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For the last several years, the HVACR industry has been laser-focused on the AIM Act, which gave the Environmental Protection Agency (EPA) the authority to phase down the consumption and production of high-GWP HFC refrigerants by 85% by 2036. As part of that rule, EPA is mandating a 700 GWP limit for most new comfort cooling equipment starting January 1, 2025. From that date forward, manufacturers will be prohibited from producing air conditioning or heat pump systems that utilize R-410A, which has a GWP of 2,088. Instead, those systems must be manufactured using low-GWP alternatives such as R-32 and R-454B, both of which are mildly flammable (A2L).

With the impending deadline right around the corner, manufacturers have started introducing their A2L systems in the U.S., so the time is now for contractors and technicians to learn how to install and service equipment containing these new refrigerants.

Training and Best Practices

The fastest way to get up-to-speed on learning how to safely install the new A2L systems is to take a training course from a reputable source, such as ESCO Institute, ACCA, NATE, or any of the HVAC or refrigerant manufacturers. The training is often online, inexpensive, and — given the mild flammability of the new refrigerants — crucial to ensuring technician and customer safety, said Jason Obrzut, director of industry standards and relations at ESCO Institute.

“A2L training has been available for several years now,” he said. “These programs are very successful, and you can’t go wrong with any of the reputable training sources.”

While there are currently no federal requirements mandating A2L training or certification, that could change in the future, as many trade associations and manufacturers have expressed concern over the lack of such requirements in EPA’s “Management of Regulated Substances,” which falls under subsection (h) of the AIM Act. In addition, there are some supply houses around the country that are requiring training before they will sell someone an A2L system, said Obrzut.

Another benefit to taking a reputable training program is that it can serve as an antidote for those who are nervous about installing one of the new A2L systems. As Obrzut said, “Get some training. You’ll feel better.”

Contractors and technicians will also feel better understanding that the new A2L systems are not all that different to install than R-410A systems. According to Obrzut, “A lot of the things that used to be required by the manufacturer — or what we consider to be best practices — are now required by code. They're mandatory, which they really should have been from the beginning.” These best practices include purging the circuit with an inert gas (e.g., nitrogen), evacuating the circuit, and leak and pressure testing the unit.

Another difference with A2L systems is that those containing more than 4 pounds of refrigerant will require a refrigerant detection system (RDS), which may be factory or field-installed. Per the safety standards, the RDS must self-test every hour to “sniff” for a predetermined concentration of refrigerant. If that concentration is reached, the RDS will signal the HVAC equipment to activate mitigation measures, such as turning off the outdoor unit to stop the refrigerant flow and turning on indoor unit fans and blowers to reduce the refrigerant concentration to a level well below the flammability limit.

“Every brand will handle the RDS differently, so it would behoove contractors and technicians to take that manufacturer’s training,” said Obrzut. “Contractors and technicians are also supposed to test the RDS to make sure that it works the way it's supposed to, such as turning on the blower, de-energizing the condenser, etc. Just remember that they're all going to operate a little differently.”

The charge size will also vary depending on the application, as the maximum charge size for A2L equipment will be limited by the cubic feet of airspace that is served by the equipment. Essentially, the installation space or the house must be large enough and have enough air to keep the refrigerant at or below a percentage of the lower flammability limit (LFL) should the entire charge leak into the space, said Obrzut. To ensure their products are installed correctly, manufacturers will include sizing and charging charts in their installation manuals, and some are even offering apps to simplify this process.

One more best practice that contractors and technicians should follow when installing an A2L system is to properly recover and recycle the R-410A that was in the system they are replacing.

“Recover the 410A — it's worth money,” said Obrzut. “All the reclaimers are paying top dollar for these clean HFCs.”

Ready to Go

TEST UNITS: Kelly A/C and Heating installed its first Trane test unit last year and, to date, has completed eight R-454B installations. (Courtesy of Trane and Kelly A/C and Heating)

Most manufacturers will start rolling out their new A2L units later this year, following close collaboration with dealers to install test equipment before it becomes widely available to the public. One of these dealers is Todd Kelly, CEO of Kelly A/C and Heating Inc. in Whitehouse, Texas. Kelly's company installed its first Trane test unit last year, and to date, has completed eight R-454B installations, each involving the replacement of an existing residential system. The installed Trane test units included a ducted 5-ton variable-speed condenser in February 2023 and a ducted 3-ton variable-speed heat pump and air handler in January 2024.

“Before we installed our first units, we referenced training from one of the suppliers on the new equipment and more closely reviewed the manual,” said Kelly. “We do this every day, but there are some changes to note. For example, the new refrigerant has different charging parameters (see above) that we have to follow, so we read them carefully to make sure we were doing it properly. We also had a Trane representative with us on the first installation.”

Handling the mildly flammable A2L refrigerant has not been a concern for Kelly or his technicians. “I am not alarmed,” he said. “There is a lot of hype about refrigerant flammability, but in reality, it's going to take a lot of refrigerant to do any damage. And there are more dangerous things out there, especially compared to early day air conditioners that used ammonia.”

Homeowners don’t seem too concerned about the new refrigerant either, said Kelly, who noted that it’s simply a matter of educating them — same as with the previous transition from R-22 to R-410A. He added that customers who have received the high-efficiency test units seem to really like them, and technicians appreciate that they are able to remotely access the equipment to make sure that they are operating correctly.

While his company is not advertising A2L equipment, as it is not currently available beyond the test units, Kelly says they’re ready to go once it hits the market, having received training and purchased the necessary tools. The only other thing he wishes he had is more room in the truck.

“Right now we carry three refrigerants on our truck, and this is our fourth,” he said. “The room in our vans is getting smaller!”

Business as Usual

Austin Branstetter, owner of Quality Heating and Air in Louisville, Kentucky, also recently had the opportunity to install an A2L test system. A long-time Carrier dealer, Branstetter had friends who worked at the nearby Midea America Research Center (MARC), and they reached out to him to see if he would be willing to install one of their new A2L units. He was more than happy to take on the residential installation, which involved an Evox G³, 3-ton, high-efficiency, R-454B, heat pump system from Midea that replaced a split-system air conditioner and gas furnace.

NEW SYSTEM: Quality Heating and Air recently had the opportunity to install a Midea Evox G³ heat pump that utilizes the A2L R-454B. (Courtesy of Midea)

PHASEDOWN UPDATE: As part of the AIM Act, EPA is mandating a 700 GWP limit for most new comfort cooling equipment starting next year. (Courtesy of Quality Heating & Sheet Metal Co. Inc.)

“There really wasn't a huge learning curve. Especially compared to when R-410A came out, and it was a big jump in pressure from R-22. The pressures of R-454B and R-32 are very similar to R-410A,” said Branstetter. “As far as the actual installation was concerned, it was business as usual. Even my guys were surprised, because they thought it was going to be very different. But it was really just the same — nothing special.”

In preparation for his first installation, Branstetter received training on A2Ls from his local trade association, Indoor Comfort Association, and he also took advantage of some of the training videos offered on YouTube by refrigerant manufacturers. With that knowledge, he was able to train his own technicians, who he noted were not nervous at all about working with the new refrigerants.

“We deal with natural gas and propane, which are much more volatile than A2Ls,” said Branstetter. “All of my guys use best practices, so it really wasn't a nerve-racking thing for us. Not at all.”

For those contractors who are nervous about the transition to A2Ls, the best they can do is educate themselves about the new refrigerants, said Branstetter.

“Education is everything, so get educated on the facts. Don’t be one of those contractors who just listens to the rumors,” he said. “In today's society, the information is literally at your fingertips. The refrigerant companies and equipment manufacturers want to educate you. They have videos out there, or you can call your manufacturer’s rep and ask how to get training.”

Numerous Installs

Daikin has had some of its A2L equipment available in the U.S. since early 2022, when it introduced ATMOSPHERA, a single-zone, ductless system that uses R-32. Kevin Pike, commercial HVAC and plumbing manager at Andgar Mechanical LLC in Ferndale, Washington, couldn’t wait to get his hands on the new equipment, opting to install the first system in his own home that same year. By the end of 2024, he estimates that his company will have installed approximately 300 Daikin Atmosphera systems.

MULTIFAMILY SOLUTION: Andgar Mechanical has found that Daikin’s R-32 Atmosphera ductless systems work particularly well in low- and mid-rise multifamily housing projects. (Courtesy of Kevin Pike)

“We're predominantly a design-build mechanical contractor, and we specialize in low- and mid-rise multifamily housing projects that are seven stories and below,” said Pike. “In Washington, if a project is three stories and below, it's considered a residential project; if it's four stories and above, it's considered a commercial project, which then falls under all the commercial mechanical codes. To comply with the new energy codes, we’re finding these split ductless systems work really well. Also, the Daikin Atmosphera systems allow for longer line lengths and vertical rise, which helps us overcome some of the construction hurdles that we sometimes face on these low- and mid-rise apartment complexes.”

In preparing to install A2L equipment, Pike and his technicians took advantage of local training that focused on best practices for installation and repair. This was nothing new for them, as the company already holds its technicians to very high standards.

“We nitrogen purge during brazing at all times, pressure test to a minimum of 600 psig to ensure leak-free systems, and use best practices in flaring and low micron level evacuation,” said Pike. “So for us to install an R-32 system was not a problem, as our processes didn’t have to change significantly. We're already holding ourselves to a high bar during installation to ensure the viability and reliability of the equipment.”

Like Branstetter, Pike found the transition from R-22 to R-410A to be more challenging than moving from R-410A to A2L refrigerants.