The Building Science Podcast

Positive Energy

The Building Science Podcast is a show hosted by MEP engineering firm Positive Energy principal Kristof Irwin. The show covers everything from the basics of building science to adjacent scientific disciplines to more fully understand how the built environment shapes our lives as human beings on planet earth.

  1. 5d ago

    Thermal Truths

    Homes and buildings are more than just boxes filled with air at the right temperature; they are complex thermodynamic environments deeply coupled with our bodies, minds, and emotions. We are lucky to be alive during this time of change in how the AEC understands what creates and delivers thermal comfort. Beyond the static “thermal blandness” model of the 1970s, we now realize that transient thermal dynamics can deliver both comfort and “thermal delight”. Join us for a lively and thought-provoking conversation with Dr. Dorit Aviv, an architect and engineer working at U Penn.  Dorit, a licensed architect and building scientist who now leads cutting-edge research on the design of thermal environments both indoors and out. Her work bridges the gap between the wisdom of ancient cooling and heating systems and high-tech 'future-casting' with spectrally selective materials to unlock membrane-assisted radiant cooling in humid environments. Along the way, we’ll dive into the mechanisms of thermal comfort, the human experience of thermal environments and recognize that society is due for an upgrade in the way we think about delivering comfort.  We conclude by pointing out the sobering reality that, thermal stress is increasingly becoming a health hazard for society. Just as society did with sewage and sanitation codes, we now face the need for a holistic approach to heat stress. Fortunately researchers like Dorit are setting us up to be able to prevent loss of life to thermal stress. Now is the time for all of us in the AEC to recognize the need for the 'Architecture of Public Health’ when it comes to our thermal environment. Dorit Aviv Dorit Aviv, PhD, AIA, is an Associate Professor of Architecture at the Weitzman School of Design, specializing in environmental performance. She is also a faculty member of the Material Science and Engineering (MSE) graduate group in the School of Engineering and Applied Sciences. She is the director of the Thermal Architecture Lab, a cross-disciplinary laboratory at the intersection of thermodynamics, architecture and material science. Her work examines paths to decarbonization of the built environment through design and policy. Specifically, she looks at the potential synergies between renewable environmental forces and architectural materials and forms, and their impact on buildings' energy performance, air quality, and human health. Aviv's work has been supported by federal grants from the the National Science foundation, the National Institute of Health, U.S. Department of Energy, the Environmental Protection Agency, and the National Park Service, as well as by industry collaborations with Microsoft, Ripple, and Armstrong World Industries. In 2021 she was awarded a Holcim Award for Sustainable Design and Construction for a prototype of passive cooling in desert climate. In 2024 she received a Ramboll Foundation grant to investigate architectural applications of membrane-assisted radiant cooling. The resulting pilot heat shelter - KlimaKover, received the 2026 AIA-NYS project award in the infrastructure category. Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

  2. Jul 22

    The Progress Paradox: How Codes Create Carbon

    An interview with Kelly Alvarez Doran Why do our building codes encourage carbon pollution? How have we landed in a "progress paradox," where older buildings often outperform new ones in both operational and embodied energy? In this episode, we sit down with Kelly Alvarez Doran, co-founder of Ha/f Climate Design, to unpack the hidden impacts of the built environment—a sector responsible for nearly 40% of global emissions. The good news is that architects and planners can use their agency to stop these "right now" pollutants. Meaningful decarbonization doesn’t have to cost a premium: Kelly shares how simple material swaps recently slashed a UK project's carbon by 26% (800 tonnes) with zero impact on the budget or schedule. Kelly Alvarez Doran Kelly is a father, architect and educator. His holistic approach to the design of the built environment has been shaped by his experiences working across the world - first in the resource development sector, and later as MASS Design Group’s East African Director where he led the design and implementation of several of MASS’s projects, notably the Rwanda Institute for Conservation Agriculture–winner of several international awards for sustainable design and construction. Working in these contexts brought about a profound sense of the scales of social and environmental impacts inherent to the built environment.  Kelly is an Adjunct Professor at the University of Toronto, a Senior Fellow of Architecture 2030, a founding member of the Bio-based Materials Collective, a winner of the Canada Council’s Prix de Rome for Emerging Practitioners, and a member of the RAIC’s Committee on Regenerative Environments. Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

  3. Jun 18

    Demystifying Decarbonization: Data Driven Design

    In this episode, Kristof sits down with sustainability expert Josh Jacobs to demystify the ins and outs of Life Cycle Assessments (LCAs), Environmental Product Declarations (EPDs), Product Category Rules (PCRs) and ISO Standards that are causing a decarbonization to happen around the world. Translating the complex data of an LCA into a standardized format, EPDs function as 'nutrition labels' for building materials, helping designers and specifiers count the 'carbon calories' of everything from steel girders to heat pumps. Josh and Kristof explore the critical shift from focusing exclusively upon operational carbon to including embodied carbon in the carbon reduction conversation, break down the cradle-to-grave phases of building materials, and offer actionable insights on using better data to make truly sustainable design decisions. Apologies that Kristof’s mic was clipping.  Josh Jacobs Josh has helped numerous AHJs develop and implement sustainable purchasing policies and requirements, including but not limited to: the US General Service Administration, the US Military through the UFGS, the State of California, the city of New York, the Building Construction Authority of Singapore, and numerous universities and private businesses. Josh has also helped develop influential materials, human health, product emissions, and indoor air quality criteria in numerous global codes and rating systems, including but not limited to LEED v4 and v4.1, Fitwel, Green Globes, CALGreen, IgCC, ASHRAE 189.1, and BREEAM. He also works with organizations investor relations and sustainability teams to understand ESG financial reporting tools such as SASB, GRI, and TCF along with looking at their carbon footprint. Links from the Episode Organizations Mentioned: MEP2040: An organization and steering committee focused on decarbonizing mechanical, electrical, and plumbing systems. WAP Sustainability Consulting: A large life cycle assessment organization that helps manufacturers create EPDs. SLR: A global environmental and advisory firm that owns WAP. USGBC: The U.S. Green Building Council, associated with the LEED rating system. ASHRAE: The American Society of Heating, Refrigerating and Air-Conditioning Engineers. ISO: The International Organization for Standardization. NSF: An organization with an EPD program (distinct from the National Science Foundation - originally focused on water certification). UL: Underwriters Laboratories, an early EPD program operator in North America. ICC-ES: The International Code Council Evaluation Service, an EPD program operator. ASTM: An organization that features an EPD program. ANSI: The American National Standards Institute. CIBSE: The Chartered Institution of Building Services Engineers based in the UK. NAHB: The National Association of Home Builders. Standards and Financial Tools ISO 14040 / ISO 14044: International standards that provide the framework and guidelines for conducting LCAs. ISO 14025: The standard that governs how program operators run EPD programs and dictates what should be included in an EPD. ISO 21930: The overarching Product Category Rule (PCR) for building materials typically used in the Americas. EN 15804: The European equivalent to ISO 21930. ISO 20400: The standard for Sustainable Procurement. ASHRAE 189.1: A standard for the design of high-performance green buildings. IgCC: The International Green Construction Code. CIBSE TM65 / North American CIBSE/ASHRAE TM65: A standard that approximates an LCA to provide directionally accurate information when a full EPD is not available. SASB, GRI, TCFD: Sustainable financial reporting tools used by organizations and investor relations teams. Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

  4. Apr 25

    Perspectives on Hydronics in the Real World

    An interview with Robert Bean and Lance MacNevin In this episode we unpack the rapidly transforming world of hydronic heating and cooling. We are joined by two seasoned veterans of the industry, Robert Bean and Lance MacNevin. With many decades of real-world experience and hard-earned perspective between them, they offer a thoughtful and engaging look into why hydronics is at the forefront of modern, highly efficient building practices. Robert is (attempting to be) a retired engineering technology professional and ASHRAE Fellow, while Lance brings his extensive background serving as the Director of Engineering at the Plastics Pipe Institute.  This episode is packed with sound-bite worthy moments as our guests cut through the noise to discuss the realities of hydronic-based thermal comfort. Whether you are a homeowner, architect, or builder, you will find their independent, expert perspectives well worth listening to and holding on to. This is definitely an episode you will want to bookmark and share with anyone interested in the future of the HVAC industry! Robert Bean Robert Bean is a retired engineering technology professional who specialized in the design of indoor environments and high-performance building systems. Mr. Bean is an ASHRAE Fellow and ASHRAE Distinguished Lecturer, recipient of the Lou Flagg Award, Distinguished Service Award, and instructor for the ASHRAE Learning Institute. He has authored many papers, articles, and course curricula, and has served on numerous technical committees related to indoor environmental quality, building, and energy systems. Lance MacNevin Lance MacNevin, P.Eng. is the senior director of engineering for the Plastics Pipe Institute’s Building & Construction Division, with expertise on pressure pipes such as CPVC, HDPE, PEX, PE-RT, and PP. Lance has been in the plastic pipe industry since 1993, working as an R&D engineer, codes and standards specialist, and trainer for a major piping manufacturer for over twenty years before joining PPI in 2015. In this role, he focuses on plumbing and mechanical systems, coordinating research, education, and advocacy activities. He is an active member of ASHRAE, ASPE, ASTM, AWWA, CSA, IAPMO, ICC, IGSHPA, NSF, and RPA. Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

  5. Apr 8

    (Un)Healthy Homes

    An interview with Dr. Eva King Our homes are indoor environments of our own making. These environments exist to make our lives better but often unintentionally expose us to contaminants—chemical and microbial—that harm our health and wellbeing. For genetically susceptible individuals, these routine exposures can trigger a breakdown in the body's natural tolerance, leading to chronic inflammatory and neurological symptoms such as CIRS, TILT, and PANS/PANDAS. In a sadly apt metaphor, we are the canaries and our home is the coal mine.  Today, we are joined by a frontline expert in this field, Dr. Eva King. Eva holds a Masters in Biochemistry and a Doctorate in Immunology/Epidemiology from the University of Oxford. She has dedicated more than two decades investigating the intersection of indoor environments and human health. Her focus is helping clients with underlying medical conditions identify and address building-related issues that contribute to their health problems. This interview is fuel for the journey to flip our indoor environments from being a major contributor to chronic disease to becoming a primary solution. This is a central and sobering topic for all of us with agency in the AEC. Please listen and share. Eva King Dr. Eva King, principal and founder of AURA EnviroScience, has been involved in investigations and research into indoor environments and health, allergens, asthma and immunology for about 20 years. Her work has been published in many peer-reviewed scientific publications, and she regularly presents at conferences and workshops. Her focus is helping clients with underlying medical conditions identify building-related problems that contribute to their health issues, often by direct physician referral. Dr. King received her Master in Biochemistry in her native Germany, and her Doctorate in Immunology/Epidemiology from the University of Oxford, UK, and is a Council-certified Indoor Environmental Consultant (CIEC, ACAC #180311). She is a member of ASHRAE, the American Industrial Hygiene Association (AIHA), American Conference of Governmental Industrial Hygienists (ACGIH), and the International Society of Indoor Air Quality and Climate (ISIAQ), and previously served on the Board of Directors and as Technical Conference Chair of the Indoor Air Quality Association. Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

  6. Feb 12

    Our Hidden Roommates

    An interview with Dr. Sarah Haines The Indoor Microbiome is the complex, invisible world of trillions of microorganisms living within indoor environments. Its residents include bacteria, archaea, fungi and viruses. We live immersed in this ecological niche, for good or ill. A typical home can host between 500 and 1000 different species of bacteria in household dust alone, and thousands of species of mold, yeast and viruses are in the air and on the surfaces around us. Together they serve as the primary ecological interface through which buildings influence human biology. In this light, we are beginning to view indoor environments not merely as passive shelters, but as active, highly complex indoor ecosystems that actively influence our immune and endocrine function, and long-term wellbeing. Today, we are joined by Dr. Sarah Haines, Assistant Professor at the University of Toronto and Principal Investigator of the IMEE Lab, to explore the foundational framework behind this shift. We will discuss the emerging perspective of "biologically informed architectural design" and the fact that architects and interior designers don’t just curate materials, they curate our basic microbial exposures and therefore our health and wellbeing. Sarah Haines Dr. Sarah R. Haines is an interdisciplinary researcher and educator working at the intersection of building science, environmental engineering, and microbiology to investigate how indoor environments shape human health. Assistant Professor in the Department of Civil and Mineral Engineering at the University of Toronto, the Principal Investigator of the Indoor Microbiology and Environmental Exposures (IMEE) Lab and member of the Hub for Advancing Buildings. She holds a BS in Environmental Engineering and an MS and PhD in Environmental Science from The Ohio State University. Her research focuses on maintaining healthy and sustainable indoor environments through detection and characterization of abiotic and biotic indoor exposures using a variety of techniques​. She integrates community-based participatory research, advanced molecular techniques (e.g., high-throughput sequencing, digital PCR, metatranscriptomics) and filter forensics to examine microbial dynamics and contaminant exposures indoors. Her work includes studies of moisture-driven mold growth in building materials, microbial volatile organic compound emissions, and the use of filter dust to estimate airborne concentrations of contaminants and pathogens, including SARS-CoV-2. Through this research, she develops practical, evidence-based strategies to reduce harmful indoor exposures, particularly in the context of climate change and housing inequities. Prof. Haines is a member of the American Association for Aerosol Research (AAAR) and the International Society of Indoor Air Quality and Climate (ISIAQ), as well as the Institute of Health Emergencies and Pandemics (IHEP) contributing to interdisciplinary efforts that connect indoor air quality, building performance and health. She was the 2024 recipient of the University of Toronto Faculty of Applied Science & Engineering Early Career Teaching Award, recognized for excellence in teaching and mentorship. Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

  7. Jan 27

    Hydronics: The OG HVAC - Part 2

    An interview with Benjamin Jewell. This is Part 2 of our latest series to familiarize our industry with the world of hydronics systems and air-to-water heat pumps. In Part 2 we’re rejoining the conversation to look at controls - the "central nervous systems" of these hydronics. We’re moving beyond old-school mechanical switches to a new class of microprocessor based systems that prioritize "outcomes"—like thermal comfort and air quality—rather than just reacting to thermostat calls. This shift is about adding intelligence that anticipates comfort needs and makes the system more stable and predictable for both the installer and the homeowner . We also dive into the high-stakes world of the global refrigerant transition and how hydronic systems allow a home to become "refrigerant agnostic" and truly future-proofed . We unpack the potential of natural refrigerants like R-290 (propane) and discuss why builders and developers are the key stakeholders in the transition of this product class from high-end homes to the baseline approach for every home that’s built. We wrap up by looking at how simplified "kit" solutions are finally removing the traditional barriers of labor and complexity to make hydronics accessible for the mainstream market. Benjamin Jewell Director of Carrier Hydronics NA (Climate Solutions Americas) As the Director of Carrier Hydronics North America within the Climate Solutions Americas division, Ben Jewell leads a multifaceted organization comprising Product, Engineering, and Technical Services teams. His leadership spans the entire product lifecycle, from initial development and long-term strategic planning to the integration of digital tools and portfolio management. Ben is dedicated to stewarding residential and light commercial hydronic products across a diverse range of differentiated brands, driving his team to win every day through innovation and operational excellence. Before joining Carrier, Ben spent over four years as a Senior Product Line Manager for Viessmann Climate Solutions. During this time, he managed extensive portfolios in the residential and light commercial sectors, specializing in heat pumps, chillers, domestic water heating, ventilation, indoor air quality, and air distribution. This deep technical foundation informs his current approach to solving complex climate challenges and delivering high-performance solutions to the market. Beyond his executive responsibilities, Ben is a passionate advocate for mentorship and industry education. He frequently invests his time in sharing resources and supporting those looking to solve tough problems that make the world a better place, including contributing to industry knowledge through podcasting. Driven by the goal of being a proactive force in the world, Ben aims to look back on his career with the confidence that he "happened to the world" by making a tangible, positive impact on the industry and the environment. On a personal level, Ben is a devoted husband and a father to three daughters, a dog owner, and a "food rescue" enthusiast. While he describes himself as an average fly fisherman and perhaps a naturalist in another life, he spends the bulk of his days enjoying what he considers his dream career. His journey has taken him from Iowa City to Milford, Connecticut, and Stony Brook, New York, eventually leading him to his forever home base in Fort Collins, Colorado. Despite his many moves, he remains a loyal Iowa Hawkeye at heart—Go Hawks! Team Hosted by Kristof Irwin Edited by Nico Mignardi Produced by M. Walker

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177 Ratings

About

The Building Science Podcast is a show hosted by MEP engineering firm Positive Energy principal Kristof Irwin. The show covers everything from the basics of building science to adjacent scientific disciplines to more fully understand how the built environment shapes our lives as human beings on planet earth.

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