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The VOCs Lurking Under Your Customers’ Sinks (and In Many Other Spots)
Another Ob-NOx-ious Combustion Product
How to Replace a Condensing Fan Motor
Design and Performance Challenges of Air-Source Heat Pumps Across Diverse Climatic Conditions
Brownouts and How They’re Killing HVAC Equipment
CAT Ratings on Electrical Multimeters
AHRI Performance Data vs. Manufacturer Expanded Performance Data (and When to Use Each)
Field Guide to Crankcase Heaters
What Makes a Thorough Comfort Consultation
Tech Support Highs and Woes w/ Roman
The Current War – Tesla, Edison & Westinghouse – Short #266
An R-454B Ramble w/ Elliot
Psychrometrics and the Magic Line – Short #265
Learning Hydronics, Boilers and Steam w/ Ray Wohlfarth
How Duct Tape Got Its Name (and Why It Shouldn’t Be on Ducts) – Short #264
The Art of De-Escalation
Legionnaires’ Disease: The Cooling Tower Killer – Halloween Short #263
Group Training – What We Have Learned
#hvac
Tech Tips:
In HVAC, we have a few infamous indoor air quality monsters that bring terror to our customers’ homes—gases, particles, and organisms that wreak havoc on indoor air quality (and may contribute to moderate to severe health problems). The big one is carbon monoxide (CO), which we all know is deadly. Although not deadly by itself, […]
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As we do fall maintenance and head into the heating season, combustion analysis becomes a big deal. (It’s always kind of a big deal, but now it’s a really big deal.) First and foremost, it tells us how much carbon monoxide (CO) is produced by burning. CO can make people ill, contribute to cognitive deterioration […]
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Service calls about condensing fan motor failure are quite common. Even though fan motor replacement is a standard procedure for residential split systems, it requires careful attention to safety and detail. This article will give you a step-by-step guide showing how to replace a condensing fan motor. Along the way, we will also explain a few […]
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This tech tip was inspired by Alex Meaney and Ed Janowiak’s session at NCI’s High-Performance Summit 2025: “Good Design Isn’t a Buffet: The Importance and Interconnection of Manuals J, S, and D.” Alex is a building science expert who worked at Wrightsoft (now MiTek) for several years before launching his consulting firm, Mean HVAC Consulting […]
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HVAC technicians typically focus on diagnosing issues related to mechanical wear, refrigerant leaks, or control problems within the equipment. However, damage can also originate from external sources. For instance, a failed control board might be attributed to internal shorts or rubouts. Yet, the root cause could be external, such as the voltage spike that can […]
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If you have a multimeter for HVAC work, you most likely have a meter with a CAT III rating on it. Some might also be rated for CAT II at higher voltages or CAT IV at lower ones—or both, like this model of the UEi DL599 from our Multimeter 101 for HVAC 3D video. In […]
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Equipment selection may seem like a pretty straightforward process: look at the data plate, find the tonnage that’s close to your Manual J calculation’s total load, and you’re good to go, right? The problem with that approach is that a 3-ton unit won’t deliver 36,000 BTUs per hour like it says on the data tag. […]
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Crankcase heaters are a critical but often overlooked component in air conditioning and refrigeration systems. Their function is simple but vital: to prevent liquid refrigerant from migrating into the compressor crankcase during the off-cycle. A missing or failed crankcase heater is a leading cause of premature compressor failure. This guide covers why they're necessary, how […]
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This tech tip is based on an HVAC School podcast episode with Tim De Stasio. Tim has written several articles about HVAC design on his blog, several of which he has been generous enough to share with HVAC School. Tim’s focus is on humid climates, and moisture mitigation is one of his main focuses in […]
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Videos:
Podcasts:
In this candid and comprehensive episode, Bryan sits down with Roman to tackle one of the most frustrating yet crucial aspects of the HVAC industry: technical support. What starts as a conversation about their own tech support nightmares quickly evolves into a deep dive examining the entire ecosystem—from manufacturers and distributors to technicians and […]
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In this short podcast episode, Bryan is back for yet another history lesson. This time, the subject is the current war with Tesla, Edison, and Westinghouse. The current war was fought in the late 1800s with lightbulbs, electrocutions, and a World's Fair that dazzled the entire world. Edison didn't necessarily invent the lightbulb, but […]
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In this raw and unfiltered episode, Bryan sits down with Elliot, a senior service tech and newly minted install supervisor, to discuss the realities of working with R-454B refrigerant in the field. What starts as a technical discussion about the new A2L refrigerant quickly evolves into a candid conversation about industry frustrations, manufacturer accountability, […]
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In this short podcast episode, Bryan talks about psychrometrics and the magic line inside a messy-looking chart. The psychrometric chart is a key tool for understanding the relationship between air and water. “Psychrometric” comes from the Greek roots for “cold” and “measurement.” As such, a tool called the psychrometer (with paired wet-bulb and dry-bulb […]
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In this episode of the HVAC School podcast, Bryan sits down with Ray Wohlfarth, a seasoned HVAC contractor and prolific author who has dedicated over 30 years to mastering the art and science of boiler systems. What began as a competitive disadvantage—competitors claiming he knew nothing about boilers—became Ray's driving passion. Through daily reading, […]
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In this short podcast episode, Bryan explains how duct tape got its name and why it shouldn't actually be used on ducts. Duct tape is a versatile home DIY-fix tool, but despite its name, it wasn't initially made to seal ducts at all. In 1943, we were in the thick of World War II, […]
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In this comprehensive discussion, Bryan and Bert tackle one of the most critical yet underdeveloped skills in the trades: conflict resolution and de-escalation. They argue that poor conflict management is one of the primary reasons technicians lose jobs, damage team dynamics, and limit their career advancement. The conversation explores both customer-facing conflicts and internal […]
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In this spooky Halloween short podcast episode, Bryan tells the story of the cooling tower killer: Legionnaires' disease. In the summer of 1976, the nation celebrated its bicentennial anniversary. The American Legion was holding its 58th annual convention at the Bellevue Stratford Hotel in Philadelphia, PA. In the days following the convention, doctors in […]
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In this episode of the HVAC School podcast, Bryan Orr sits down with Bert and Leanna to discuss Kalos's first official cohort apprenticeship program, dubbed the “Launch Program.” What started as Bryan's persistent idea—one that the team initially resisted as too expensive and logistically challenging—evolved into a transformative three-month training experience that brought 15 […]
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