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Instructor Bios

Ryan Abendroth


Ryan Abendroth is an experienced Certified Passive House Consultant (CPHC®) and the former Certification Manager at Passive House Institute US (PHIUS). He has worked on hundreds of passive house projects including small residential designs and student projects to mid-sized commercial and non-profit developments, and he has been at the forefront of research and design in passive houses for almost a decade. His first passive house experience was with Team Illinois in the US Department of Energy's Solar Decathlon Competition in 2009, where the team took Second Place overall. Abendroth is a PHIUS Certified CPHC® Trainer and a member of the PHIUS Technical Committee, the PHIUS+ Rater Program, and advanced tutorials on topics related to passive building construction.

Abendroth also serves as the Principal of Passive Energy Designs LLC, a St. Louis, Missouri-based consulting firm specializing in achieving built high-performance and low-energy buildings that meet the passive house standard. He holds a Master of Architecture and a Bachelor of Science in Architectural Studies from the University of Illinois at Urbana-Champaign. Currently, Ryan is a lecturer at the Sam Fox School of Design and Visual Arts at Washington University in St. Louis where he teaches both graduate and undergraduate courses focused on the impacts of climate, site, energy, detailing, and building information modeling (BIM) on the built environment. Previously he taught at the Rhode Island School of Design as both a Visiting Lecturer and Critic and has acted as a passive house consultant for Kansas University’s 5th year design-build program, Studio 804.

Dave Brach


Dave Brach is the owner of Brach Design, an architecture firm based in Salt Lake City, Utah that specializes in passive and net zero energy design for residential and small commercial buildings. He has been involved in the design and construction industry full-time since 1993 as a carpenter, cabinetmaker, designer, and licensed architect, and is also co-owner of a licensed general contracting business. Brach designed the first Certified Passive House in the West in 2009.

Brach has a degree in anthropology from the University of Notre Dame, and a Masters of Architecture from the University of Illinois at Chicago.

Terrry Brennan


Terry is a building scientist and educator. He is on the editorial boards of Environmental Building News and Heating Piping and Air Conditioning Magazine. He currently chairs the U.S.A.C.E committee developing new air leakage protocols. Past work includes consulting on a research project to restore three homes in the Seventh Ward of New Orleans after Hurricanes Katrina and Rita, teaching healthy housing courses for the National Center for Healthy Housing and working on a research project to study unplanned airflows in commercial buildings in New York State. He is a member of ASHRAE 62.2 Ventilation and Air Quality Committee and served as consultant to the National Academy of Sciences Committee on Dampness and Health in Buildings. He holds a Bachelors degree in Physics and a Masters degree in Environmental Studies.


Adam Cohen


Adam Cohen leads the PHIUS Certified Builder Training program in conjunction with Mike Kernagis and Dan Whitmore. 

As an active design/builder and green building expert, Cohen is a leading North American passive house practitioner whose innovative work on market rate delivery of commercial high-performance building has made his expertise sought-after for projects across North America. His leadership in commercial passive house design has made him a sought after speaker, consultant, and teacher of advanced courses in ultra-low energy design. As a recognized national leader in the passive building movement he has presented technical papers at both national and international passive house conferences including those of Passive House Institute US (PHIUS), Passivhaus Institut, and Passive House Northwest.

Cohen studied commercial design and construction in the United States and Europe with leading architects and builders. As one of the first Certified Passive House Consultants (CPHC®) in the US, his deep knowledge and advanced practice in commercial passive building design and construction are widely recognized by his peers, as evidenced by his appointment as Vice Chairman of the PHIUS Technical Committee.

Cohen currently serves as a board member of Yestermorrow Design Build School and the Renewable Energy and Electric Vehicle Association. At Yestermorrow Design Build School he also serves as adjunct faculty and teaches courses on alternative building and the business of design/build. He previously served as a board member of Roanoke Clean Valley Council, the Roanoke City Clean and Green Committee, and the Green Schools Committee of the US Green Building Council (USGBC) of Southwest Virginia.

Prudence Ferreira


Prudence Ferreira is a Partner in Passiv Science, a consulting partnership focused on large scale multifamily, commercial, and institutional passive building projects. She heads the firm’s energy modeling team and has unique expertise and experience with WUFI® Passive. Her credentials include LEED AP BD+C, LEED for Homes Rater, GreenPoint Rater Certified Title 24 Energy Analyst, Hygrothermic Analyst, and Certified Passive House Consultant (CPHC®). She is a PHIUS Certified CPHC® Trainer, core curriculum developer, and exam author for Passive House Institute US (PHIUS), and teaches the CPHC® training program and advanced passive house technical workshops around the US. She helped author the CPHC Exam, helped train over 500 CPHCs, and is a core contributor to CPHC training curriculum. Ferreira also teaches Hygrothermal Analysis around the US as a certified instructor for the Fraunhofer Institute for Building Physics and Oakridge National Lab’s WUFI-ORNL program. She plays a key role in the partnership between the Fraunhofer Institute for Building Physics and PHIUS in developing, beta testing, and field verifying a new energy and hygrothermal analysis design tool specifically for passive, low and zero energy building design and verification.

Ferreira currently serves on the PHIUS Board of Directors, where she previously served as President, and as a member of the PHIUS Technical Committee. She also interfaces with USGBC national technical staff on the LEED for Homes and PHIUS+ Standard integration effort and inputs significantly continuing education program development. Ferreira is a founding member of the PHIUS Technical Committee and has consulted on 30+ passive house projects across 7 different climate zones.

Mike Kernagis

Instructor, PHIUS Chief of Operations

James M. (Mike) Kernagis was one of the first American builders to adopt passive building principles and build projects that meet the passive building energy standard.

In 2003, he and Katrin Klingenberg co-founded e-cological Construction Laboratory (e-colab) as a non-profit affordable housing developer in Urbana, Illinois to further investigate the feasibility of applying passive building principles in the United States. In 2005 he served as construction manager for the affordable housing units built to the passive building standard in cooperation with the City of Urbana.  

As interest in passive building grew in North America, Kernagis and Klingenberg oversaw the expansion of e-colab into Passive House Institute US (PHIUS) in 2007. PHIUS is now the leading passive building standard setting, research and information provider, training, and certification institute in North America. In his role as Program Director of PHIUS, Kernagis has overseen PHIUS operations, training, and membership programs since its inception. In 2012 Kernagis helped launch the PHIUS Certified Builder Training program, where he was instrumental in the development of its curriculum and continues to serve as a lead instructor for the program.

Katrin Klingenberg

Instructor, PHIUS Executive Director

Katrin Klingenberg designed and built the very first home in the United States built to the passive building energy standard. Her experience led her to co-found e-cological Construction Laboratory (e-colab) with builder Mike Kernagis in 2003 as a non-profit affordable housing developer in Urbana, Illinois to further investigate the feasibility of applying passive building principles in the United States. As interest in passive building grew in North America, Klingenberg and Kernagis oversaw the expansion of e-colab into Passive House Institute US (PHIUS) in 2007. PHIUS is now the leading passive building standard setting, research and information provider, training, and certification institute in North America.

Klingenberg has since designed and consulted on numerous passive building projects across North America’s varied climate zones. In her role as Executive Director of PHIUS she directs the technical and research programs of the organization. In addition to her executive role, she is also the lead instructor and director of curriculum development for the PHIUS Certified Passive House Consultant (CPHC®) Training program. Klingenberg earned the German equivalent of a B.S. in Architecture at the Technische Universität in Berlin, Germany, earned an M.S. in Architecture from Ball State University, and is a licensed architect in Germany.

Natalie Leonard, P.Eng


As the first Certified Passive House Consultant and Builder in Canada, Natalie is a recognized leader in the Passive House movement in Canada. Natalie founded Passive Design Solutions in 2009 - a design, build, and consulting firm that is dedicated to creating cost effective, elegant, practical, super-efficient buildings for the future.

Natalie has been delivering the PHIUS Builder Training in Canada since 2016. She brings her engineering background, hands on design and construction experience, and a practical, efficient approach to building. Natalie built the first certified single-family passive house in Canada and has now worked on over 60 passive house projects in Canada. Projects range from new small single family to large scale apartment buildings, renovations, and new construction.

Natalie also has been a board member of Passive Buildings Canada for 5 years and has recently joined the board of Solar Nova Scotia.

John Loercher


John is a CPHC instructor for the Passive House Institute U.S., Secretary of the Passive House Alliance — Hudson Valley chapter and Owner of Northeast Projects LLC. He is a Certified Passive House Consultant and holds a master’s degree in architecture from Parsons the New School. His firm, Northeast Projects specializes in Passive House design, high performance building envelope design and advanced energy modeling. It engages a wide range of work from single family residences, commercial projects, mixed-use projects, new construction and retrofits.

Maren Longhurst


Maren Longhurst, AIA, CPHC, is the Building Science Coordinator for Sam Rodell Architects, a firm with projects ranging from custom homes to institutional/commercial throughout the Pacific Northwest from Montana to the Puget Sound. Her interests include high performance architecture and building science, using site analysis along with thermal and spatial modeling to design beautiful, efficient buildings that perform reliably, elegantly, and simply.

John McCreery


John McCreery is a Certified Passive House Consultant (CPHC®) and professional architect. Spanning 35 years, his professional practice experience includes teaching and design with a philosophical emphasis on curiosity, humanity, ecology, context, consensus building, sociological planning, building performance, and daylighting. He founded his company What Art LLC in 2010 to place these ideas into architectural practice. 

McCreery has lectured nationally and internationally on the topics of sustainable design, state of the art educational theory and facility design, 21st-century school design, and Passive House Metric: Pathway to Global Energy Security. He is a recognized expert in educational design and refined environments for industrial processes.

Chris McTaggart

Instructor, PHIUS+ Rater Program Manager

Chris McTaggart is the QA/QC manager in support of the PHIUS+ Rater program and leads the PHIUS+ Rater and PHIUS+ Verifier training programs of Passive House Institute US (PHIUS). He also serves on the PHIUS Technical Committee. McTaggart is Co-Principal at Building Efficiency Resources (BER), a national third-party RESNET QA Provider working with independent rating companies throughout the United States. McTaggart brings a background rich in research, analysis and logic developed both through his professional experience and formal education at Michigan State University.

Shelly Pottorf


Shelly Pottorf (AIA) is a practicing architect and an Assistant Professor in the Prairie View A&M University (PVAMU) School of Architecture, located just outside of Houston, Texas. Shelly designed and implemented the School’s Minor in Sustainable Design and was among the first to pilot the CPHC training at the university level. Her research focuses on implementing PHIUS+ in hot and humid climates for social, economic, and environmental resilience. Through this work her PVAMU student teams have won numerous awards including two Grand Awards in the Department of Energy Race to Zero Competition and a COTE Top 10 Student Design Award.

Russell Richman


Dr. Russell Richman is Assistant Professor in the Building Science Group within the Department of Architectural Science in the Faculty of Engineering & Architectural Science at Ryerson University in Toronto. He has conducted research in building science and sustainable buildings since 1998. Dr. Richman plays a key role in the development and delivery of the Graduate Program in Building Science in the Department of Architectural Science. This program, unique in North America, combines the fundamentals of building science with the broad mandate of sustainable engineering and building design. Dr. Richman also serves on the Technical Committee of Passive House Institute US (PHIUS).

John Semmelhack


John Semmelhack is the owner of Think Little, a building science consulting firm based in Charlottesville, Virginia, specializing in building enclosure and mechanical system design for single-family and multi-family Passive House and net-zero energy homes in the mid-Atlantic.

Since 2007, Think Little has provided consulting, testing and inspection services for over 2,500 multi-family and single-family housing units, including several firsts – the first certified Passive House residence in Virginia as well as some of the first EarthCraft certified net-zero homes.

John is a certified Home Energy Rating System (HERS) rater and an EarthCraft Technical Advisor. John is also a CPHC® (Certified Passive House Consultant), is a member of the Passive House Institute U.S. (PHIUS) Technical Committee, and is a PHIUS Certified CPHC® Trainer (Certified Passive House Consultant).

Lisa White

Instructor, PHIUS Project Certification Manager

Lisa White has been with Passive House Institute US (PHIUS) since 2012 and currently serves as the project Certification Manager. She is also an instructor for Certified Passive House Consultant (CPHC®) and WUFI Passive software trainings. White holds a degree in Environmental Sustainability with a minor in Architecture from the University of Illinois at Urbana-Champaign, and she is currently pursuing her Master’s in Energy Engineering at the University of Illinois at Chicago.

In consultation with PHIUS Senior Scientist Graham Wright, White works on certification program development, reviews project designs and energy models to evaluate their qualification for PHIUS+ Certification, and provides feedback to project submission teams. She also provides consulting services on static and dynamic energy modeling in WUFI Passive, THERM modeling, and project planning specific to passive building principles. White has presented at numerous conferences and events, including the PHIUS Annual North American Passive House Conferences, the Affordable Comfort Institute national conference, and Facades+.

Dan Whitmore


Dan Whitmore is a passive house and enclosure consultant with RDH Building Science. He has worked in the construction industry since 1987 building, detailing and/or project managing a wide range of structures, from mountain cabins to law school libraries. As designer, builder, and CPHC® (Certified Passive House Consultant), he completed one of the first passive houses in Washington State in 2010. Since this time, he has consulted on and/or built more than twenty passive house projects primarily in his home region of the Pacific Northwest. Whitmore is also an Instructor at PHIUS, co-developer of the PHIUS Certified Builder Training program, Council Treasurer of Passive House Alliance US (PHAUS), and a founding board member of Passive House Northwest.

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