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MERV vs. Motors

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ECM expert Chris Mohalley joins the podcast to talk about the balance between selecting air filtration and motor performance, also known as “MERV vs. Motors.”

As the industry realizes that filtration is more important, we’re starting to see an interest in filters with MERV ratings of 13 or higher. However, there are some design challenges associated with static pressure drops across filters, motor responses to static pressure, and airflow. If the airflow isn’t set properly, that could affect the refrigerant charge and temperature rise.

PSC motors’ performance directly follows the load; as static pressure increases, the airflow rate produced by the motor decreases. They may also make loud noises when the static pressure is high but satisfactory airflow. However, they are robust and don’t typically fail quickly due to high static pressure.

Electrically commutated motors (ECMs) are operated by electronic controls and come in constant torque or constant airflow varieties. The former has a performance curve (like a PSC motor) but doesn’t appear to suffer from longevity issues when the static pressure is high; the latter can adjust airflow based on static pressure, but it is likely to have issues maintaining airflow during high static pressure conditions. Regardless, there is still an operational envelope; going outside of that envelope will likely result in a capacity and/or efficiency hit if there is high static pressure.

Chris and Bryan also discuss:

COVID-19 pandemic and the evolution of filtration
Face velocity across filters
Amps in constant torque vs constant airflow motors
Swings in airflow/performance
Educating the customer about “upgrading” filters
Using performance manuals

Learn more about Regal Rexnord’s training at https://regal.mmu.com.

Learn more about the 4th Annual HVACR Training Symposium or buy a virtual ticket today at https://www.hvacrschool.com/symposium.

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Heat pumps may be everywhere, but according to David Richardson, the industry is in danger of aiming at the wrong target. In this 2026 HVACR Training Symposium session, the Kentucky contractor’s son, who has never lived in a home without a heat pump, opens with the story of Olympic rifle shooter Matthew Emmons. Emmons hit the bullseye with perfect precision in 2004, only to discover he had fired at the wrong lane’s target. Richardson argues that contractors risk the same mistake when they treat the heat pump itself as the goal and market it with the same “magic” promises used in the 1970s, a pattern that led to poor installations and a reputation problem that has lasted 50 years.

The real target, Richardson says, is the customer, and the heat pump is only one ring on that target alongside ductwork, the building envelope, equipment sizing, noise, and expectations. He distinguishes between HVAC equipment, which anyone can sell, and the HVAC system, which is where a contractor’s skill and craftsmanship show up. Average installations, he notes, deliver roughly 57% of rated performance, while a high-performance retrofit aims for 88% or better. With “free heat pump” offers likely coming next, he urges contractors to differentiate through engagement, education, clear expectations, and measured results, ending with what he calls a “craftsmanship receipt.”

The heart of the talk is five practical tips. First, learn what the customer is really after and set expectations early, including what a defrost cycle looks like. Second, don’t inherit a bad duct system, and use pressure, airflow, and temperature measurements to find problems before they become yours. Third, don’t inherit a bad building, since the structure works like a duct system and can undermine a perfect install. Fourth, bring the customer along by putting simple tools in their hands, such as a thermal camera or flow hood, and translating data into plain language. Fifth, follow a repeatable process that defines where testing begins and where additional paid services start.

Richardson closes with a call to document lessons learned, including mistakes, and to build these practices into company culture. His message is that heat pumps aren’t magic, but they can perform as if they were when installed well and priced to reflect the work. The session wraps with audience questions.

Topics Covered

The Olympic shooter analogy: precision aimed at the wrong target
History of heat pumps, the 1970s energy crisis, and early marketing hype
Why heat pumps shouldn’t be treated as a silver bullet, and the “silver buckshot” approach
HVAC equipment versus the HVAC system
Installation performance benchmarks: roughly 57% for average work, about 6% more for code-approved work, and a goal of 88% or better
The three E’s: engagement, education, and expectations, plus measured results
The craftsmanship receipt and verification: “if you don’t test, you’re just guessing”
Setting customer expectations, including cold-climate performance and defrost
Right-sizing and the pitfalls of oversized equipment, even with inverter technology
Testing for pressure, airflow, and temperature (PAT) and not inheriting bad ductwork
Building science basics: leakage, room pressures, blower doors, and thermal imaging
Using Socratic questions and plain language to involve the customer
Avoiding data overload and using tools like Measure Quick and the TrueFlow Grid
Following a process and getting paid for diagnostics, basic versus advanced retrofits
Learning from mistakes and changing company culture

This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, and Filtrete.

Resources

Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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