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Passive House Podcast
Passive House Podcast
Author: Matthew Cutler-Welsh, Zack Semke, Mary James, and Ilka Cassidy
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© 2025 Passive House Accelerator
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Interviews with the leaders, practitioners, and change-makers in the global Passive House movement. A production of Passive House Accelerator.
487 Episodes
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In this episode of The Passive House Podcast, Mary James interviews James Hartford and Juhee Lee Hartford of River Architects in Hudson Valley. The discussion covers the firm's focus on Passive House projects, mostly single-family homes with a mix of new constructions and retrofits. They touch on their first retrofit project affected by Hurricane Sandy, the evolving client interest in Passive House standards, and the firm’s growth from two to ten employees. They discuss the financial and practical challenges of Passive House projects, including material and energy considerations, involvement in advocacy through Passive House Hudson Valley, and the growing demand for such homes. They also highlight the benefits of prefab construction in difficult climates and the importance of builder experience. https://www.riverarchitects.com/Video of River Architects' Bank Lofts retrofit project: https://youtu.be/GHLC2xGM-ykBest of Retrofit: https://events.ringcentral.com/events/reimagine-buildings-retrofit/registrationThank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive House Podcast Matthew Cutler-Welsh sits down with Joseph Lyth an Associate Registered Architect, Certified Passive House Designer based in New Zealand. Joesph walks Matthew through his decision to build a passive house to create a healthier environment for his family. Believing that healthier, lower energy and affordable buildings are possible for everyone in New Zealand, at standard budgets. Lower Saddle Passive House Tāhekeroa: https://nzgbc.org.nz/case-studies/lower-saddle-passive-house-t%C4%81hekeroa
Matthew interviews Enda McDonagh, Certified Passive House Consultant and principal at Montgomery Sisam Architects. Enda studied and worked as Architectural Technician in Dublin where he developed a passion for detailing. In 2010 he moved to Toronto, Canada where he has worked at Montgomery Sisam ever since. His portfolio includes projects for the education, supportive housing, and mental health sectors. Montgomery Sisam is currently working on an affordable housing development in downtown Hamilton. All 24 of the studio apartments are being built offsite and the whole building will be Passive House Certified. Hamilton Passive House Modular Housing: https://www.montgomerysisam.com/project/hamilton-passive-house-modular-housing/ Passive House Stories: https://www.theguardian.com/lifeandstyle/2022/oct/08/passion-project-the-passive-house-that-raised-the-roof-on-sustainable-living-passivhaus https://homestylegreen.com/181-hutt-tomorrows-house-today/ https://connectingtoplace.org/sustainability/ https://mithun.com/project/the-bush-school-new-upper-school/ Info about upcoming events: https://passivehouseaccelerator.com/articles/passive-house-weekly-october-17-2022 Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this Episode of the Passive House Podcast Matthew interviews representatives of Ecological Building Systems, including Niall Crosson, the Group Technical Director, and Neil Turner, the UK Technical Manager. They discuss the company's inception 25 years ago, its growth, and its innovations in bio-based construction and air-tightness solutions. The narrative also details their training programs and market challenges, particularly regarding the advances in air-tightness and mechanical ventilation systems in the UK and Ireland. The episode highlights various sustainable products such as vapor control layers, natural insulation materials like wood fiber and hemp, and decentralized ventilation systems. Emphasis is placed on the educational aspect of their business, targeting both industry professionals and the general public through roadshows and training centers. Lastly, they underscores the importance of sustainable and energy-efficient building practices, reflecting the company's mission and the broader movement towards eco-friendly construction.https://www.ecologicalbuildingsystems.com/https://ukphc.org.uk/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive House Podcast co-host's Jay and Mary chat with Emily Mottram, founder of Mottram Architecture, about her architectural firm and her passion for building science and low-carbon residential architecture. Emily discusses her firm's focus on retrofits and new builds, explaining their approach to sustainable architecture using eco-friendly, bio-based materials. She shares insights on the complexity and importance of retrofitting existing structures, the challenges and benefits of panelized construction, and the holistic methods she employs to ensure the health and safety of building occupants. https://www.mottramarch.com/Best of Retrofit: https://events.ringcentral.com/events/reimagine-buildings-retrofit/registrationThank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of The Passive House Podcast host Mary James meets with Katie Schwamb, Managing Director at Building Energy Exchange (BE-Ex) to discuss emissions reduction and compliance with Local Law 97 in New York City. Local Law 97, sets carbon emissions limits for buildings over 25,000 square feet to help achieve near-zero emissions by 2050. Mary and Katie cover the importance of strategic planning, financial incentives, and challenges building owners face in complying with the law. Katie highlights Building Energy Exchange’s array of resources aimed at advancing energy-efficient, decarbonized buildings, including case studies, retrofit playbooks, and their Local Law 97 calculator.https://be-exchange.org/Best of Retrofit: https://events.ringcentral.com/events/reimagine-buildings-retrofit/registrationThank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of The Passive House Podcast, host Jay Fox talks with Andrea Michael, an architect from Love Schack Architecture in Bozeman, Montana. They discuss Andrea's comprehensive home retrofit, aimed at improving energy efficiency and comfort. The retrofit included air sealing, adding insulation, installing a heat pump, ERVs, solar panels, and more. The conversation highlights Andrea's journey from initial DIY efforts to a full-scale renovation, revealing significant energy savings and improved indoor air quality. The episode also touches on the challenges and successes of integrating sustainable building practices in Montana.https://loveschackarchitecture.com/See Andrea December 5th at Best of Retrofit: https://events.ringcentral.com/events/reimagine-buildings-retrofit/registrationThank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of The Passive House Podcast, host Mary James speaks with Kara Haggerty Wilson, Design Director at Onion Flats. Kara discusses the company's focus on scaling up deep energy retrofits. She highlights their journey from initial projects in Pennsylvania to more extensive work in Massachusetts, including the challenges and successes of projects like the 130-year-old Hano Homes retrofit. Kara shares insights on navigating site-built versus panelized solutions, the importance of detailed building scans, and the evolving interest in deep energy retrofits among developers. The conversation also touches on technological advancements and the complexities of integrating new systems into old structures.https://www.onionflats.com/https://passivehouseaccelerator.com/events/101-deep-energy-exterior-retrofits?date=2025-11-05
This week on the Passive House Podcast we welcome Ben Walsham, the founder and director of ARKATA, based in Brunswick, Victoria. Trained in architecture and now a registered NatHERS Accredited Energy Efficiency Assessor, Ben empowers architects—as well as homeowners, builders, and developers—across Australia to create homes that are not only energy‑efficient, but comfortable, healthy, and resilient With a background in residential architecture and on-site building, Ben witnessed first-hand the pressing need for better performance in homes. This inspired his transition into sustainability consulting and ultimately to launching ARKATA in 2023.ARKATA’s mission reflects Ben's philosophy: “Uncover the power of sustainability” through a human‑centered lens, where efficiency measures translate into tangible comfort and wellbeing for occupants.https://www.linkedin.com/in/ben-walsham-104188148/https://linktr.ee/arkata.au
In this episode of the Passive House Podcast, Ilka Cassidy and Kristof Irwin are at PhiusCon 2025, highlighting key sessions and interviews with industry experts. The conference explored a variety of themes including performance, purpose, and the power of community in the Passive House movement. Key takeaways included insights on air tightness, ventilation, innovative financing models, and the challenges and successes in scaling up Passive House projects. https://www.phius.org/phiusconThank you to Ikon Windows for sponsoring this episode of the Passive House Podcast! https://www.ikonwindows.com/ Thanks to Jennie Eber, Tom Bassett-Dilley, Kai Fast, Sayo Okada, Beth Campbell, Beverly Craig, Kazumasa Tsushima, Daiji Sato, and Alexander Gard-Murray for joining us!Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive House Podcast, Matthew Cutler Welsh talks with Matthew Crucifix, Director of Development at Stonewater, they discusses the organization's efforts in providing affordable and sustainable housing in the UK. Crucifix outlines Stonewater's expansive reach, managing around 40,000 homes, and their current focus on retrofitting existing homes to improve energy efficiency. Highlighting the financial challenges and solutions, including government grants and their in-house subsidy pot. He also delves into the specifics of their Passive House projects, like Cherry Grove, emphasizing the goal of building homes that are affordable, energy-efficient, and environmentally friendly. The conversation concludes with insights into the future of housing in the UK, stressing the importance of sustainable construction methods and energy resilience.https://www.stonewater.org/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive House Podcast, Mary James and Ilka Cassidy interview Tony Lisanti, managing director at Integral Building and Design and QA/QC Manager for Phius. The discussion delves into various rating systems for high performance and passive houses, focusing on the HERS rating method, its standards, and applications. Tony explains his extensive experience in the energy and engineering fields and how he provides certification services for numerous federal and state programs. He further details the process of becoming a HERS and Phius rater, emphasizing the importance of early engagement in the project, thorough QA protocols, and consistent communication between designers and raters. The episode also highlights case studies, including a modular senior housing project and a panelized straw system, illustrating the complexities and benefits of these high-performance building standards.https://www.phius.org/https://integralbuilding.com/https://collective.reimaginebuildings.com/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of The Passive House Podcast, join Jay Fox and Mary James as they dive deep into sustainable building systems with Greta Tjeltveit, a Building Science Consultant at 4EA Building Science and Board President of Passive House Northwest. Greta shares her inspiring journey from researching post-Katrina rebuilding efforts in high school to her current role, discussing her experiences and insights into the evolving fields of green building, building science, and Passive House design. They also explore topics such as the importance of early testing in Passive House projects, challenges of ventilation systems in the Pacific Northwest, and the impacts of wildfire smoke on indoor air quality. Don't miss this engaging discussion on the latest trends and innovations in sustainable architecture and Passive House certification. Join Greta this Wednesday: https://passivehouseaccelerator.com/events/101-balanced-ventialtion?date=2025-10-01https://collective.reimaginebuildings.com/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of The Passive House Podcast, join Ilka and Jay for their in-depth discussion with the members of the Reimagine Buildings Collective's innovative Summer Labs. The episode showcases the experiences and insights of various industry professionals who participated in these member-led groups. Featuring Paul Heron, Randall Anway, Lauren Shadid, Valerie Amor, Sandra Lester, Fabrizio Maso, Buck Moorehead, Lloyd Alter, Mark Attard, Rainger Pinney, and Mike Fowler.https://collective.reimaginebuildings.com/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of The Passive House Podcast, Mary James interviews Az Rashid Head of Design at Barratt London. Az shares details about Barratt London's focus on large-scale, mixed-use, residential-led regeneration projects within London, and their collaboration with Transport for London (TfL) to develop properties near transit lines. He discusses his journey from architecture to his current role and explains Barratt London's recent commitment to building all new homes to Passive House standards, including the anticipated benefits for residents and the environment. The episode covers their methodical approach to training, research, and development to achieve Passive House certification, as well as their plans to begin delivering Passive House homes by 2029.https://www.barratthomes.co.uk/new-homes/london/Reimagine Building Massive Impact (Sept 19): https://events.ringcentral.com/events/reimagine-buildings-massive-passive/registrationhttps://ukphc.org.uk/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive House Accelerator Podcast, Ilka Cassidy and Mary James are joined by sustainability experts Amy Cornelius, Paul Thompson, and Joe Messier as they delve into a groundbreaking retrofit project in Philadelphia. This six-part demonstration series, hosted by Green Building United, examines a project aligning with the new Phius REVIVE standard and the Living Building Challenge core principles. Listen as they discuss the integration of these standards, the challenges of retrofitting row homes, and the educational impact of their collaborative series. Discover key takeaways, innovative approaches to sustainability, and the surprising synergies between these certification programs. Tune in for an insightful exploration of how theory meets practice in sustainable building retrofits.
In this episode of the Passive House Podcast, co-hosts Jay Fox and Mary James speak with Gaelen McKee, Founder of Brooklyn Solar Works. They dive in to the company's origins, current projects, including work with co-ops and commercial buildings, and their plans for expanding into ground-mounted solar installations. Galen also touches on the impacts of tariffs, permits for residential batteries, and the future of whole-home electrification in New York City.https://brooklynsolarworks.com/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive House Podcast, Matthew Cutler Welsh interviews Jessica, a high-performance building consultant at Climate Shore in Adelaide. They discuss Jessica's transition from energy efficiency compliance to specializing in high-performance building with a focus on mitigating moisture risks. Jessica emphasizes the importance of proper construction practices and ventilation in preventing mold, touching on the challenges of getting builders and homeowners to adopt better practices. She highlights the relevance of Passive House standards and her involvement in promoting building science in Australia. https://www.linkedin.com/in/jessica-allen-esd/https://www.climasure.com.au/https://www.endurobuilders.com.au/https://building-sciology-poddie.podcastpage.io/?v=lfcmhttps://www.instagram.com/building.sciology/https://www.instagram.com/building.sciology/https://www.tiktok.com/@building.sociologyThank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
In this episode of the Passive Hosue Podcast, Zack Semke welcomes Michael Quast, the new CEO of Passive House Canada. Michael shares his diverse background in construction, business development, and media, emphasizing his passion for sustainable building. They discuss Michael's journey to Passive House Canada, his experience with straw bale construction, and his focus on fostering collaboration and breaking down silos within the sustainability sector. This episode highlights the importance of engaging both the building community and consumers to promote high-performance, energy-efficient buildings. https://www.passivehousecanada.com/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.https://passivehouseaccelerator.com/articles/passive-house-helping-shape-state-energy-codeshttps://passivehouseaccelerator.com/podcast/passive-house-podcast-ep-36-robyn-wark-bc-hydrohttps://passivehouseaccelerator.com/podcast/passive-house-podcast-encore-ep-robyn-wark-bc-hydro
In this episode of The Passive House Podcast, Mary James interviews Stephen O'Shea, head of Sustainable Construction at Carin Homes. Steven discusses the company's focus on large-scale residential projects, their commitment to Passive House standards, and the significant benefits for residents. He shares his journey from architecture to sustainable design, training strategies for implementing these standards, and the ecological measures taken on building sites. The episode also covers the need for public education on Passive House and previews an upcoming conference in collaboration with the Passive House Trust.https://www.cairnhomes.com/Thank you for listening to the Passive House Podcast! To learn more about Passive House and to stay abreast of our latest programming, visit passivehouseaccelerator.com. And please join us at one of our Passive House Accelerator LIVE! zoom gatherings on Wednesdays.
























fantastic podcast. Loved the hospital in Germany and the Brian Guinan ones especially...... a bit biased, as my partner is an architect who works for state government in Western Australia (worked on the Museum for 10 years, and currently working on a hospital), who is having her house built right now by Brian, which she designed. maybe you could ask her for an interview to get the view from the other side?