The Everyday Guide to Refrigerants (and Where the Industry’s Going)
If you’ve ever glanced at an HVAC sticker and wondered what R410A or R454B means, this is for you. Below is a plain-English tour of the common refrigerants in homes, cars, and commercial systems—what they’re used for, their pros/cons, and why the market is shifting.
We’ll also hit the basics (what a refrigerant is, why oils matter, what “A2L” means, etc.) so you can make sense of quotes and recommendations.
Quick primer: what refrigerants do (and a few terms)
Refrigerant is the working fluid that shuttles heat. It boils (evaporates) at low temperature to absorb heat indoors, then condenses outdoors to reject it.
Single vs. blend: Some are single chemicals (e.g., R32, R134a); others are blends (e.g., R410A, R407C, R404A, R454B). Blends can have slight “glide” (temperature change during phase change).
Liquid / vapor / saturated: In the coil you often have a mix—saturated liquid+vapor—right where heat exchange is strongest.
Safety classes (ASHRAE 34):
A1 = lower toxicity, no flame propagation
A2L = lower toxicity, mildly flammable (the “L” means lower burning velocity)
A3 = lower toxicity, highly flammable (e.g., propane/R290)
B groups = higher toxicity (e.g., ammonia/R717). ASHRAE+1
Why so many changes lately?
Two big drivers:
Ozone protection: Old CFC/HCFC refrigerants (like R12, R22) were phased out because they damage the ozone layer. In the U.S., production/import of R22 ended Jan 1, 2020 (existing systems can still be serviced with reclaimed gas). EPA+1
Climate impact: Many newer HFCs (like R410A, R134a) don’t harm ozone but have high GWP (global warming potential). Under the AIM Act, the U.S. is phasing down HFCs 85% by 2036, pushing industry to lower-GWP options (A2L/HFOs or “natural” refrigerants like CO₂, ammonia, propane). EPA+1
The lineup (what’s what—pros, cons, where used)
R22 (HCFC, legacy)
Where: Older residential/light commercial AC.
Status: Phased out of production/import in 2020; service only with reclaimed stock.
Pros: Familiar, good performance.
Cons: Ozone-depleting; dwindling supply means rising service cost/retrofit pressure. EPA
R410A (HFC blend, A1)
Where: Most U.S. residential AC/heat pumps from ~2010s to now.
Pros: Strong performance, widely supported.
Cons: High GWP → being replaced by lower-GWP A2Ls (e.g., R454B, R32) under the HFC phasedown. EPA
R454B (HFO/HFC blend, A2L)
Where: Next-gen replacement for R410A in many new residential/light commercial systems.
Pros: Much lower GWP (~466), similar performance to R410A; OEMs are moving here.
Cons: Mildly flammable (A2L) → new handling, codes, and tools. Zero HVACR
R32 (HFC, A2L)
Where: Common globally; growing in mini-splits and packaged systems.
Pros: Good efficiency, GWP ~675 (much lower than R410A).
Cons: Mild flammability requires updated codes and training. Trane
R407C (HFC blend, A1)
Where: Retrofit option for some R22 systems and in some packaged units.
Pros: Non-ozone depleting, “drop-in” for certain applications.
Cons: Has glide; not as efficient as newer A2Ls.
R134a (HFC, A1)
Where: Older auto A/C, some chillers.
Status: Being replaced in new cars by R1234yf due to GWP.
Pros: Well-understood, stable.
Cons: High GWP; automotive sector moved on. EPA
R1234yf (HFO, A2L)
Where: New automotive A/C (cars/light trucks).
Pros: Very low GWP (~1); designed to replace R134a in vehicles.
Cons: Mildly flammable; specific oils (PAG variants) and service procedures. EPA+1
R404A (HFC blend, A1)
Where: Supermarket/freezer systems (legacy).
Pros: Strong low-temp capacity.
Cons: Very high GWP; many grocers are shifting to CO₂ (R744) or low-GWP blends.
Carbon Dioxide (CO₂, R744, A1)
Where: Supermarkets, cold storage; some heat pumps abroad.
Pros: GWP = 1, non-flammable, excellent heat transfer.
Cons: Very high operating pressure; specialized equipment/know-how. (Note: CO₂ is R744; R747 refers to “air,” not CO₂.) ASHRAE+1
Ammonia (R717, B2L)
Where: Industrial refrigeration (food plants, ice rinks, cold warehouses).
Pros: Outstanding efficiency, GWP ~0.
Cons: Toxic and mildly flammable → used in industrial settings with trained personnel and safety systems. Gas2Go
Propane (R290, A3)
Where: Small stand-alone coolers/freezers; growing in heat pumps overseas; limited in U.S. by charge limits (increasing in some equipment types).
Pros: Ultra-low GWP, excellent thermodynamics.
Cons: Highly flammable; charge size and code rules are critical. Copeland
CFCs (e.g., R12) & the phaseout story
R12 and other CFCs were great performers but ozone-depleting and were phased out years ago; now museum pieces except in specialty legacy systems. (R12 → replaced by R134a in autos; then R1234yf). EPA
“A2L” and “A3” — do I need to worry?
The move from A1 to A2L (mildly flammable) in homes is driven by the HFC phasedown. It comes with new codes, training, sensors, and installation standards—the point is to maintain safety while cutting climate impact. A3 (propane/R290) is used today mostly in small, sealed systems; larger uses depend on charge limits and evolving codes. Trane+1
Oils and compatibility (why your tech cares)
Refrigerant and compressor oil must mix correctly so oil returns to the compressor.
Mineral oil worked with many CFC/HCFC refrigerants (R12, R22).
HFCs (R134a, R410A) don’t mix well with mineral oil; they use POE (polyolester) oil.
Automotive systems use PAG oils; R1234yf needs the correct PAG formulation (not all PAGs are interchangeable).
Using the wrong oil can cause poor lubrication and failures. HVAC School+1
Costs: why your quote may look different this year
Refrigerant prices fluctuate with supply rules, allowances, and demand. As the AIM Act reduces overall HFC supply, high-GWP gases generally get tighter (and pricier), nudging the market toward lower-GWP options and reclamation. EPA
The good, the bad, and the “why” behind the shift
The good: Lower climate impact, newer equipment often brings better comfort (variable speed, smarter controls).
The bad: Transition costs—tools, training, and sometimes higher equipment prices up front.
The why: Regulatory phasedown plus real efficiency gains—especially when the whole system (ducts, airflow, sizing) is done right. EPA.
Residential vs. commercial (where things stand)
Residential/light commercial: R410A is giving way to R454B or R32 as states adopt A2L codes; installers are updating practices accordingly. Zero HVACR
Commercial refrigeration: Big growth in CO₂ (R744) and propane (R290) for cases and racks, driven by GWP goals and evolving standards. Emerson+1.
Bottom line: how Caledonian Mechanical helps you choose
We start with design: Load calculations, duct/airflow checks—because a 20-SEER unit won’t deliver 20-SEER bills through undersized or leaky ducts.
We spec the right refrigerant/equipment combo: Lower GWP where it makes sense, and only within the current code and manufacturer requirements.
We service what you have: Whether it’s R410A, an older R22 system (with reclaimed supply), or a modern A2L unit—we’ll lay out options and costs clearly. EPA