Episodios

  • Gas & Combustion Safety w/ Bert

    Gas & Combustion Safety w/ Bert
    Jan 29 2026
    In this informative episode, Bryan and Bert dive deep into gas appliance safety and combustion analysis from the unique perspective of Florida HVAC technicians. While they humorously acknowledge that Florida's mild winters mean they don't work on gas furnaces daily, they make a compelling case that this actually makes their training even more critical. When technicians only encounter gas appliances occasionally, the stakes are higher—which is why they've developed rigorous protocols to ensure safety every single time. The conversation covers everything from the basics of gas leak detection to the nuances of carbon monoxide monitoring, combustion air zones, and proper venting. Bryan and Bert share real-world stories of dangerous situations they've encountered, from exploding pool heaters to improperly capped gas lines at vacation rentals. Their approach emphasizes that every gas leak is your problem when you're on site, regardless of why you were originally called out. This episode is packed with practical wisdom for both seasoned professionals working in gas-heavy markets and those who encounter these systems less frequently. Throughout the discussion, the hosts stress fundamental safety principles that apply across all markets: using your nose to detect leaks, understanding the difference between unspent gas and carbon monoxide, ensuring proper combustion air zones, and never ignoring warning signs like delayed ignition or flame rollout. They also tackle common misconceptions about equipment like flexible gas connectors, orphaned water heaters, and the real risks of cracked heat exchangers. The conversation wraps up with important reminders about company lockout/tagout procedures, the critical importance of low-level carbon monoxide detectors, and the tools every technician should carry. Bryan and Bert's candid, no-nonsense approach makes complex safety topics accessible while never losing sight of how serious the consequences can be when gas work goes wrong. Topics Covered Gas leak detection and response protocols - Why every gas leak on site becomes your responsibility, using your nose as the first line of defense, and never leaving a leak for someone else to fixCarbon monoxide safety and monitoring - Understanding CO as a combustion byproduct, the limitations of standard UL-rated detectors, and the critical importance of low-level CO monitorsCombustion air zones and depressurization - Identifying risks from sealed spaces, return air leaks, exhaust fans, and other equipment that can create dangerous negative pressureDelayed ignition and flame rollout - Recognizing warning signs, understanding causes, and why you should never ignore scorched wires or tripped rollout switchesProper gas line assembly and materials - Selecting appropriate materials for different environments, avoiding flexible connector failures, and ensuring proper sizingCombustion analysis fundamentals - Measuring CO levels in the flue, targeting air-free CO under 100 ppm, and understanding when adjustments are neededNatural draft vs. induced draft systems - Differences in safety considerations, orphaned water heaters, and the myth of oversized flue pipesVenting requirements and back drafting - Identifying improper venting, looking for evidence of back draft on water heaters, and ensuring proper flue designGas pressure testing and adjustment - When to adjust and when not to, reading data tags, and understanding that most flame problems are air-related, not gas pressureCracked heat exchangers in context - Why they're less common in warm climates, the role of proper airflow, and focusing on actual safety risks vs. edge casesTools and equipment recommendations - Combustion analyzers, personal protective CO detectors, combustible gas detectors, precision manometers, and low-level CO alarms Lockout/tagout procedures - Following company protocols, communicating clearly with customers, and balancing safety requirements with homeowner autonomy 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 7th 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.
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    45 m
  • WHY SQUARE FOOTAGE ≠ TONNAGE - Short #276

    WHY SQUARE FOOTAGE ≠ TONNAGE - Short #276
    Jan 27 2026

    In this short podcast episode, Bryan dives a bit into equipment sizing rules of thumb and why square footage does NOT equal tonnage in today's world. Many rules of thumb exist in the industry, and one is a load calculation rule stating that you can size the HVAC for a house at 500 square feet per ton.

    Old houses are leaky and poorly insulated compared to new homes, which results in large energy loads but allows the homes to dry themselves out, as moisture could leak out before it could cause trouble indoors. Large loads and leaky envelopes made 500-600 square feet per ton a sensible rule.

    Homes built within the last few decades have a lot more insulation and are tighter, and they have smaller sensible heat loads. However, they're a lot more moisture-prone, especially when moisture can't escape via proper ventilation paths. The 500 square-foot rule of thumb overshoots the latent capacity and leads to short cycling due to oversized equipment. Enter ACCA Manual J, which presents a load calculation method that is very good, but it has barriers to entry; it is very rigorous, has a learning curve, and can be a hassle. One thing is clear, though: load management is key, especially latent load management.

    At this time, we measure energy efficiency in terms of metrics like SEER, but the future is pointing to peak load management as the answer: getting the right power draw at the right moments instead of high general efficiency. Modernizing hot deck-cold deck systems with steady-state, constantly running systems might be the way to go, especially if we utilize energy storage and modern variable-speed technologies.

    The new rule of thumb is to think like a building scientist and apply new tools to concepts that have stood the test of time. Low peak loads and steady-state operation are often the way to go with high latent loads in homes built to the most recent building codes and standards.

    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 7th 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.
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    13 m
  • EPRs and Rack Refrigeration w/ Matthew Taylor

    EPRs and Rack Refrigeration w/ Matthew Taylor
    Jan 22 2026
    Matthew Taylor delivers an expert-level presentation on EPRs, building on his previous work on parallel rack systems. While his earlier content focused on the similarities between air conditioning and refrigeration, this session explores what makes commercial refrigeration unique—particularly the critical role of EPRs in maintaining optimal operating conditions across multiple evaporators running at different temperatures. This presentation was shared at the 6th Annual HVACR Training Symposium. The discussion begins with a fundamental review of the refrigeration cycle in a typical supermarket setting, where 30 to 80 evaporators may share a common suction line. Matthew explains why EPRs are essential: when multiple cases need to operate at different temperatures (ranging from -13°F for frozen foods to 24°F for fresh products) but all connect to the same compressor rack, EPRs become the solution that makes this possible. Without them, cases would cycle on and off constantly, creating efficiency nightmares, oil management problems, and potential food safety issues. Matthew walks through the mechanical principles of various EPR types, from the high-efficiency Sporlan SORIT valve with its pilot-operated design to the Parker A8 valve that can be installed directly in the store. He also addresses the industry's shift toward electronic EPRs, particularly the CDS modules that offer temperature-based control rather than just pressure regulation. Throughout the presentation, Matthew emphasizes practical considerations: how EPRs affect compressor staging, oil system pressure, defrost cycles, and ultimately, the core product temperatures that determine food safety. The session includes real-world troubleshooting insights and addresses common misconceptions about setting superheat on systems with EPRs. This technical presentation provides HVAC professionals with the knowledge needed to understand, diagnose, and service EPR-equipped refrigeration systems confidently. Matthew's approach demystifies a component that many technicians find intimidating, breaking it down into understandable principles while highlighting the critical role EPRs play in modern commercial refrigeration efficiency and reliability. Topics Covered Basic Refrigeration Cycle in Supermarket Applications – Understanding parallel rack systems with 30-80 evaporators sharing common suction and liquid linesOil Management Systems – Oil separators, oil reservoirs, oil regulators, and the critical pressure differential required for proper oil flowCompressor Staging and Capacity Control – How parallel rack compressors operate as multi-stage units to match system load efficientlySaturated Suction Temperature (SST) – Why racks are designated by temperature (e.g., "13-degree rack" or "-13 degree rack") and how this relates to the coldest evaporator requirementTemperature Difference (TD) Engineering – The relationship between evaporator temperature and case leaving air temperature, typically 10 degrees in traditional systemsEPR Fundamentals – Why EPRs are necessary to maintain different evaporator pressures on cases operating at various temperatures while connected to a single rackMechanical EPR Types – Comparison of Sporlan SORIT valves (pilot-operated, low pressure drop) versus Parker A8 valves (self-contained, higher pressure drop)Electronic EPR Systems – Modern CDS modules and other electronic controls offering pressure control, temperature control, or hybrid approachesSystem Stability and Load Management – How proper EPR settings prevent compressor hunting, reduce energy consumption, and protect oil management systemsSubcooling Requirements – Why liquid receivers eliminate natural subcooling and how mechanical subcoolers restore it before expansion devicesCore Product Temperature – The critical relationship between runtime, EPR settings, and food safety in refrigerated cases Dual-Temperature Applications – Converting medium-temp cases to low-temp operation (like holiday turkey displays) using EPR pilot solenoidsSuperheat Setting Procedures – Why EPRs must be overridden to 50-100% open position when setting TXV superheatHigh Glide Refrigerants – Special considerations for setting EPRs with refrigerants that have significant difference between dew point and bubble point temperatures Troubleshooting Philosophy – Understanding EPRs and TXVs as independent systems that don't directly affect each other due to non-critically charged liquid receiver systemsPressure Drop Considerations – How EPR pressure losses (0.5-2 psi depending on type) affect compressor suction setpoints and energy efficiencyElectronic Control Integration – Various controller brands and approaches to managing electronic EPRs, from pressure transducers to temperature sensors and PID algorithms 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...
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    55 m
  • Combustion vs. Compression - Short #275

    Combustion vs. Compression - Short #275
    Jan 20 2026

    In this short podcast episode, Bryan covers the history of the great heating debate: furnaces vs. heat pumps or combustion vs. compression. He also gives a breakdown of each other's strengths and gives his two cents on the winner of the debate.

    Fire kept humans warm for much of history, but engineers developed a way to move heat by manipulating refrigerant pressures. Early heat pumps got a bad rap because they didn't live up to the hype; they had frequent operational issues, didn't heat effectively, and were largely unable to be serviced effectively by technicians.

    However, heat pumps have evolved and now outperform furnaces in many areas. Ones with COPs between 2 and 5 can be anywhere from 200-500% efficient in terms of watts in, BTUs out. They also have many safety benefits over gas furnaces, including no risk of flame rollout, carbon monoxide poisoning, and gas leaks; removing the gas meter and all its risks entirely is a possibility.

    Nevertheless, some people still insist that combustion is king due to its comfort, as furnaces' heat is more intense than that of heat pumps. Furnaces also require little electricity, making them more sensible in markets with weak or dirty electrical grids. Combustion appliances also only need to work part of the year, meaning they run fewer cycles and experience less mechanical wear over the same period of time as heat pumps (thus may have longer lifespans).

    Dual fuel allows you to get the best of both worlds; it allows the heat pump to handle the cooling and most of the heating for the energy efficiency benefits, and the furnace can step in when more intense heat is needed. Ultimately, the "winner" of this debate, at least to Bryan, is the most sensible solution for energy costs, safety, comfort, and reliability; the real answer will depend on the climate, infrastructure, and other factors.

    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 7th 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.
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    12 m
  • HVAC In the Northeast w/ Leo & Paul Sharkey

    HVAC In the Northeast w/ Leo & Paul Sharkey
    Jan 15 2026
    In this engaging episode of the HVAC School podcast, host Bryan Orr sits down with Leo and Paul Sharkey, a father-son duo of mechanical engineers who made the leap into the HVAC business. Leo and Paul share their remarkable journey of purchasing an HVAC company in September 2020 and quadrupling its revenue within five years. Their engineering backgrounds bring a refreshing, data-driven perspective to an industry that often relies on rules of thumb and outdated practices. The Sharkeys operate in the challenging Northeast market, where homes can date back to the 1600s and 1700s. They discuss the eye-opening discovery that traditional HVAC sizing methods—like the simplistic "one ton per 400 square feet" rule—fail dramatically in older housing stock. Their commitment to running thousands of Manual J calculations has transformed their approach, often resulting in smaller, more efficient systems than competitors propose. The conversation dives deep into the unique challenges of working with centuries-old New England homes, including extreme infiltration rates, non-linear heat loss curves during harsh winters, and the complications of mixing modern additions with ancient construction. Beyond sizing, Leo and Paul tackle the practical realities of heat pump installations in cold climates. They explain why turndown ratio is critical, how they handle homes with heat loads that triple their cooling loads, and when backup heating systems are truly necessary. Their consultative approach rejects the "one-size-fits-all" mentality that has flooded the market with incentive-chasing installations. They candidly discuss the problems created by Massachusetts' generous rebate programs, which have attracted fly-by-night operators who prioritize rebate qualifications over proper design and long-term performance. The episode also explores the balance between ductless and ducted systems, revealing when each approach makes economic and technical sense. The Sharkeys share fascinating case studies, from a 1748 house with the equivalent of a full-size door's worth of air leakage to underground concrete dome homes requiring specialized dehumidification. Their willingness to take on complex projects that other contractors avoid demonstrates how engineering thinking, combined with trade expertise, can solve challenging HVAC problems. This conversation is essential listening for anyone serious about understanding cold climate HVAC design, building science principles, and what it takes to deliver quality comfort solutions in real-world conditions. Topics Covered Engineering background transition to HVAC - How mechanical engineering experience in semiconductors and manufacturing informed their HVAC business approachManual J calculations and proper sizing - Running 7,000-9,000 Manual J calculations over five years and why they typically specify smaller systems than competitorsOld New England housing challenges - Working with homes from the 1600s-1700s, extreme infiltration rates, and heat loss characteristics of ancient constructionHeat load vs. cooling load imbalances - Managing homes where heat loads can be triple the cooling loads and how this affects system designHeat pump turndown ratios - Why equipment turndown capability is critical for shoulder seasons and preventing short cycling in cold climatesCold weather performance and derating - Equipment capacity loss at low ambient temperatures and the importance of proper backup heat sizingDuctless vs. ducted system economics - When to choose multi-zone ductless over ducted systems based on home layout, infrastructure, and costRetrofit complications in mixed construction - Dealing with homes that combine 200-year-old sections with modern additions on the same heating system Massachusetts incentive programs - How Mass Save rebates (up to $25,000 financing + $10,000 rebates) have impacted market quality and contractor behaviorInstallation challenges at low temperatures - Field issues including undersized ductwork, poor equipment placement, defrost cycle complications, and electric backup heat requirementsBuilding science fundamentals - Blower door testing, weatherization impacts, infiltration effects on heat load, and wind loading considerationsConsultative sales approach - Rejecting one-size-fits-all solutions and customizing system recommendations based on home characteristics and homeowner needsBackup heating strategies - When and why fuel-based backup systems are necessary, including power outage considerations and client comfort levelsComplex project examples - Case studies including underground concrete dome homes, storage closet air handler installations, and severely under-designed retrofit corrections Learn more about Leo and Paul's business, Jay Moody HVAC, at https://jaymoodyhvac.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 7th Annual ...
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    37 m
  • Superheat in Heat Mode: Why Heat Pumps Get Weird - Short #274

    Superheat in Heat Mode: Why Heat Pumps Get Weird - Short #274
    Jan 13 2026

    In this short podcast, Bryan answers a listener-submitted question and explains why heat pumps get a bit weird: when it comes to superheat in heat mode. He also explains how we can move heat from outdoors to indoors, even in temperatures below freezing (cold temperatures just have less heat, not zero heat).

    In order to move heat in very cold conditions, we need very low suction pressures and cold coils, which gives us a high compression ratio. Superheat will be affected by these conditions. Remember: superheat that is too low can cause floodback, and superheat that is too high can cause the compressor to overheat.

    Superheat is easy to check in cooling mode, but it's harder in heating mode, especially since the suction line is at the outdoor unit. In heating mode, we can only measure superheat between the coil outlet and the reversing valve inlet, which is a very short run of tubing.

    The superheat will also be less stable in heat mode in cold weather, and it will have a wider range of "normal" values than cooling mode, depending on the conditions. Superheat could even drop to zero with some fixed-orifice metering devices (which would cause floodback). That's why many of these heat pumps have accumulators, which collect liquid refrigerant to protect the compressor. Even though TXVs attempt to maintain superheat, you may still see some variation in heat mode during cold weather. EEVs are common in ductless systems and are highly controllable but maintain relatively low superheats by design; fast metering control, intelligent logic, accumulators, and low refrigerant charges allow them to avoid floodback in low temperatures.

    In any case, spikes and drops in temperature can cause the superheat to jump or collapse because the load changes (as the outdoor coil is the evaporator). Frost buildup on the coil also inhibits airflow and heat transfer, causing the superheat to change as the evaporator pressure and temperature drop. Defrost also introduces chaos to the equation. All of these should influence your judgment when checking superheat to diagnose or commission a system in heat mode.

    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 7th 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.
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    15 m
  • What We Learned From NCI Duct / Balancing Training

    What We Learned From NCI Duct / Balancing Training
    Jan 8 2026
    In this engaging and informative episode, Bryan sits down with Elliot to discuss his recent training experience with the National Comfort Institute (NCI), covering two intensive courses on duct system optimization and residential air balancing. The conversation offers valuable insights for HVAC professionals looking to improve their technical skills and provide better service to their customers. With a mix of technical expertise and practical field experience, this episode breaks down complex HVAC concepts into actionable strategies for contractors and technicians. Elliot shares his key takeaways from the NCI training, emphasizing how the courses filled critical knowledge gaps about the "invisible stuff" in HVAC systems—the air itself. The discussion reveals a common industry problem: most HVAC professionals focus heavily on equipment while neglecting proper duct design and air balancing. Elliot explains how he learned to move beyond guesswork in duct design, discovering that flex duct has actual CFM ratings and that proper system design requires understanding static pressure, equivalent length of fittings, and the science behind airflow. The conversation highlights the importance of oversized return air systems—a point both hosts stress repeatedly—and explains why Florida (and possibly the entire nation) suffers from chronically undersized returns. The hosts discuss various duct system approaches, from traditional trunk lines to the flex-and-fitting systems, acknowledging that different markets require different solutions based on climate, building construction, and supply chain availability. Throughout the episode, Bryan and Elliot tackle practical installation challenges that technicians face daily. They discuss the importance of proper flex duct installation, explaining how compressed or sagging ductwork dramatically reduces airflow efficiency. The conversation covers the critical role of balancing dampers in every branch run, the impact of proper duct strapping, and how simple adjustments like straightening kinked flex duct can immediately improve CFM delivery. The hosts also address the limitations of builder-grade installations, noting that most new construction lacks the dampers necessary for proper air balancing. They emphasize a practical, process-based approach to HVAC work that focuses on getting clients measurable results without requiring perfect conditions or unlimited budgets. The episode concludes with a strong endorsement of the National Comfort Institute's training programs and tools, particularly the TrueFlow Grid and measureQuick technologies that simplify complex air balancing calculations. Bryan and Elliot stress the importance of ethical, high-performance contracting that delivers real value to customers rather than just marketing sizzle. They encourage HVAC professionals to invest in training and proper tools, acknowledging that while the initial investment may seem steep, the ability to provide superior service and reduce callbacks makes it worthwhile. The conversation serves as both a technical deep-dive and a call to action for contractors to elevate their skills and focus on the whole system—equipment, ductwork, and building envelope—to truly solve customer comfort problems. Topics Covered NCI Training Experience - Elliot's overview of the duct system optimization and residential air balancing courses, including instructor quality and course relevance to Florida's HVAC marketDuct Design Fundamentals - Moving from guesswork to calculated design using CFM ratings, square footage calculations, and proper system output considerationsStatic Pressure Management - Understanding static pressure drop across coils, the importance of variable speed fans, and strategies to reduce total external static pressureReturn Air Systems - Why bigger returns are always better, the critical importance of oversized return grills, and the impact of filter face velocity on system performanceEquivalent Length of Fittings - How fittings add "phantom" duct length to runs, techniques to reduce equivalent length, and the dramatic impact of turning vanes on 90-degree turnsFlex Duct vs. Trunk Lines - Comparing different duct system approaches across various markets, the pros and cons of metal, duct board, and flex systems, and the flex-and-fitting methodologyProper Flex Installation - The importance of stretching flex duct correctly, proper strapping techniques, and how sagging or compressed flex drastically reduces airflowAir Balancing Techniques - The necessity of balancing dampers in every branch run, methods for achieving proper air distribution, and using velocity comparisons for troubleshootingThrow and Mixing in Rooms - Understanding that grills, not duct size, control air throw and mixing, and the role of Manual T in selecting appropriate terminal devicesPractical Installation Tips - Simple improvements technicians can make during service calls, like straightening kinked ...
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    37 m
  • HVAC Systems for Architects: Making Sense of the Alphabet Soup - Short #273

    HVAC Systems for Architects: Making Sense of the Alphabet Soup - Short #273
    Jan 6 2026
    In this short podcast, Bryan answers a question submitted to HVAC School by an aspiring licensed architect who wanted to learn more about the many different types of HVAC systems. The three main buckets of HVAC systems are air-to-air, water-source, and air-to-water. Air-to-air systems move air around to remove heat from one space, and that heat is rejected to the air somewhere else. Water-source systems move water around the building and use water as the heat rejection medium. Air-water hybrid systems condition the load with water and may use air for ventilation; water or air may be used as the rejection medium. Systems may be direct-exchange (DX) and may transfer heat directly to refrigerant, or they may flow the air or water over a coil with water or glycol, utilizing a secondary fluid. Systems may also have separate indoor and outdoor architecture (split systems), or all components may be rolled into a single box (package unit). Package units include window units, PTACs, and RTUs. When it comes to forced-air systems, constant air volume (CAV) systems maintain the same volume of airflow (though the temperatures will change). Variable air volume (VAV) systems use one stream of cold air in a main duct, and each zone has a VAV box that functions as a damper to control zones individually. Dual duct systems have one cold duct and one warm duct that run parallel to each other and mix at each zone. Packaged rooftop units (RTUs) are self-contained with ducts that run down into the space and are common in retail spaces. Air-to-water systems use fan coil units (FCUs) fed with chilled or hot water. Air moves locally inside the space, so there is less ductwork and good zone control, but there are many units to manage. Chillers make chilled water, and that water is pumped around the building and sent to individual air handler units (AHUs). These are highly efficient and have large amounts of piping. They need mechanical rooms and dedicated personnel to maintain them. Variable refrigerant flow (VRF) systems are DX systems that are becoming more popular and consist of multiple indoor units with one or more outdoor units. Some of these can be used for heat recovery, meaning one space can be cooled while another is heated. Heat pump types include air-source, water-source, and ground-source. Air-source heat pumps absorb heat from the air via one unit and reject it via the other; the outdoor and indoor units can swap functions. Water-source heat pumps are common in commercial applications and have multiple heat pumps tied into a water loop that tries to stay within a given temperature range via boilers and cooling towers. Ground-source or geothermal heat pumps pick up heat from the earth's stable temperature and are highly efficient, but they have high installation costs. Passive systems come in all sorts of varieties and reduce the HVAC system's loads but don't replace HVAC systems in North America. Mechanical systems consist of straight-cool (air conditioner with electric heat), furnaces (gas, propane, or oil combustion), or heat pump (reversible air conditioners) systems. 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 7th 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.
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    20 m