This guide covers the basics, but if you want to be fully prepared for any breakdown, check out my comprehensive DIY HVAC Course. For a limited time, it’s just $20. Think of it this way: You can pay $500 for a one-time repair, or $20 to learn how to maintain and fix your system forever.

But for now, let's get your air blowing again. Here is your ultimate HVAC electrical troubleshooting guide.

Whether you are managing "sell-through" inventory or commissioning a brand-new A2L system, you need data, not history lessons. We have compiled the ultimate A2L refrigerant list, a quick-reference A2L refrigerant pressure chart, and the specific 2026 compliance rules for your van.

Bookmark this page. You are going to need it.

Unlike previous transitions that focused solely on saving the ozone layer, the shift we experienced in 2025 was about lowering the "Global Warming Potential" (GWP) of the gas inside your AC. New A2L refrigerant options, such as R-454B (now common in homes) and R-454A (now standard in commercial refrigeration), are chemically designed to absorb significantly less heat in the atmosphere if they leak.

You might be wondering: if the old stuff was non-flammable, why did the EPA mandate a switch to a new A2L refrigerant that has any flammability at all?

The answer is balance. To create a refrigerant that cools effectively without destroying the environment, chemists had to change the molecular structure.

• Old R-410A: Non-flammable (A1), but had a massive Global Warming Potential (GWP) of 2,088.

• New A2L (R-454B): Mildly flammable (A2L), but drops that GWP down to 466.

So, are A2L refrigerants flammable? Yes, by strict definition. Is your new AC dangerous? No.

The A2L refrigerant flammable label is there for technicians handling tanks in the back of a hot van, not for homeowners enjoying cool air. With high ignition temperatures, slow burning speeds, and advanced safety sensors, these new HFO-based systems are designed to be as safe as—if not safer than—the older units they replaced.