EP239 Psychrometrics, Mobile Apps, and the Future of HVAC with Carmel Software (September 2025)
Release Date: 10/10/2025
Building HVAC Science
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:...
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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...
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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,...
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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...
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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...
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“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...
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“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...
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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...
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Eric Kaiser sits down with Haley Harlow and Al Mitchell from PHIUS (Passive House Institute US) to explore Revive 2024, a groundbreaking new retrofit standard focused on thermal resilience and healthier, safer existing buildings. Haley shares her path from Pennsylvania College of Technology to her current role managing building certifications at PHIUS. At the same time, Al recounts his journey from aspiring car engineer to building scientist, drawn to the elegant complexity of whole-building systems. Together, they unpack how Revive differs from traditional PHIUS new-construction standards....
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Quotes by Brantley: “Most moisture problems are a three-way dance—envelope, mechanicals, and the occupants.” “Skim the light, don’t blast it. The right flashlight technique makes the invisible visible.” “If you only understand one piece of the system, you’re solving 1/3 of the problem.” Indoor environmental specialist Brantley May joins the show to unpack how he investigates moisture, mold, and air-quality problems through building forensics. Starting as a mold remediator in his family business, Brantley shifted to assessment work and now runs national...
info_outlineStephen Roth—founder of Carmel Software and current owner of Hands Down Software—joins Bill and Eric to trace a multigenerational journey from a 1920s Ohio roofing firm to modern HVAC software that powers everyday field work. Stephen shares how family roots in commercial roofing and energy management shaped his path as a mechanical engineer and coder, eventually leading to Autodesk acquiring his early load-calc assets and, later, to relaunching Carmel with one of the industry’s first mobile HVAC app suites.
Today CarmelSoft offers field-friendly tools from PT charts and duct/pipe sizers to an ACCA-approved Manual J (HVAC ResLoad J) iPad app. Stephen also discusses custom projects for Carrier, Mitsubishi, SMACNA, and ASHRAE (including Building EQ), plus the acquisition and revitalization of the ubiquitous Hands Down psychrometric chart software. Looking ahead, he sees AI accelerating data entry, plotting psychrometric processes by prompt, and facilitating web-based collaboration—always in service of the core mission: helping technicians and engineers accurately size systems and design energy-efficient buildings.
Notable quotes:
“Our mission is to help technicians and engineers easily and accurately design energy-efficient buildings.” — Stephen Roth
“The city of Phoenix wouldn’t exist without our industry.” — Stephen Roth
Stephen’s LinkedIn: https://www.linkedin.com/in/stephenbroth/
Camelsoft website: https://carmelsoft.com/
HandsDown website: https://www.handsdownsoftware.com/
Upcoming webinars: https://carmelsoft.com/Carmel-Software-Mobile-Training-Webinars
Past recorded webinars: https://carmelsoft.com/Carmel-Software-Video-List
Contact form: https://carmelsoft.com/Carmel_Software_ContactUs.aspx
This episode was recorded in September 2025.