Car manufacturers now make their versions with their brands.

2. Passive house applies to the principles and practices – which are universal – required to build passive structures. Many of them — superinsulation, airtightness, energy recovery ventilation, managing solar gain — originated in the United States and Canada. They don’t belong to anyone. They are not brands. And they are available to all designers and builders who want to learn to apply them. They remain intact and powerful regardless of any number.

3. As more competitors arrive in a growing market wishing to offer passive house products clear branding of different passive house products (different trainings, quality assurance protocols or standard variations) is important to avoid confusion in the market place. PHIUS has differentiated its product by creating the PHIUS+ program.

Market size is a bigger concern. Passive house has come a long, long way in the past several years. But the market is still tiny. The imperative is to grow the market. And it will not grow if we adhere to a standard that isn’t practical in large swaths of the continent.

By making the standard applicable across the continent, and teaching professionals how to make passive house work where they work, we can help passive house principles go mainstream here in North America. We can make passive house principle best practice. And that will achieve all of our ultimate goals: Less energy, less pollution, more comfort. All thanks to passive house.


15kWh is dead. Long live 15kWh.

Hi Everybody:

Welcome to my brand new blog! I hope to keep you updated on the progress of Passive House and PHIUS, and to spark constructive discussion along the way.

On that note, I’d like to start this blog by addressing what we at PHIUS think will be the central issue for Passive House in 2012: fine-tuning the Passive House standard’s certification criteria, which were developed for the central European climate and market, to the unique climate and market needs of the United States and Canada.

Having evaluated five years of data from PHIUS’ portfolio — including more than 100 reviewed and/or certified projects of varied building types in the United States and Canada (thanks to the good work of the Passive House community) — we came to the conclusion that it’s time to:

  • Allow for a modification process to the rigid annual heating and cooling requirement of less or equal to 15 kWh/m2yr or 4.75 kBTU/ft2yr for the North American continent’s more extreme climates.
  • Define what has been missing all together so far – a stringent requirement for the third load which is the significant energy consumed in North America for dehumidification.

This idea that we need to adapt the standard to various regions has taken root around the world from domestic energy experts like Martin Holladay, Alex Wilson and Marc Rosenbaum to Passive House groups from other countries, like the Swedes. From our perspective, we do not feel that this adaptation guts the value of Passive House.  Instead, the goal is to introduce a new balancing act into the standard.

On the one hand, we need to let go of the illusion that there is a god-given magical number that can cost-effectively be adhered

Average solar radiation exposure is just one factor that differs dramatically between Germany and the US. (National Renewable Energy Laboratory, European Commission)

to worldwide. (The notion behind “15 is dead.”) In North America, in some DOE designated climate zones (specifically, top 5 and up and bottom 3 and down), the cost of meeting the mark is problematic. The added expense required to hit 15 is not recoverable over the life of the building.

On the other, we need to maintain the value of having a single baseline. (“Long live 15.”) The first 100 projects or so have indeed validated this benchmark as an appropriate design starting point for excellence in high performance building in North American climates.  The baseline builds into the standard a necessary rigor and elegance that gives the brand its strength.

The PHIUS Proposal

PHIUS is proposing to the PHIUS Tech Committee — composed of industry and policy leaders from the United States and Canada — to leverage the PHIUS dataset of 100 buildings, and to solicit feedback from the consultant community to create a new protocol that will allow Passive House professionals to determine practical modifiers to the standard to address climate, small home and retrofit scenarios. This new protocol would be used to determine the acceptable modification ranges for:

  1. Additional peak load allowances (heat, cooling, latent) per climate other than the cool moderate reference climate.
  2. Annual space conditioning requirements (heating, cooling and dehumidification) that follow from acceptable higher peak loads per climate other than the cool moderate reference climate.
  3. Annual source energy requirements. Based on the new annual requirements per climate other than the cool moderate reference climate.
  4. Airtightness criteria that will have to be re-evaluated based on climate; hygrothermal criteria might have to be added as well.

By introducing this protocol into the standard process, we start with the baseline design of 15kWh for a climate dominant space conditioning need (might be heating or cooling or dehumidification). It is business as usual from here. If you meet the governing energy metric in a cost effective way you are done. Congratulations!

If you find yourself in a climate that is more extreme, you will need to benchmark the economic benefit expectations. Using the new protocol, the level of insulation can then be fine-tuned within a small range of above or below the energy metric of 15kWh without sacrificing the quality and comfort criteria. Tuning down the conservation level in return fine-tunes the annual energy requirement specific to each project without having to resort to prescriptive measures, possibly wasting savings potential.

In this manner a new Passive House balancing act is achieved – 15kWh remains the only fixed criteria, while deviations to both sides are allowable within clearly defined parameters.

We envision this to be a simple evaluation process to determine cost-effectiveness that will not add significantly to the consultant’s workload or complexity of the design tasks. The recently announced PHIUS+ certification program — that introduces a level of quality assurance into the Passive House standard — can also be used to assure that all building science and quality criteria are upheld regarding this new protocol.

From Movement to Mainstream

Addressing the issue of modifications is a pivotal moment for high performance building in North America! Its time has come because we now have the dataset necessary to make these adjustments. PHIUS Tech Committee evaluation of over 100 projects represents the first study of an unprecedented volume of data on implemented Passive Houses in North America.

It’s also a pivotal moment because we are proposing a departure from a single one-size fits all international standard. We welcome everybody who would like to contribute to this effort.

This proposed shift of course will not happen overnight. There is a lot of work to be done.  It will be a careful, collaborative process driven by the experience and data gathered from real-world experience. I’ll be providing updates here, and PHIUS will provide updates via its e-newsletter and Web site in the next several months.

This progress is very exciting to me! I have been waiting for this for a while. We are finally tackling the contradictions that we all have been struggling with and it seems we are about to solve them.  In the process, I look forward to your comments and input — I hope you’ll use the comments feature (just click on the little bubble below) to weigh in!