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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.

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.

Izumi Kitajima


Izumi Kitajima is originally from Japan. She works for Peabody Architects, a firm in the Washington DC area that specializes in sustainable and high performance homes and which has designed and consulted on a number of certified Passive Houses. She became a Certified Passive House Consultant in 2009, and joined the Board of the Passive House Institute Japan (PHIJP) in 2017 and serves as their U.S. liaison. She received her master’s degree in architecture from the University of Kansas, where she participated in the design-build program, Studio 804.

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.

Tony Lisanti


Tony lives in NJ just north of New York City. He has an Associate’s Degree from S.U.N.Y. in Internal Combustion Engine Engineering Technology, a Bachelor’s of Science in Mechanical Engineering from the Rochester Institute of Technology, and a Master’s of Science in Organizational Leadership from Mercy College.

His 34+ years of experience includes Mechanical/Electrical design with consulting firm, serving as a Maintenance Specialist and Account Executive with Con Edison Co. of NY, Inc, Director of Energy Sales and Service with Robison Energy and is presently Managing Director at Integral Building & Design, Inc. in Nyack, NY

As a Certified Home Energy Rater, certified over 2000 dwelling units for the Energy Star Program and completed HERS Ratings for IECC compliance, EPA Indoor airPLUS, DOE ZERH and PHIUS+. He continues to work with municipalities and the NY Dept. of State in developing higher standards for energy codes.

He previously served on the Board of Directors of the BPCA/NYS, Passive House Alliance - Hudson Valley Chapter, several RESNET working groups, the Rockland Business Association Green and Commercial Real Estate and Development Councils, and previously was Vice-President of the NEHERS. Since 2018 he has been QA/QC Manager for the Passive House Institute US.

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.

Dan Luddy


Dan is a mechanical engineer and building performance specialist with 12 years of multi-disciplinary
experience, including energy consulting and system evaluation for commercial new construction in
Seattle, New York and Boston. He has worked across many facets of HVAC design and high performance
building design. In particular, he is skilled in energy modeling and thermal comfort analysis. Dan focuses
on the integration of building envelope and mechanical systems to produce the best solutions for
efficiency and performance for the occupants. He has been a CPHC since 2014 and a Trainer since 2018.

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.

Sayo Okada


Sayo Okada was born and raised in Nara, Japan. She has been practicing architecture for over 15 years in Boston MA area, and has experience in a variety of projects including childcare, higher education, and housings. Sayo has been involved with the Passive House community since 2010, and involved in certifying projects for single family and multifamily projects. She is also working with PHIUS to establish Japanese climate specific Passive House standard and a CPHC course in Japan in collaboration with Passive House Institute Japan.

Sayo has a B.Arch. from the Wentworth Institute of Technology.

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).

Chris West


Chris got involved with the Passive House movement in the US in 2010 just after he returned to the US from a 10 year stint in the Netherlands, where he got a BS in Mechanical Engineering from the Hogeshool van Amsterdam.  Passionate about building energy use and building science, Chris started a small consulting firm, Eco Houses of Vermont LLC, which has been involved in a number of single family and multi family projects in and around Vermont, some of which have been honored by PHIUS with awards at various PHIUS Conferences.

During his time in the Netherlands Chris also taught Technical Drawing at the Hogeschoool van Amsterdam for six years. His love of teaching grew during this time and he was very excited to be accepted as an instructor for PHIUS.

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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