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Measuring the invisible has never been an easy task, but the practice is an absolute necessity in order to deliver a high-efficiency HVAC system that functions as it was designed to.

Speaking at the AHR Expo in Chicago, David Richardson, vice president of training at the National Comfort Institute Inc., and Chris Hughes, business development manager at The Energy Conservatory, explained that with new technology, measuring airflow has become easier to do and, with software and other automation, even easier to understand.

With these new tools at their disposal, HVAC contractors should routinely incorporate airflow measurement into all new construction jobs and maintenance calls sooner rather than later because, eventually, the customer is going to start demanding it.

A Step Back through Time

Sometimes to better understand a concept, it’s best to start at the beginning. For pioneering HVAC technicians, the process of measuring airflow was time-consuming, difficult to quantify, and perhaps even more difficult to explain to those outside of the industry, meaning they weren’t always a standard procedure.

“Of all the measurements we can take in our industry, airflow is probably the most challenging,” Richardson said.

But Richardson explained even in its infancy, airflow measurement helped to define the stark differences between what was defined as the equipment and the system — a line that is still blurry for most contractors today. The system, in short, is how the overall apparatus works in concert to create a desired outcome.

“The equipment is a component of the system,” Richardson said. “We’ve been brainwashed into calling the equipment the system, and the system is far from it.”

These early methods of airflow measurement occasionally required manhandling heavy equipment or drilling into areas that strained nerves. Because of these inconveniences, many HVAC techs simply stopped getting the readings.

Unfortunately, a lot of that stigma still exists within the industry, but new tools and techniques have come onto the scene at a pivotal point in HVAC history and are poised to usher in a new era where these measurements are easier to take and implement than ever before.

Why it Matters

Hughes said he came from a family business where that name on the side of the truck told people they could trust the work that was being done. But, he said, the days of that “good old boys system” are quickly coming to an end, because now, people are going to start wanting to see the data before signing off on a job.

“Customers are starting to figure out that there’s now technology that produces customer-friendly reports,” Hughes said. “You better get ready, because they’re going to start asking for it.”

With those numbers being more accessible, even the most beautifully installed system is going to be rejected if it’s not producing the numbers it's supposed to, as airflow rates, static pressure, and proper duct optimization are key to ensuring the system works as promised.

The current push toward optimal energy efficiency will also likely drive the further implementation of airflow technology, as it's top of the mind for both manufacturers and consumers.

Impact on the Industry

When it comes to a properly working system, the buck often starts and stops with the installer.

EFFICIENCY LANDS ON THE INSTALLER: David Richardson told attendees of an educational session that their installers have more control over the real-world efficiency of any given unit than whatever the label says. (Staff photo)

“If you guys are putting it in, you control the efficiency more than the yellow label on that box — don’t let anybody convince you otherwise,” Richardson said.

As installers, accuracy can be improved severalfold, and troubleshooting simplified by introducing effective airflow measurement into the equation.

“I think most of us would acknowledge that most designs fail to perform as designed. … Most airflow data, most airflow information is written for engineers, by engineers,” Richardson said. “You may have something that looks wonderful on paper, but as soon as you pull out the measurements, you can’t hide from them — they make that design transparent.”

Although finding out the newly installed system isn’t working as intended and needs to be troubleshooting is certainly a phone call a contractor wants to avoid, airflow measures don’t always spell bad news.

Using airflow technology to quantify the capability of a system that is working as intended is beneficial not only to the client, but also to the hands that put it together.

“Installers get to see they do better work,” Richardson said. “They start to take pride, they start to understand why they’re doing what they’re doing. You get to see the results of that craftsmanship.”

Hesitation to Implement

Richardson said the No. 1 barrier to implementing this practice isn’t testing instruments, lack of skillset, or money — it’s fear. It’s that potential hissing sound made after the hole is drilled to take the measurement.

“Guys are worried they’re going to drill into the coil because [that’s] one of the essential measurements to static pressure diagnostics,” Richardson said.

In most instruction manuals provided by manufacturers to measure static pressure, they show the pressure entering the coil right at the delta plate, where all the cap tubes and the expansion valve are located. Richardson joked that the people who suggest the measurement is taken at that junction are probably the same people selling coil.

There are easier, and potentially less catastrophically-damaging, methods, Richardson said, but the big barrier is actually getting techs to do them.

When Richardson implemented consistently measuring airflow as part of his crew’s everyday work, he said all his guys heard was two words — more work.

He tried to incentivize them in every way he could think of, but they still just weren’t taking the measurements he wanted.

“If you’re going to teach your guys to do this, start small. And when you think you’ve gone small enough, go smaller,” Richardson said.

Coil inspection was something they did on every job, so he asked how long they estimated that took them.

“They said, ‘At least 10 minutes.’ I said, ‘What if I could show you how to determine if that coil was dirty in less than a minute?’ Now they were all ears,” he said. “Drill a hole before the coil, drill a hole after the coil. Pressure in, press out, subtract them. If it’s over this number, visually inspect the coil; if it’s not, you’re probably good.”

The key is to help technicians understand why, and only then will they change how they do things.

“If they hear ‘more work,’ you’re doomed,” Richardson said. “If they hear ‘make my work easier,’ they’ll run through a wall for you. And that’s what testing should do — it should make your life easier.”

The Future

All the talk of airflow measurement ties into the industry’s next big challenge — the heat pump.

With the IRA money and all the rebates hitting the ecosystem, heat pumps are set to continue gaining popularity. In a lot of cases, those heat pumps are going to be part of a retrofit, which poses its own unique challenges that will require airflow measurements to solve.

Hughes gave a hypothetical where there was a 40,000 BTU furnace that a customer wanted swapped with a 36,000 BTU heat pump.

“When you used to do a retrofit, you’d be going furnace to furnace, and typically, the airflow was going to be about the same,” Hughes said. “But when you go from furnace to heat pump, you go to move a lot more airflow — like three times as much.”

Now contractors have to consider how existing duct systems are going to respond — is it going to be big enough? That’s the new million-dollar question.

With new technology, contractors may be able to figure out the potential efficiencies before even tearing apart the system — and know what needs to be retrofitted or if things like air returns need to be added. This is especially important if the system is going to be more relied upon to provide heat.

“By taking these measurements, it gives you that confidence to go in and make these changes,” Richardson said.