ERVs - What you need to know w/ Dr. Bailes

In this episode of the HVAC School podcast, host Bryan sits down with building science expert Allison Bailes to dive deep into the world of Energy Recovery Ventilators (ERVs). The conversation explores the critical role of ventilation in modern homes, highlighting how ERVs have become an essential component of maintaining indoor air quality and energy efficiency. Bailes breaks down the technical nuances of ERVs, explaining how these systems not only bring fresh air into a home but do so while recovering both temperature and moisture energy. The discussion goes beyond simply explaining what an ERV is, delving into the practical considerations of ventilation strategies. Bailes shares personal experiences, including challenges he faced with over-ventilation in his own home, which led to extremely dry indoor conditions. The podcast explores the complex balance of bringing outdoor air inside while managing humidity, temperature, and air quality. Listeners gain insights into why simply bringing in outdoor air isn't always the best solution, especially in climates with extreme humidity or air quality challenges. Throughout the episode, Bailes and Bryan emphasize the importance of thoughtful ventilation design. They discuss the evolution of home construction, noting how increasingly airtight buildings have made proper ventilation more crucial than ever. The conversation touches on key considerations for selecting and implementing ERVs, including motor efficiency, boost capabilities, filtration, and the impact of outdoor air conditions. The experts provide practical advice for contractors, technicians, and homeowners looking to improve their understanding of indoor air management. Key Topics Covered: The difference between Energy Recovery Ventilators (ERVs) and Heat Recovery Ventilators (HRVs) Moisture transfer and vapor permeability in ventilation systems Balanced ventilation strategies and their importance Challenges of over-ventilation and indoor air quality Filtration considerations for ERV systems Impacts of outdoor air quality on home ventilation Strategies for different climate zones The role of ERVs in managing indoor humidity and temperature Resources Mentioned: Allison Bailes' book: "A House Needs to Breathe... Or Does It?" Upcoming online ventilation course from Energy Vanguard (expected May 2025) Energy Vanguard website: energyvanguard.com    Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

In this short podcast episode, Bryan answers a listener-submitted question asking whether you can use another surge protector at the disconnect panel with an ICM 493 already in place. Using multiple surge protectors in the configuration described does NOT count as daisy-chaining. Surge protectors with MOVs (metal oxide varistors) shunt current from high voltage to ground by reducing their resistance. MOVs are sacrificial, so they wear out over time. Surge protectors don't last forever, so installing multiple is a fine idea. You can have whole-home surge protection with additional surge protectors positioned at the appliances/electronics. While it can be done and doesn't hurt anything, it's not the most cost-effective solution.  When you install a surge protector, wire it in parallel with the circuit to ground. It should be wired properly with the shortest possible path to ground. In any case, many surge protectors won't hold up against direct lightning strikes, but they will protect the equipment from power surges after power comes back on or constant overvoltage. Our company, Kalos Services, now uses DITEK's Kool Guard 2 as our surge protector and voltage monitor of choice. They also provide warranties for their products, which have come in handy for customers.   Learn more about the DITEK Kool Guard 2 at https://www.diteksurgeprotection.com/product-series/intelligent-voltage-monitoring/.  Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

In this podcast episode, HVAC professionals Chris Hughes and Adam Mufich discuss the intricate challenges technicians face when commissioning modern inverter-based heating and cooling systems. Unlike traditional single-stage or two-stage HVAC equipment, inverter systems introduce a new level of complexity that can leave even experienced technicians feeling uncertain about proper installation and startup procedures. The presentation highlights a fundamental shift in how HVAC systems operate, moving from straightforward single-stage systems to sophisticated inverter-based technologies that modulate compressor, fan, and refrigerant flow dynamically. This technological evolution creates significant challenges for technicians, who previously could rely on simple, consistent commissioning processes. The speakers emphasize that modern inverter systems require a much more nuanced approach, with specific temperature ranges, wait times, and verification methods that are not always clearly documented in manufacturer manuals. Recognizing the industry-wide need for clarity, Chris and Adam have developed a comprehensive spreadsheet resource that consolidates commissioning information across multiple HVAC brands. Their goal is to empower technicians by providing accessible, standardized guidance for working with these complex systems. By sharing their research and encouraging collaboration, they aim to address what they see as a critical gap in manufacturer support and technical documentation. The podcast serves as both an educational resource and a call to action for HVAC professionals and manufacturers alike. Chris and Adam argue that the industry needs more transparency, better documentation, and a collective effort to standardize inverter system commissioning practices. Their work represents a significant step towards demystifying these advanced HVAC technologies and ensuring that technicians can confidently and effectively install and service modern heating and cooling equipment. Key Topics Covered: Differences between single-stage, two-stage, and inverter HVAC systems Commissioning challenges with modern inverter technologies Critical factors in proper system startup, including: Outdoor and indoor temperature requirements Wait times for system stabilization Refrigerant charging methods Airflow measurement and verification The importance of precise refrigerant charging (superheat and subcooling) Challenges with manufacturer documentation and technical support The need for standardized commissioning procedures across HVAC brands Strategies for verifying system performance during commissioning The speakers' collaborative effort to create a comprehensive inverter system commissioning guide   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

In this short podcast episode, Roman Baugh takes over the HVAC School podcast to answer a listener-submitted question about VRF (or VRV) system evacuation. Evacuation is a critical step of making repairs on VRF systems, which are very diverse and versatile but require a high level of understanding. VRF systems have multiple indoor units per outdoor unit, and they achieve that with the help of several components and accessories down the refrigerant line that can pose issues in evacuation and pressure testing. In heat recovery units, some manufacturers use solenoid valves (or even electronic expansion valves) in branch selector boxes or branch collector boxes. These valves act as little traffic guards, and the system needs to be put in its refrigerant recovery or vacuuming mode. If not, then you won't be able to evacuate all of the refrigerant and non-condensables from the system. Even if the system passes a decay test, contamination is a major concern when the system starts up and the valves open (due to nitrogen and oxygen mixing with pure refrigerant being put into the system). You can trust and verify that the system is in its proper operating mode at the thermostat to ensure that the valves are open 100% and ready for evacuation or pressure testing. Failure to do so not only poses a contamination risk but likely won't maintain its pressure during the pressure test. Assumption or trust alone is not enough. Heat pumps only have two lines, and the vacuum pulls from both sides of the valve. There's less of an issue because there are no branch selector or collector boxes, but it's still good to ensure that the valves are responding and communicating.    Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

This podcast episode is of Bryan's session from the HVAC School Symposium, "10 Things I've Learned in the Last 10 Years." Delivered as HVAC School approaches its 10-year milestone and Kalos hits 20 years, Bryan blends technical know-how with personal stories, revealing how his “expertise” is a product of constant learning—often from the very audience he’s addressing. Bryan’s presentation weaves together practical HVAC lessons and relatable anecdotes, offering a glimpse into his growth as a technician, educator, and leader. He tackles wire sizing versus breaker sizing, debunking outdated myths tied to the National Electrical Code and sharing tales of sparring with inspectors over code-compliant innovations. On vent sweating and duct leakage, he provides actionable fixes—like sealing boots and tackling attic moisture—while urging techs to look beyond bandaids. Bryan also dives into coil corrosion, distinguishing formicary from galvanic causes and advocating for field-driven research over manufacturer spin. His interactive style shines as he pauses for audience questions, fostering a dynamic exchange where attendees refine his insights. The talk balances technical depth with human wisdom, spotlighting patience, joy, and consistency as cornerstones of his journey. Bryan recounts Eureka moments—like unraveling why high-latent markets defy evaporator temperature expectations—and credits mentors like Jim Bergmann and peers like Jordan Cummings for sharpening his perspective. He wraps up with a personal touch, addressing work-life balance as a father of 10 and business owner, advocating for mutual sacrifice with family over unilateral trade-offs.  Topics Covered: Wire Sizing vs. Breaker Sizing: Debunks NEC myths and shares strategies for navigating inspector challenges. Vent Sweating Solutions: Offers practical fixes like sealing boots and managing attic moisture sources. Evaporator Temperature in High-Latent Markets: Explains unexpected suction pressure behavior with lower airflow. Control Layers in Ducts and Walls: Clarifies roles of vapor, air, and thermal barriers in system design. Formicary vs. Galvanic Corrosion: Differentiates coil leak causes, highlighting VOCs and flux issues. Low-Level CO Monitoring: Stresses its importance for safety in homes with combustion appliances. Duct Leakage: Links leaks to moisture and pressure woes, with visual diagnostic tips. Filtration Importance: Pushes for larger, sealed filters over inadequate factory setups. Compression Ratio and Dehumidification: Explores why ductless/inverter systems falter at moisture removal. Personal Growth and Joy: Ties patience, consistency, and community to a rewarding career. Work-Life Balance: Shares lessons on balancing family and work through shared sacrifice.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

In this short podcast episode, Bryan answers a listener-submitted question about using R-290 as a drop-in refrigerant for R-22 systems. It is NOT safe to use R-290 as a drop-in, but there are some similar properties between the two and some interesting thought experiments within this topic. R-290 is propane, a hydrocarbon that belongs to the family of natural refrigerants. R-22 is an HCFC refrigerant that has undergone a manufacturing/importation phaseout in the USA. They are both single-component refrigerants, not blends. Both of them have similar operating pressures and oil carry. However, the latent heat of vaporization of R-290 is almost double that of R-22, which makes it extremely effective as a refrigerant. The main issue with using R-290 is that it is highly flammable and explosive (A3), and it has very small charges (500 grams). Around 2010, some people started selling R-290 blends as drop-in alternatives for R-22. In theory, that combination would work very well, but it is not a safe or legal option. R-290 is currently used in sealed, self-contained equipment. However, it could be the future, especially if our industry goes for refrigerants with lower GWPs and uses flame-free fittings and tubing cutters. It's also worth noting that A2L refrigerants do not contain R-290 or any other hydrocarbons, but it is possible that the industry will gradually embrace the more flammable refrigerants like R-290.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

In this episode of the HVAC School Podcast, host Bryan welcomes Jeff from Copeland to discuss the critical topic of flooding and slugging in compressors. Jeff, calling in from frigid Minnesota (at negative 19°F), explains the differences between these harmful conditions and how they can damage compressor systems. The conversation begins by differentiating between flood back and flooded starts. Flood back occurs during system operation when control of the evaporator is lost, often due to airflow issues. Flooded starts happen after the system has been off, when refrigerant migrates to the compressor oil. Both conditions can lead to slugging - when liquid refrigerant enters the compression chamber, causing immediate damage to valves and internal components. While flood back and flooded starts may cause gradual damage over time, slugging can break compressor components instantly. Jeff emphasizes that proper superheat levels are essential for compressor health, with most Copeland compressors requiring about 20 degrees of superheat at the compressor suction line. The discussion covers various preventative measures, including pump down systems, properly installed crankcase heaters, and the importance of maintaining appropriate refrigerant charge. Jeff notes that many technicians incorrectly assume crankcase heaters are only needed in cold climates, when they're actually crucial for preventing refrigerant migration in any environment. Key Topics Covered: The difference between flood back (during operation) and flooded starts (when the system restarts) How slugging causes immediate damage to compressors while flooding causes progressive damage The importance of maintaining proper superheat (typically 20 degrees at the compressor) Common causes of flood back: dirty filters, improper airflow, duct problems, and incomplete defrosting How refrigerant is attracted to compressor oil even in vapor form Prevention strategies: pump down systems, proper crankcase heater installation and verification The impact of line sizing and total refrigerant charge on system reliability Why compressors are designed for vapor-in/vapor-out operation, not liquid handling The importance of consulting OEM literature and Copeland resources when troubleshooting Why it's critical to identify and fix the underlying cause before replacing a failed compressor   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

In this short podcast episode, Bryan answers a listener-submitted question: what is the best brand of equipment for residential new construction? A lot of people have their own personal preferences when it comes to brands, whether that's with equipment, tools, or even cars. However, when it comes to HVAC equipment, there are a lot of factors that come into play, especially as far as local support is concerned. Are the distributors and territory managers accessible? Reliable? Bryan's personal preferences deal a lot with American (or at least North American) manufacturing and the strength of their local support in the Central Florida market. Some manufacturers have excellent base products but weak product lines, and others have weak base products but great specialized equipment. These judgments come from personal experience, and that's especially true of large manufacturers. Bryan recommends taking a measured, slow approach to products you deal with and then choosing the one that works best for your market and customers. You may find yourself gravitating towards equipment with certain components (like Copeland compressors, for example). You may gravitate towards manufacturers that take feedback about their products and have great local support. The "best brand" really depends on your experiences, values, and business needs.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

Join Bryan Orr and Furman Haynes from WorkHero for a great discussion about how to keep HVAC local and help more small owners succeed. Live from AHR Expo 2025, we get to hear from one of the founders of an exciting new company that is offering expert office management that small HVAC business owners can afford. Bryan also talks with Furman about a survey that HVAC School and WorkHero recently conducted that received over 1,300 responses and yielded fascinating data about the day-to-day challenges of running HVAC businesses. Key topics covered: The challenges small HVAC business owners face with administrative work How the average small business owner spends 15.4 hours per week on non-revenue generating tasks The impact of private equity consolidation on local HVAC businesses How AI and human expertise can work together to support small contractors The importance of preserving craftsmanship and technical excellence in local HVAC businesses Ways to help small business owners focus on growth while reducing administrative burden Whether you're a small business owner looking to optimize your operations or simply interested in the future of local HVAC, this conversation offers valuable insights into maintaining the soul of our industry while embracing new technologies and solutions. Learn about Helping Small Owners Succeed with WorkHero!   View results of Industry Pulse Survey at https://hvacrschool.com/industrypulse/  Work Hero website: www.workhero.pro  Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android  

In this livestream MeasureQuick Talks with Bert. This is an impromptu Talk with industry leaders, including Shelby Breger from Conduit and Joe Medosch from MeasureQuick, about how mobile technology is revolutionizing HVAC diagnostics and training. Featuring special guests discussing how modern tools like MeasureQuick and other diagnostic apps are making it easier for technicians of all experience levels to perform advanced diagnostics and build customer trust. Key Topics: How technicians can leverage mobile technology for better diagnostics Using tablets and phones for real-time HVAC measurements Making technical data accessible and meaningful for customers Bridging the gap between experienced techs and new talent The future of HVAC diagnostics and training How technology can help attract new talent to the trades Recorded live at AHR Expo 2025 with special guests from MeasureQuick and other industry leaders. Whether you're a seasoned pro or new to the trade, learn how modern diagnostic tools can help take your HVAC business to the next level.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android