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.

• "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.

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. Instead of focusing on heating and cooling load targets, Revive emphasizes thermal resilience—a building's ability to remain habitable for up to a week during power outages or extreme weather. They also discuss ReviveCalc, PHIUS's new software tool for analyzing retrofit scenarios, allowing designers to test various upgrade packages, balance cost and performance, and phase improvements over time. The tool incorporates lifecycle cost analysis, dynamic energy modeling, and resilience metrics, making advanced design decisions more accessible to real-world projects.

Both guests share their excitement about addressing the massive stock of underperforming existing buildings. Haley connects it to her own experience growing up in energy-intensive apartments, while Al reflects on how to use today's computing power better to design resilient, efficient homes. They close with a shared message: retrofitting our current buildings is not only possible, it's essential for the future of sustainability, comfort, and community resilience.

• PHIUS Revive 2024 focuses on retrofits, bringing resilience and energy equity to the existing building stock.
  
  

• Thermal resilience replaces traditional load metrics, ensuring buildings remain habitable during grid or system failures.
  
  

• ReviveCalc helps users model envelope and mechanical upgrades, estimate lifecycle costs, and optimize phase-by-phase improvements.
  
  

• The program aligns with ASHRAE Guideline 0.2 for commissioning and integrates EPA's Energy Savings Plus Health framework.
  
  

• Air sealing remains the top "bang for the buck" retrofit measure for both comfort and energy savings.
  
  

• CPHC certification (Certified PHIUS Consultant) is open to anyone—no degree required.
  
  

• The Revive approach balances performance, cost, and practicality for real-world projects.

Haley's LinkedIn: https://www.linkedin.com/in/haley-harlow-3965b41b5

Al's LinkedIn: https://www.linkedin.com/in/al-mitchell-bb74827b/

Info on Phius Revive 2024: https://www.phius.org/phius-revive-2024

This episode was recorded in October 2025.

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 investigations that pinpoint root causes—from envelope leaks and interstitial space connections to mechanical design and operation issues. He explains the value of "flashlight technique" (skimming light across surfaces to reveal early hyaline mold) and why good eyes, a light, and critical thinking are still the most important tools in the bag.

Brantley walks through his toolkit—manometers, blower doors, pressure pans, thermal imagers, moisture meters, anemometers/flow hoods, data loggers, and even a backup sling psychrometer—plus his new favorite screening instrument, the InstaScope, which provides real-time readings on particulates, mold/pollen, bacteria/virus, VOCs, and CO₂. Investigations culminate in a report and protocols for the envelope, mechanicals, and remediation, often requiring tight coordination across multiple trades. He stresses pre-drywall inspections, "red-pen" continuous air/thermal barrier checks, and long-term monitoring to verify theories—especially on complex modern designs where vented attics and interstitial spaces end up unintentionally connected.

A major theme: cross-disciplinary literacy. Most condensation/humidity problems stem from three interacting factors—envelope failure, mechanical failure, and occupant behavior—so HVAC pros must understand building science, and envelope pros must understand HVAC. Brantley shares how training (BPI, IICRC), mentorship, microscopy work (McCrone/Ochsner), and relentless curiosity shaped his practice. Watch for him at industry events (HVACR School Symposium, Build Show)—maybe even submitting a short BryX talk next time.

Brantley's LinkedIn: https://www.linkedin.com/in/brantley-may-b3988283/

His company: EnviroHealth.co

His Instagram: https://www.instagram.com/brantley.iaq/

McRone Institute: https://mccroneinstitute.org/

Instascope: https://www.instascopeair.com/

Institute of Inspection Cleaning and Restoration Certification: https://iicrc.org/

Building Performance Institute: https://www.bpi.org/

Building Science Summer Camp:

https://buildingscience.com/events/twenty-fifth-annual-westford-symposium-building-science

National Home Performance Conference: https://building-performance.org/events/national/

This episode was recorded in October 2025.

Episode Quotes from Kevin Weaver:

"If we can quantify delivered capacity on the air side, we can work our way back to what's happening on the refrigerant side."

"We don't have to diagnose everything remotely — we have to be great at saying, 'there's a problem,' and prioritizing action."

"Even the best design can be wrecked at installation. Execution matters."

Chief Engineering Officer Kevin Weaver joins Eric and Bill to go beyond "remote monitoring" and explain how SmartAC is really a loyalty and trade-intelligence platform for residential HVAC. With three simple wireless sensors — a supply-air "comfort" sensor (temp/RH), a filter sensor (temp/static pressure), and a water sensor — plus a cloud-connected hub, SmartAC tracks delivered capacity and trends changes over time. That minimum viable data set lets contractors catch problems early, prioritize the right calls, and give homeowners peace of mind without needing full remote gauges.

Kevin walks through the contractor toolset, which includes a white-labeled homeowner app, a Pro app for technicians, and a partner dashboard that also integrates with Field Service Management. (FSM) systems like ServiceTitan. The result is fewer emergency visits, healthier memberships, and durable customer relationships (i.e., less ad spend, more lifetime value). He previews Gen-2 hardware (more sensing in more places, stronger radios), battery options (18 months on AA lithiums or 5–8 years with a long-life pack), and notes that SmartAC is approaching 100k homes sold — building one of the most extensive residential HVAC data sets for richer insights across brands, geographies, and system types.

We conclude with wisdom from Kevin's Texas A&M research: even great designs can fail due to poor execution. Right-size returns, stretch flex, use collars and mastic, and keep static in check. SmartAC's data helps expose oversizing, blower mis-settings, and undersized returns in days, transforming maintenance plans into smart maintenance and turning "transactional" customers into lifelong customers.

Kevin's LinkedIn: https://www.linkedin.com/in/kevin-weaver/

SmartAC: www.smartac.com

Earlier episode with founder Josh Teekell (Ep. 136):

https://www.buildinghvacscience.com/ep136-utilizing-smart-maintenance-plans-benefits-your-customers-and-your-business-with-josh-teekell/

This episode was recorded in October 2025.

QUOTES from the Episode

"Instead of landlines everywhere, give every heat pump a cell phone and let it call home."

"We're seeing close to 40% of heat pumps undercharged or leaking—no wonder callbacks are high."

"What gets measured gets managed." — often attributed to Peter Drucker (fitting this data-driven shift)

Brendan Hermalyn (CEO/founder, Thalo Labs) traces a zig-zag path from NASA and defense to self-driving cars—then into HVAC. His through-line: high-reliability sensing and prognostics. Thalo's product aims to "give every heat pump a cell phone," using a small, non-invasive module that snaps inside VRFs/splits (and eventually larger plants), measures power and line temps, backhauls via cellular, and flags undercharge/leaks and power-quality issues before they become emergency calls. It's equipment management, not a full BMS—lightweight to install, built for techs, and friendly to API integrations, texts, and weekly roll-ups.

Brendan argues the market is ready: most commercial buildings still lack BMS, Wi-Fi is fragile for critical telemetry, and the economics of sensors/cloud have flipped. Thalo avoids tapping the refrigerant loop, prioritizes fast installs (often 10–30 minutes), QR/location tagging, and even a "buzz this unit" feature to find the right rooftop box. Early field data is sobering—he's seeing ~40% of heat pumps undercharged and/or leaking—driving callbacks, compressor failures, and energy waste. The pitch to contractors: turn break-fix chaos into planned maintenance, white-label the savings report, and train new techs faster with data-driven cues. Oh, and the name? "Thalo" like the deep sky blue—an homage to adding tech to make the picture clearer.

Brendan's LinkedIn: https://www.linkedin.com/in/brendan-hermalyn/

Thalo Labs: https://thalolabs.com/

This episode was recorded in October 2025.

Totex co-founder Berlin Raj joins Eric and “Overkill Bill” to unpack a single-box, hydronic monoblock system that combines space conditioning, domestic hot water, pool heating, thermal + lithium storage, EV charging integration, and backup power. Born from Berlin’s lifelong tinkering (and many shocks), the idea: stop wasting condenser heat—capture it for hot water while cooling.

The system keeps all refrigerant sealed in the outdoor unit and runs PEX supply/return to indoor air handlers (ducted or ductless), avoiding field flares and refrigerant line runs. Install looks familiar—set the pad, pipe PEX, fill a glycol loop, wire power/control—yet it adds clever tricks: load matching from ~1.5–6 tons, dynamic load limiting for small panels (even ~20–30A circuits), modular thermal storage (~100 kWh cooling / ~55 kWh heating), a ~10.5 kWh lithium pack, and app/10" touchscreen controls over Modbus with hooks for BMS and home automation. In cooling-plus-hot-water mode, field tests show very high effective COP (Berlin cites “9+”) because the unit harvests both sides of the cycle.

Engineered for residential and light commercial (think houses, small offices, QSRs), the unit can supply hot water up to ~165°F, support radiant/underfloor at lower temps, operate down to about -7.6°F, and be manifolded for capacity and redundancy. Texas is the target U.S. beachhead (long cooling seasons = months of “free” hot water), with pilots in Australia and U.S. pilots planned; broader availability is aimed for mid to late next year. Berlin’s closing note? “People, people, people”—comfort and outcomes start with humans.

Notable Quotes:

“Why dump condenser heat when you can use it? Cool the house and make hot water at the same time.” — Berlin Raj

“Dynamic load balancing means a heat pump that plays nice with a 100-amp panel.” — Eric Kaiser (paraphrased)

“People, people, people. Comfort is ultimately about humans first.” — Berlin Raj

Berlin on LinkedIn:https://www.linkedin.com/in/berlinrajm/

Totex website: https://www.totexenergy.com/

Come visit with Berin in person at the www.USHeatPumpSummit.com

This episode was recorded in September 2025.

Quotes from the Episode:

“If it helps one person, then it’s worth its weight in gold.” —Roman

“Stop asking ‘What if I fail?’—ask ‘What if I’m amazing at this?’” —Roman

“I ran into the fire and rescued my future self.” —Roman (riffing with Bill)

Roman Baugh—third-generation tradesman, educator at Kalos Services, and prolific HVAC content creator—joins Bill and Eric for a lively conversation that starts with mustache banter and lands on the deeper stuff: curiosity, service, parenting, and learning in public. Roman traces his path from riding along on service calls with his dad to getting humbled by his first big VRF job—then running into the fire to master the technology instead of avoiding it. That mindset led him to teaching, factory-level troubleshooting, and community building.

He discusses homeschooling four boys and how nurturing their curiosity reshaped his own teaching style. Roman shares why he makes no-frills videos and answers techs’ questions at all hours: if one person benefits, it’s worth it. The crew dives into oscilloscopes for diagnosing modern communicating systems, the VRF Tech Talk podcast and Facebook group, and technician-born tools like the EEVmate. Threaded through it all is a simple thesis: chase passion over titles, be okay with failing forward, and find (and become) the helpers.

The episode closes with practical encouragement: stop asking, “What if I fail?” and start asking, “What if I’m amazing at this?” Curiosity compounds; the work finds you; the money follows the value you provide.

EEV Mate products: https://trutechtools.com/eevmate

Roman’s podcast, VFR Talk: https://open.spotify.com/show/1zVYrStAhjzRzCn3oEHE6M

https://podcasts.apple.com/ie/podcast/vrf-tech-talk/id1796450302

https://www.youtube.com/channel/UCcWMzg9BGLvtXJXDO6Yb2BA

Roman on LinkedIn: https://www.linkedin.com/in/roman-baugh-311b21b3/

The Three Pillars Video #!: https://www.youtube.com/watch?v=nxhqW7quyUs

Kalos Services: https://www.kalosflorida.com/

This episode was recorded in October 2025.

Stephen 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.