Building HVAC Science

Notable quote from the episode: Make it as simple as possible, but not simpler. In this episode, Eric Kaiser sits down with mechanical engineer Tony Amadio, the founder of True Loads, to talk about what actually makes residential load calculations succeed or fail in the real world. Tony shares how his work is split between builders, architects, project managers, and HVAC contractors, and why the biggest early battle was simply getting people to trust results that pointed to smaller equipment. He explains how he quickly learned from feedback loops in production housing, including what happens when people "over-vent" tiny spaces like closets and bathrooms, accidentally stealing airflow from bedrooms where it matters. Tony walks through his approach to receiving plans, emphasizing the importance of nailing down the building envelope inputs (windows, insulation, attic conditions) and getting key assumptions in writing. On renovations, he emphasizes that uncertainty is normal, so you lean on photos, field verification, and practical guidance to keep the model honest. They dig into infiltration and leakage, where Tony argues the models are still imperfect even with blower door data, and the real win is setting expectations: the HVAC design works under specific building conditions, and if the building does not match those conditions, performance issues are not automatically "bad calcs." The conversation closes with a discussion of equipment selection, humidity, and where the industry is headed. Tony makes a clear point: most standard residential systems do not directly control humidity, and the code focuses on temperature performance, not a promised indoor RH target. They also touch on ACCA Manual S updates, oversizing rules for staged equipment, and Tony's upcoming True Loads software, which uses the ASHRAE Heat Balance method to represent modern construction and time-lag effects better, while aiming to require fewer inputs than traditional Manual J workflows. TrueLoads website: https://1dtrueloads.com/ Tony on LinkedIn: https://www.linkedin.com/in/anthony-amadio-pe-7360952a/ This episode was recorded in December 2025.

QUOTES from the episode: "Most building failures aren't mysterious. They're just ignored fundamentals." "If you demand museum-level humidity, you're no longer building a house. You're building a museum." "Moisture meters don't solve problems. They show you patterns. The thinking solves the problem." In this episode of the Building HVAC Science Podcast, Eric Kaiser is joined by Kohta Ueno, principal and co-owner of Building Science Corporation, for a wide-ranging discussion on building failures, moisture, HVAC, and the practical realities of diagnosing real-world problems. Kohta shares his unconventional path into building science, from small remodeling jobs and a PBS NOVA episode to decades of forensic investigations alongside Joe Lstiburek, one of the field's most influential voices. The conversation quickly moves from origin stories into what really matters: how buildings fail, why those failures are often predictable, and how much cheaper it is to solve problems on paper than after construction. A major theme is moisture management, especially in high-performance and multifamily buildings. Kohta explains how seemingly small details, like window sill slope, back dams, airflow settings, and interior air seals, routinely separate durable buildings from expensive failures. He also highlights a growing perfect storm in modern construction: oversized HVAC equipment, high ventilation rates, poor commissioning, and limited dehumidification, particularly in smaller units. The result is mold, humidity complaints, and systems that technically run but fail to control moisture. The episode closes with a practical look at diagnostic tools and methods. Kohta emphasizes pattern recognition over single-point measurements, combining moisture meters, thermal imaging, pressure diagnostics, and blower door testing to understand how air, heat, and moisture actually move through buildings. He encourages listeners to use freely available Building Science Corporation research and Joe Lstiburek's Building Science Insights as foundational resources, reminding the audience that most building failures are not mysterious. They are repeatable, understandable, and avoidable if the fundamentals are respected. Kohta's LinkedIn: https://www.linkedin.com/in/kohta-ueno-472a4/ Links mentioned in the episode: Our Current HVAC Mess Experts discuss problems with residential HVAC systems as a first step toward defining solutions https://www.greenbuildingadvisor.com/article/our-current-hvac-mess Proposed Solutions for Residential HVAC Problems Experts suggest ways to improve the quality of residential heating, ventilating, and cooling equipment installations https://www.greenbuildingadvisor.com/article/proposed-solutions-for-the-residential-hvac-industry A presentation on my investigations of multifamily humidity problems: Multifamily Humidity Control Problems: Muggy Mayhem https://buildingscience.com/sites/default/files/presentation-docs/2021-05-06_nesea_be21_muggy_mayhem_ueno_for_pdf_0.pdf I have done a presentation on the diagnostic tools I use in my buildings forensic work; here's the slide deck: NESEA BE19 Tools of the Trade for Building Diagnostics March 14, 2019 https://www.buildingscience.com/sites/default/files/2019-03-14_nesea_be19_ueno_tools_trade_diagnostics_for_pdf.pdf 2019-03-14_NESEA_BE19_Ueno_Tools_Trade_Diagnostics.pdf And here's a YouTube video: Tools of the Trade for Building Diagnostics with Kohta Ueno https://www.youtube.com/watch?v=kCZIJFXDl9Q&t=2978s&ab_channel=TheBSandBeerShow The complete rundown of Joe Lstiburek's columns: https://buildingscience.com/document-search?search_title=&search=&field_doc_topics=All&field_doc_document_type=3&items_per_page=10 And some of the research reports we did under Building America: https://buildingscience.com/document-search?search_title=&search=&field_doc_topics=All&field_doc_document_type=8&items_per_page=10 This episode was recorded in January 2026.

Quotes from the episode: "Better isn't a goal, it's a direction." "HVAC can feel like a house of mirrors for homeowners, and the cure is transparency plus measured results." "We're not trying to find the perfect contractor. We're trying to find the contractor who keeps learning and won't get complacent." In this episode of the Building HVAC Science Podcast, Eric Kaiser flips the script and brings Bill Spohn on as a guest alongside Kevin Hart from Better HVAC and Darren Reuter and Huff Hoffmaster from Rewiring America. The group lays out a shared problem: homeowners face a significant information disadvantage when buying HVAC, often making a five-figure decision with no easy way to verify quality beyond marketing, promises, or price. That gap leads to mistrust, inconsistent outcomes, and too many "box swaps" that miss sizing, duct performance, commissioning, and homeowner education. Better HVAC exists to tip the odds back toward the homeowner by connecting people to contractors and individuals who commit to doing measured, commissioned work, and by aggregating trusted educational resources in one place. Rewiring America adds the consumer education and electrification planning layer, plus a push to scale adoption responsibly, with real contractor standards behind it. The partnership ties those strengths together: instead of building separate directories, they align on a shared pledge and a badging approach that helps homeowners and peers filter for contractors who are trained, insured, licensed, and willing to follow best practices, especially for heat pumps and whole-home electrification journeys that also include weatherization and energy auditing. Rewiring America's website: https://www.rewiringamerica.org/ BetterHVAC website:https://betterhvac.org/ BetterHVAC Pledge: https://betterhvac.org/pledge Huff's LinkedIn :https://www.linkedin.com/in/thomas-huff-hoffmaster-ii-766b3a36/ Kevin's LinkedIn:https://www.linkedin.com/in/kevinrhart/ Darren's LinkedIn:https://www.linkedin.com/in/darrenreuter98/ Bill's LinkedIn: https://www.linkedin.com/in/billspohn/ Corbett's list: https://homediagnosis.tv/hvac-installers This episode was recorded in January 2026

Quotes from the episode: "Good enough isn't a fixed point. It's a moving target shaped by goals, expectations, and consequences." "Perfection can push us forward, but it can also quietly pull us off track." "If I delivered what I promised, in the time promised, using the resources promised, that is good enough for me." "The real skill is knowing when extra effort adds value and when it just adds ego." In this solo monologue episode, Eric Kaiser explores a deceptively simple question: Can good enough be perfect? Drawing on years of experience in the trades, Eric reflects on how deeply perfectionism runs in technical work and how it can both elevate quality and quietly work against efficiency, clarity, and outcomes. Using a favorite quote from Dan Holohan, Eric reframes "good enough" not as mediocrity, but as work that meets the right goals, expectations, and time horizons. He walks through practical parameters that define when good enough truly is perfect, including the intended lifespan of the work, customer and regulatory expectations, available resources, and the real consequences of pushing beyond what the situation requires. Eric closes by offering a simple but powerful three-question test to evaluate our own work: Did I deliver what was promised? Was it done in the promised timeframe? And did I use the promised resources? If the answer is yes to all three, then maybe, just maybe, the work was perfectly good enough. This episode was recorded in December 2025.

Quotes from the Episode: "Innovation in HVAC isn't one big breakthrough. It's a series of quieter shifts that slowly change how we work." "The future of HVAC depends on the people who measure, verify, and continuously improve." "Collecting data is getting easier. Interpreting it well is where the real value lives." "True innovation isn't about chasing trends. It's about reducing uncertainty and delivering better outcomes." "Homes aren't a collection of parts. They're systems, and HVAC sits right in the middle of that system." In this solo episode, Bill Spohn reflects on how innovation in HVAC really happens, not through one flashy breakthrough, but through a series of quieter, incremental shifts that compound over time. Drawing from 250 episodes of conversations on the Building HVAC Science podcast, Bill reframes innovation as a mindset grounded in measurement, feedback, and systems thinking rather than just new equipment. Bill walks through key patterns he has observed across the industry, including the shift from equipment-focused thinking to system-level performance, the rise of connected and cloud-based field tools, and the growing role of software in interpreting data rather than just collecting it. He highlights how smart tools, real-time diagnostics, commissioning workflows, and platforms like MeasureQuick have changed troubleshooting, accountability, and profitability for contractors who embrace them. The episode also explores major themes shaping the future of HVAC: electrification and heat pumps, dual-fuel strategies, improved load calculations and design software, smarter controls and commissioning, and the rapid evolution of indoor air quality from a niche topic to a core expectation. Bill emphasizes the increasing integration of HVAC with building science, ventilation, moisture, and enclosure performance, and points to contractors who are thriving by treating homes as complete systems. He closes by reinforcing that true innovation is about reducing uncertainty, improving outcomes, and supporting continuous learning, all while encouraging listeners to explore BetterHVAC as a growing nonprofit resource for contractors and homeowners alike. This episode was recorded in December 2025.

Quotes from the Episode: "Good building systems don't start with equipment—they start with a plan and a thoughtful process." "Most comfort problems aren't equipment problems; they're building problems we haven't taken the time to understand." "If even one episode helps someone take the next step in their career, then it's all been worth it." Episode 250 of the Building HVAC Science Podcast flips the script. Instead of Bill Spohn and Eric Kaiser doing the interviewing, TruTech Tools' Senior Marketing Manager Ginny Hebert steps into the host seat to reflect on 250 episodes of conversations about comfort, buildings, and the people who work on them. What follows is an honest, thoughtful look back at what the show has uncovered—not just about HVAC systems, but about how people learn, think, and grow within the industry. Bill and Eric reflect on how their understanding of comfort has evolved, especially regarding concepts such as heat transfer, mean radiant temperature, air sealing, and treating the house as a system rather than a collection of parts. They discuss how many "equipment problems" are actually building or design problems, and why taking time to think—really think—about a problem is often the most valuable (and most overlooked) practice in the trade. The conversation highlights how technology, connected tools, and computing power have improved diagnostics, while also reinforcing that good outcomes still depend on mindset and process. The episode also looks forward. From normalizing system testing and indoor air quality assessments to improving how comfort is predicted and communicated, Bill and Eric share what they hope will become everyday practice over the next decade. Above all, this milestone episode is a thank-you to listeners, guests, and the broader HVAC and building science community—for staying curious, open-minded, and committed to doing better work for the people who live in the buildings we touch. Ginny's LinkedIn: https://www.linkedin.com/in/ginny-hebert/ Eric's LinkedIn: https://www.linkedin.com/in/eric-kaiser-323a1563/ Bill's LinkedIn: https://www.linkedin.com/in/billspohn/ This episode was recorded in December 2025.

Episode quotes: "Hydrogen sulfide doesn't announce itself. It can drift in, hit your mucus membranes, and start causing real harm before you know it's there." "You can't treat sensor response like magic—it's physics, chemistry, and smart filtering working together to tell you what's actually happening in the space." In this episode, Bill & Eric sit down with Dave Massner from Sensorcon, a long-time technical contributor in the world of portable gas detection, to dig into the realities behind CO, H₂S, and O₂ sensing in both HVAC and industrial environments. Bill recaps the origins of their relationship with Sensorcon, which sets the stage for Dave to explain why gas detection still matters and brings in real-world examples—from oil fields to everyday equipment rooms—to show how invisible hazards shape how techs should approach safety. The conversation explores lesser-understood threats like hydrogen sulfide (H₂S)—a gas that can travel with the wind in oil and gas regions and incapacitate workers before they realize it's there. We discuss the physiology, the chemistry, and the grim speed at which exposure can become deadly. From there, we shift to oxygen depletion, clarifying what "too low" actually means in field work and why measuring O₂ is just as important as detecting toxic gases. The episode also gets into the nuts and bolts of sensor behavior: signal-to-noise ratios, filtering, raw output, response time, and the clever algorithms that help instruments stabilize faster without sacrificing accuracy. Toward the end, we highlight Sensorcon's ongoing efforts in training, education, and transparency, pointing listeners to the company's technical blog posts, videos, and calibration resources. We also make the case for low-level CO alarms and why TruTech Tools has championed them for over a decade. As we wrap up, we leave listeners with a simple takeaway: understand your sensors, understand your risks, and choose equipment that treats safety as something more than a checkbox. Dave's LinkedIn: https://www.linkedin.com/in/david-massner-30291189/ Sensorcon at TTT: https://trutechtools.com/sensorcon-solutions.html Sensorcon blog posts:https://sensorcon-sensing-products-by-molex.myshopify.com/blogs/news/ Sensorcon videos: https://sensorcon-sensing-products-by-molex.myshopify.com/pages/inspector-videos Low-level CO alarms at TruTech Tools: https://trutechtools.com/installedco This episode was recorded in December 2025.

"Inspect your marketing the way you'd inspect a home—run diagnostics, don't guess." – Aaron Husak "Attitude is way more important than aptitude. One bad apple really can infect the whole company." – Aaron Husak In this episode of the Building HVAC Science podcast, Eric and Bill sit down with long-time friend and contractor-turned-marketing pro, Aaron Husak. Aaron traces his winding path from solar in the mid-2000s to building performance and BPI training, and then to founding Balanced Comfort in Fresno, CA. What started as a small HERS and energy-audit firm bootstrapped its way into insulation, HVAC, and weatherization, eventually landing on the Inc. 5000 list four times and scaling from $1.3M to over $12M in just a few years. Along the way, Aaron learned the complex realities of rapid growth: hiring quickly, depending on rebate programs, uncovering serious gaps in back-office accounting and HR, and navigating California's legal landscape. Things got especially rough when PG&E abruptly pulled a weatherization program that made up half of their revenue, right as Aaron was also dealing with the personal loss of both his parents. A rescue buyer ultimately acquired the company in early 2025, giving Aaron a hard-earned exit. From that experience, Aaron pulls out lessons for contractors who want to grow without blowing themselves up. He emphasizes perseverance, but also warns that good field tech screening doesn't automatically translate into good screening for accountants, HR, and support staff. He talks about the cost of keeping the wrong people too long, the importance of outside eyes on your books and compliance, and why attitude beats aptitude when building a healthy culture. He also calls out how easy it is to underestimate the impact of programs, receivables, and legal exposure—especially in states where "it doesn't matter if you're right, you still have to pay the attorney." Today, Aaron has pivoted into his next chapter with Sequoia GEO, a marketing firm focused on contractors and local service businesses, with a special emphasis on AI and "GEO" (Generative Engine Optimization). He explains why your Google Business Profile is the low-hanging fruit almost everyone neglects, how AI tools and devices like Plaud can turn field conversations into high-value website content, and why AI "likes structure" (bullets, lists, and real stories). The episode closes with practical advice: inspect your marketing like you would inspect a home, use affordable diagnostic tools to see what's really happening online, stay transparent with customers about recording and privacy, and treat expensive mistakes as lessons that tighten your processes for the future. Aaron's LinkedIn:https://www.linkedin.com/in/ahusak Aaron's Company: www.SequioaGEO.com Aaron's Blog: https://www.sequoiageo.com/blog/categories/google-business-profile This episode was recorded in November 2025.

"Get mad at the problem, not the person. When people feel safe, they'll actually bring you the real issues." - Bill Spohn "We're woven into the fabric of this industry. The industry made me—so in a way, it owns me." - Bill Spohn "What we have to learn to do, we learn by doing." - Aristotle In this episode, Eric turns the mic around and interviews his co-host, Bill Spohn, about the evolution of TruTech Tools, his leadership philosophy, and why he's shifting from "Chief Executive Officer" to "Chief Education Officer." Bill traces the roots of TruTech back to late 2006, when a suggestion at a Testo Christmas party planted the seed for an online test-instrument business that launched in April 2007. He talks about how TruTech has become "woven into the fabric of the industry," helping connect HVAC and building performance pros while focusing on specialty tools, education, and best practices. A big chunk of the conversation is about people: attracting and retaining the right employees, and running the business through the lens of core values. Bill and Eric walk through TruTech's four core values—Do the Right Thing, Be a Team Player, Get It Done, and Be Attentive—and how they were distilled from nearly 80 traits the leadership team admired in their co-workers. Bill explains how these values show up in hiring (situational questions), in problem-solving (getting mad at the problem, not the person, and using the "five whys"), and in daily decisions about how to treat customers and each other. Bill also opens up about his intentional five-year transition plan out of day-to-day leadership and into a more advisory and educational role, including transferring ownership and the President role to his son. He shares why he didn't want to be the owner who leaves on a stretcher—or the one who keeps wandering back in and undermining the next generation. Instead, he's leaning into training the team, mentoring startups, and building out the Better HVAC directory as a free resource for contractors and consumers. Along the way, he and Eric talk about the "comfort industry" as a whole, the blending of HVAC and building performance, the importance of passing down institutional knowledge, and even Bill's side quest to learn rock guitar and someday join the Building Science Boogie Band. This episode was recorded in November 2025.

Episode quotes: "Below about 0.4 microns, many low-cost PM sensors are basically guessing—right where wildfire smoke and aerosols live." — Sissi Liu "Electrostatic filters can look great at first—and then fall off a cliff in smoke. Pressure drop won't warn you." — Sissi Liu "Science is a way of thinking much more than it is a body of knowledge." — Carl Sagan Eric digs into the "fresh air" myth with Sissi Liu, CEO/co-founder of Metalmark Innovations and active ASHRAE committee member. Sissi explains why "outdoor = fresh" is context-dependent—urban pollution, agricultural activity, and especially wildfire smoke can make outdoor air worse than indoor air. Because air quality is dynamic, she pushes for comparing indoor and outdoor conditions in real time and ventilating intelligently, with attention to the energy cost of conditioning outside air. They then get nerdy on sensors and filters. Many low-cost PM2.5 laser-scattering sensors struggle below ~0.4 µm and can misread certain particle types (e.g., dark/black carbon), which matters because smoke and pathogen-carrying aerosols often live in the ~0.1–0.3 µm range. On filtration, Sissi contrasts mechanical vs. electrostatically charged media: electrostatic filters start efficiently with low pressure drop but can lose effectiveness within hours in smoke events. In contrast, mechanical media hold up better (though at higher pressure). She highlights ASHRAE 52.2 Appendix J (loaded efficiency) and argues that standards—along with reporting practices—must evolve for wildfire realities. Key takeaways "Fresh air" is conditional: check outdoor AQ (and indoor) before cranking up ventilation. IAQ is dynamic; test and compare locally rather than assuming static conditions. Consumer PM sensors can under-count the tiniest and darkest particles; treat data with caveats. Wildfire smoke clusters in the most-penetrating particle size (~0.1–0.3 µm) for many filters. Electrostatic filters may degrade fast in smoke; pressure drop alone won't reveal failure. ASHRAE standards (e.g., 52.2 Appendix J, SGPC-44) are evolving—industry needs to catch up. Sissi's LinkedIn: https://www.linkedin.com/in/liusissi/ Metalmark website: https://metalmark.xyz/ This episode was recorded in October 2025.