PHIUS, Universities Partner to Train Emerging Passive Professionals

A feverish buzz builds in Alison Kwok’s University of Oregon classroom as students scramble to
complete final details of architectural elevations, double-check load calculations, and precisely
label drawings.

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This cohort of aspiring practitioners join a growing number of design students getting a jump start on their sustainable design careers by obtaining CPHC credentials while still enrolled at their institutions. To date, five institutions have formed partnerships with PHIUS to provide CPHC training: University of Oregon (OR), Miami University Ohio (OH), Prairie View A&M (TX), Ryerson University (ON), and Ball State University (IN). Most students who earn CPHC in school are practicing with firms within a year.

The CPHC curriculum and modules are largely the same as the weeklong trainings PHIUS regularly provides, with some important modifications. Professor Kwok sometimes opts to invite professionals as guest lecturers to cover content like WUFI modeling, while instructing on other items like assembly calculations of details herself (she is co-author of Passive House Details, with Donald Corner and Jan Fillnger). Other faculty instructors use the culminating product—developing a PHIUS+-compliant design—as more of a collaborative studio project than an individual take-home. This applied learning allows students to iterate through the design process while allowing collaboration, guidance, and peer exchange.

“They were motivated to learn the material again and were appreciative of getting into the depth that the PHIUS materials offered. The opportunity to become a Certified Passive House Consultant through a course tailored to their schedule was incredible!” said Professor Kwok.

These emerging professionals are already applying their building science knowledge and skills to great impact, while building portfolios and relationships with industry veterans.

The Race to Zero National Student Design Competition was one recent venue where the rising stars of sustainable design were able to really shine. This annual contest began with 84 teams from 68 institutions spanning eight countries, all vying for the best project in one of five categories: single family detached (suburban/urban), single family attached, small multifamily, and elementary school. The finalists were invited to NREL in Golden, Colorado this spring to present their projects before peers and distinguished judges (including PHIUS Executive Director Katrin Klingenberg).

Four of the finalist teams—Prairie View A&M, Miami University, and Virginia Tech—were led by students who had earned the CPHC credential through their university. Other teams, such as IIT, were supported and mentored by established CPHC professionals.

We’ll be featuring more stories from emerging CPHC professionals in the coming weeks. And be sure to join us in Boston for the 13 th Annual North American Passive House Conference, where Race to Zero winners will be presenting on their winning submissions.

PHIUS Joins US, EU Delegates to Tour Affordable Passive Buildings

On a sweltering hot and humid summer morning last week in Washington DC, PHIUS staff joined community development and design professionals from both sides of the Atlantic on a tour of sustainable social housing. The visit to Weinberg Commons, the first affordable multifamily retrofit project to earn PHIUS+ certification, capped the weeklong DC Energy Future Exchange Tour, organized by the Ecologic Institute.


The tour was led by Koray Aysin of HousingUP with Donna Rosano of Zavos Architecture + Design and Matt Fine, CPHC (formerly with Zavos). The guides described in detail the challenges and creative approaches they applied to renovate a dilapidated group of garden apartments into healthy, dignified, affordable homes for families of limited means—while also achieving ambitious energy and environmental targets. Because the developer, Housing Up, also pays the utilities, they had an incentive to invest in the building’s energy efficiency, knowing that the benefits would exceed the costs down the road. Some of the strategies the team used to hit stringent PHIUS+ energy targets included:

  • Specially designed window boxes that block solar heat gain while allowing natural light to enter the dwelling areas
  • Outboard insulation applied between vertical joist, a creative approach to a structural challenge


  • Energy recovery ventilation that reuses energy from indoors to pre-heat or cool thefresh air stream
  • Exceptional air tightness of 0.58ACH 50. This result is remarkable in new construction, and even more difficult to achieve in an existing building
  • A Variable Refrigerant Flow system that allows different sides of the building to heat and cool simultaneously. Due to superior insulation and air-tightness, all twelve units in the building are served by just one 2 ½ ton condensing unit—typical of a large single-family house.
  • Solar hot water panels and a basement storage tank; this results in a 40% cost savings
  • Rooftop solar electric panels developed by a third party, which sells back to the apartment at a rate 50% lower than grid purchase


Attendees were also able to see passive performance in action. While the tour started on a hot, loud street, discussion continued in the cool and quiet of the community room, thanks to the well-executed features. Here, participants learned about the financial aspects of the project. Financing sources included federal Low Income Housing Tax Credits, local housing funds from DC DHCD, funds from the DC Department of Behavioral Health, and philanthropic support.

Check out our Multifamily Resource page for concepts and case studies applying PHIUS standards to affordable housing. Then sign up to join us in Boston on September 20 for a pre-conference workshop with leading practitioners in design and community development.

Celebrating Summer Solstice in Chicago

Wednesday night, dozens of local designers, builders, and residents gathered to see how passive principles are applied in projects—and how they can give us a jump start on a clean energy future. PHAUS’ Chicago Chapter organized an in-depth guided tour of Tierra Linda, a PHIUS+ project currently under construction in Chicago’s Humboldt Park neighborhood. This affordable 6-unit building, developed by LUCHA, is vying to be the first PHIUS+ multifamily project in Chicago. It also shows how good design is the first step in making the sun our primary source of power.


So, how far does solar power go? Technically, energy from the sun, our friendly fusion reactor, travels about 93 million miles, or 7 light-minutes, to reach Earth. However, if you want to know how far solar power will go to meeting your home, business, or community’s energy needs and sustainability goals, you need to start with some critical questions and concrete examples.

As an energy efficiency evangelist, I often take umbrage when a news story says that a new power plant will produce “enough energy to power X homes.” Usually, that number’s about 750-1000 homes per megawatt, or 7.5-10kW per home. But how many GOOD homes would that same facility power?

To even approach numeric goals for climate, we need to address both supply and demand, numerator and denominator, at the same time.

This is where passive building comes in. By investing in the “passive” (i.e., nonmoving) parts of a building like walls and windows, we can significantly reduce the need for “active” systems like HVAC—and the energy to run them. The PHIUS+ standard sets cost-optimized energy targets based on local climate, building geometry, and occupancy.

If you start with minimal loads, it’s easier to meet them completely with clean energy. This is not complicated conceptually or practically. There is more opportunity to conserve energy in a building than to make it on the roof. The PHIUS+ limit on source energy makes sure that projects focus on efficiency first.

The table below compares the two scenarios PHIUS staff and the project team evaluated for the Tierra Linda project.

Annual Energy Use (kWh) 112,000 43,000
EUI (kBTU/sf/yr)                              39.3 16.8
PV needed for NZE                         86kW 22kW

If the project had been built to Chicago’s already stringent energy code, it would need a very large solar array. The extra 64 kW of solar would have cost $200,000 more. Even if there were room in the budget for that, there wouldn’t be space on the site! The team was able to eliminate equivalent energy use through passive techniques like insulation, air sealing, and energy recovery ventilation that will deliver comfort and savings to the residents—even on cloudy days in the depths of the Chicago winter.

Check back to the Klingenblog for more about how PHIUS+ is helping a clean energy future get made—even in the shade.


PHIUS vs PHI – Lessons learned webinar recap

Katrin Klingenberg, PHIUS Executive Director


Thanks to all of you who took the time to join us for last week’s webinar on the differences between the PHIUS and PHI passive house and building standards. Due to popular demand (we sold out within 3 hours of the original offering) we had to get a bigger “boat” and were eventually able to get everyone seated!

Clearly, there is a lot of interest in the topic.

Two passive building design/construction standards are available in the North American market: The PHIUS+2015 Passive building Standard certified through the Passive House Institute US and the Passivhaus Standard certified through the German Passivhaus Institute.

We presented the webinar in response to growing confusion about the differences between standards and questions about how the programs compare to commonly used energy standards such as ASHRAE 90.1. Other common questions: Are they simply “two flavors of the same thing” or are there more fundamental differences between programs? Which program is more commonly used in North America’s widely varying climates and why?

As we all make progress in mainstreaming passive building to significantly reduce carbon globally, one lesson has become clear: details matter! Different standards and modeling protocols offer significantly different guidance to designers seeking cost- optimized, high-performance buildings in their region.

The European standard and its design parameters for energy comprise one target for heating and cooling to attain an optimized design solution in all climates and cost structures worldwide. The PHIUS+ tailors and optimizes energy targets for both climate and cost, and does so for every individual location. The updated 2018 version becomes even more granular by taking occupancy and building typology into account.

Two very different approaches.

If you missed the live webinar, you can still learn more about the differences and modeling protocols: A recording of the webinar is now online!

Some of the questions that were asked during the webinar and could not be answered are posted below and if you have any other questions please send us an e-mail at

Thanks again to all of you who attended!


A selection of Questions posed during the webinar event, that could not be addressed live due to time constraints:

When will PHIUS+2018 come into effect? How long can we continue to use 2015 for projects in development?

PHIUS+2018 will be launched at the Annual conference this September in Boston. Teams can still use PHIUS+2015 until March of 2019.

What can we carry forward as a message from PHIUS & you to building code legislators?

We have put a lot of thought into making PHIUS+ a good standard for how much the building sector contributes to climate goals and/or the renewable energy transition, while also protecting occupant health and comfort. We have given it features to make it suitable for policymakers to incentivize. We can do feasibility studies for specific model buildings in specific climates to give officials a better feel for what PHIUS+ requires and delivers.

It is my experience that PHIUS at this time does not accept published efficiencies of ERV’s, and therefore the derated efficiency of ERV’s are not compatible with PHIUS certification requirements.

We accept 3rd-party ratings from AHRI, HVI, and PHI as well as our own product program – only unverified manufacturer data is derated. For building project certification there is not a hard requirement on recovery efficiency for the ventilation, but yes, in some climates it will be hard to meet the other performance criteria without a good H/ERV.

Can you expand on the adaptation aspects of passive house for the changes which are observed and expected in climate?

Right now, our certification is based on TMY3 climate data, and will update when newer data becomes available. Although predictive future TMY climate data sets exist, these are not used for certification. Even so, the performance upgrades required to meet our criteria should provide resilience benefit against weather extremes and utility outages. Resilience and adaptation to changing climate can be evaluated in a different way, more focused than modeling a typical year for predicted energy performance. We are working on a form of resilience assessment for that purpose.

Followup comment by another attendee: I took the climate question to mean: if standard is zone-variable, can we on top of that adapt to how existing zones are shifting to becoming one zone warmer. 

We are working on calculations that would generate climate data taking possible changes into account.

Wasn’t PHI’s cost-optimization based on integrating ventilation into the heating ducts and not cost of PV?

The idea was to improve/invest in the envelope to a point so that a typical heating system, and the cost associated with it, could be eliminated. The now minimized heating system could be integrated in the ventilation supply air stream using the same fan and ductwork for delivery. In Germany, eliminating the heating system supposedly made up for the additional cost to improve the envelope. In the U.S., because ducts and furnaces are relatively cheap, that strategy does not net much if any savings after one adds the HRV. PHI did not include cost of PV at the time because it was cost prohibitive. In the U.S. today PV is no longer cost prohibitive and at some point becomes competitive with insulation. Yes, the point was that in the U.S., because ducts and furnaces are relatively cheap, said integration doesn’t net much if any savings after you add the HRV.

Has E-Quest been calibrated against measured building performance for a large sample size of buildings?

I would assume so, it is widely used for code compliance modeling.

Is there a bigger sample size of monitored data on single family homes like the one in Oregon?


Is there any measured data to correlate with the modeling comparisons on Slide 27?

The NYSERDA study was on model buildings not actual, so we can’t get a direct comparison in that case.

In the future will there be more resolution than the ASHRAE climate zones for space conditioning criteria?

In all likelihood yes.

Going back to the financial graph, would you say that solar thermal is pretty incompatible with PHIUS or could it still be useful in certain climate areas?

At this point it appears not to be very cost-effective, but it could still have a resilience benefit in some climates. System complexity works against resilience, and climates that require freeze-protection tend to have more complicated systems.

Message from the Executive Director

Katrin Klingenberg, PHIUS Executive Director

Katrin Klingenberg, PHIUS Executive Director

Congratulations PHIUS professionals: thanks to your hard work, 2017 was perhaps the community’s best year ever! Together, in what was in other realms a tumultuous year, we maintained our focus and commitment to make high-performance passive building the mainstream market standard and best practice on the path to zero energy.

By the end of 2017, more than 1500 families now enjoy the benefits of buildings that are safe and comfortable for people and the planet. The buildings are thermally comfy, provide constant healthy indoor air, maintain safe living conditions during outages, produce super low cost utility bills, and are built at affordable costs. And they produce either zero CO2 or tiny amounts our planet can handle.

That is leadership in the most excellent way, urgently needed progress and really, really good news!

2017 highlights at a glance –

  • By all measures, PHIUS+2015 is the most successful passive building system in North America in 2017!
  • Under a previous grant and longstanding efforts, PHIUS jump-started the multifamily trend that continues to go strong. To maintain that growth, PHIUS received a grant from the Illinois Clean Energy Community Foundation to facilitate commercial certification protocols and uptake.
  • The 12th Annual North American Passive House Conference in Seattle was a huge success—a point of particular promise was that international sessions and keynotes showed global interest and relevance of PHIUS+2015 in other global regions.

    Signing cooperation agreement between PHIUS & PHIJP

    Signing cooperation agreement between PHIUS & PHIJP

  • PHIUS+ will soon be available in Japan—details of the collaboration with the Passive House Institute Japan (PHIJP) will soon be announced.
  • Research highlights:
    • PHIUS+2018, the scheduled update and evolution of PHIUS’ climate specific standard, is nearly ready for release for public comment. (Learn more at the Intro to PHIUS+2018 webinar on February 15)
    • Monitored data for the first PHIUS+ certified and quality assured multifamily projects match modeled performance predictions by +- 7%–proving we’re on the right track with PHIUS+ processes and tools.
    • PHIUS and Rocky Mountain Institute partnered to work under a DOE grant for retrofit research.
    • The Industry Advisory Council progresses with proof of concept of and all- climate monitoring project, funding installations in multiple zones.

In 2016, the Canadian Pembina Institute predicted exponential growth in the passive building sector. Their graphs showed that PHIUS certified the vast majority of all passive projects in North America up to that point and was generally on a trend to more than double certifications each year, as PHI certifications were declining.

In 2017 PHIUS met and slightly exceeded projected certifications for the year: Certifications more than doubled compared to 2016. PHIUS certified all but 1 passive building project in all of North America in 2017! And this year 100% of all certified projects had PHIUS trained professionals on the team. CPHC®s, PHIUS® Builders and PHIUS® RESNET Raters/Verifiers will continue to anchors of nearly all teams certifying projects.

This is a great endorsement of PHIUS+2015 certification: Climate specific design methodology assures appropriate thermal comfort, cost optimization assures avoiding pitfalls like over-investment in the envelope, and industry-standard quality assurance protocols endorsed by our partner the DOE eliminates risk of building failure. PHIUS+2015 has proven itself as the industry’ leading passive building system.

Beach Green Dunes in Queens, New York

Beach Green Dunes in Queens, New York

In 2016 we were thrilled to celebrate the milestone of reaching over 1 million square feet of PHIUS+ certified and pre-certified projects across 900 units – and families – nationwide. It took five years to reach that milestone. In 2017 alone we nearly doubled that square footage, reaching 1.75 million square feet of PHIUS+ certified and pre-certified projects across 1,500 units. Wow!

2017 has continued to be a great year for multifamily passive building projects, led by uptake seen in the affordable sector. We are very proud of the great strides the community has made in bringing the benefits of passive buildings to more people than ever before—and to the people who need it most.

In 2017, a marquee multifamily project—Steve Bluestone’s Beach Green Dunes in Queens, New York, became the first mid-rise project in the country to be completed. Its 101 units are now occupied and the project started winning awards right out the gate. It is not only passive, but also uses onsite PV and CHP to generate one third of projected energy consumption. It’s a model project illustrating the path to zero energy and emissions. New projects in the pipeline are getting even bigger: 425 Grand Concourse, a 28 story affordable hi-rise has completed planning and is scheduled to break ground in 2018. Many housing agencies across the country continue to support affordable multifamily developments.

The really good news: The Pennsylvania Housing Finance Authority (PHFA) was the first affordable housing agency to recognize and reward passive buildings. A study of projects spurred by the PHFA, as well as other affordable MF projects around the country, shows costs coming in at 0-2% additional costs over conventional projects. The cost-optimized targets are working!

RMI Innovation Center Basalt, CO -- PHIUS+2015 Certified, PHIUS Source Zero Energy Certified

RMI Innovation Center Basalt, CO — PHIUS+2015 Certified, PHIUS Source Zero Energy Certified

Commercial developments are also being submitted for PHIUS certification. The RMI Innovation center was completed in 2016, winning Best Overall Project in the Annual Passive Design Competition for that year. RMI’s leadership spurred other commercial project teams to conduct feasibility studies, and several are in various states of completion: A planned office hi-rise in Chicago, an administrative building in Spokane, Washington, with a commercial kitchen, a church in Hudson Valley, New York, and multiple school buildings are underway, aiming for passive even for zero energy. (Learn more about the RMI Innovation Center at the Commercial Webinar Series kick-off presentation on February 7)

Following the multifamily approach, we look to lead a similar spike in adoption in the commercial sector. Thanks to a generous grant from the Illinois Clean Energy Community Foundation in 2017, we are in the process of assembling an online Commercial Resource Center; a companion to the MacArthur Foundation funded Multifamily Resource Center that we launched in 2016.

The Commercial Resource Center will serve as an information hub for developers, policymakers, and investors in the design, financing, and execution of commercial passive buildings. We have demonstrated with projects such as the RMI Innovation Center in 2016 that the PHIUS+ Passive Building Standard can be more cost-effective than business-as-usual commercial construction practices to reach zero and positive energy targets. The Commercial Resource Center will help to make even more of these projects a reality.

The encouraging growth in the commercial and multifamily sectors was fully illustrated during sessions at the 12th Annual North American Passive House Conference in Seattle. The conference sold out for a third year in a row and sparked an advanced level of discourse, especially in the building science field.During our 3rd Annual Design Awards Ceremony the Best Overall Project prize was awarded to Elm Place, an affordable multifamily housing development in Burlington, Vermont. A successfully certified PHIUS+2015 project, it elegantly proved the cost effectiveness of the design targets: The project was realized at a 2% cost premium in climate zone 6! Congratulations to CPHC Chris West and his team for this outstanding project! (Learn more about Elm Place at the Developers Webinar Series presentation on January 30)

Milton, VT -- PHIUS+ 2015 Certified

Elm Place, Milton, VT — PHIUS+ 2015 Certified

Internationally, building scientists and government organizations have taken notice of the PHIUS’ unique, climate specific approach, and approached PHIUS about potential collaboration. In August of 2017, Mike Kernagis and I went to Tokyo to keynote the kick-off symposium of the Passive House Institute of Japan (PHIJP). There we signed an international collaboration agreement between PHIUS and PHIJP. In 2018 we will work together to generate cost optimized design targets for the climates of Japan and to translate training materials and certification protocols. Following our keynotes in Shanghai, China, in November of 2017 we were invited to send a keynote presentation on our work in the US to be presented to the attendees of the 4th Chinese Passive Building Summit. More international collaboration talks are to follow in 2018.

In conclusion, a few more notes on research: PHIUS is committed to excellence and continued improvement of the design methodology and standards. We recalibrate the standards regularly to make sure that they are optimized to changing market and climate conditions, as well as advances in components. PHIUS+2018 will be released soon for public comment and adoption. (Learn more at the Intro to PHIUS+2018 webinar on February 15)

Our goal is to have the effort continuously informed by hard monitoring data from certified projects. That effort has been launched by the Industry Advisory Council, a group of leading passive building component manufacturers. In 2017, thanks to the IAC, we selected 6 pilot projects, representing key typologies and climate zones. We finalized appropriate monitoring protocols and selected equipment manufacturers and installation is underway at the first projects. The pieces are now all in place and we will use our pilot project experience to streamline and replicate the monitoring processes, with end goal of making it a fairly routine option available during the PHIUS+ certification process.

Under a DOE grant, PHIUS and RMI will work to provide guidelines and practices for exterior scalable retrofits of projects to achieve zero energy buildings. Work on this project will kick off in January in Boulder, Colorado.

This is all thanks to all of the partners, certified professionals, manufacturers and other supporters who help us advance passive building each and every day. We have accomplished so much already, but there is still much great work left to do. Looking forward to what I believe will the best year ever!

Katrin Klingenberg
Executive Director, Passive House Institute US | PHIUS