Quick Answer: Your mini split runs on one of three refrigerants: R-410A (the old standard, now banned from new manufacture as of January 1, 2025 per the EPA’s AIM Act rule), R-32, or R-454B (the two lower-GWP replacements now standard on nearly every new system). The refrigerant itself rarely matters for day-to-day performance — what matters is the EPA Section 608 rule: any system that requires a technician to open the refrigerant circuit (braze, vacuum, charge) legally needs a certified installer, while pre-charged quick-connect DIY kits like MRCOOL DIY sidestep that requirement entirely by never opening the line set.
Refrigerant type is one of the least-understood specs on a mini split spec sheet, and it’s easy to assume it’s a performance detail like SEER2 or noise rating. It isn’t. The refrigerant a system uses mostly decides two things that actually affect your buying decision: whether the unit qualifies as new-manufacture legal to sell, and whether you’re allowed to install it yourself without hiring a licensed technician.
The three refrigerants, compared
| Refrigerant | GWP | Safety class | Status | Common on |
|---|---|---|---|---|
| R-410A | 2,088 | A1 (nonflammable) | Banned from new manufacture since 2025-01-01; existing systems grandfathered | Pre-2025 systems, still serviceable |
| R-32 | 675 | A2L (mildly flammable) | Current, EPA-compliant | Daikin, Mitsubishi, LG, Klimaire Entrada |
| R-454B | 466 | A2L (mildly flammable) | Current, EPA-compliant | Carrier, Trane, Rheem, MRCOOL DIY 5th Gen, Klimaire Quick Connect DIY |
Both replacement refrigerants sit well under the EPA’s 700 GWP cutoff for new residential equipment, and neither is a “better” pick in the way SEER2 or a warranty term is — which one your system uses depends on which manufacturer built it, not a spec you shop for directly.
Why R-410A is disappearing
R-410A carries a GWP of 2,088, meaning a pound of it traps roughly 2,088 times more heat in the atmosphere over 100 years than a pound of CO2. The EPA’s Technology Transitions rule, issued under the 2020 AIM Act, prohibits manufacturing new residential and light-commercial AC and heat pump equipment with any refrigerant rated above 700 GWP — R-410A misses that bar by a wide margin, so new production stopped January 1, 2025. If you’re shopping in 2026, virtually every current mini split on the market is already R-32 or R-454B; you’d have to specifically hunt down old-stock or discontinued inventory to find a new-in-box R-410A unit.
That doesn’t strand anyone who already owns an R-410A system. Existing installations are grandfathered — a technician can still recover, recharge, and service R-410A equipment indefinitely under current EPA rules, and there’s no mandate to replace a working unit early just because the refrigerant inside it is being phased out for new manufacture.
R-32 vs R-454B — why it’s not really a choice
Unlike SEER2 or warranty length, refrigerant type isn’t something most buyers pick between; it’s baked into which brand and line you choose. Daikin, Mitsubishi, LG, and Goodman/Amana standardized their ductless lineups on R-32. Carrier, Trane, and Rheem went with R-454B, and on this site’s core DIY category, MRCOOL’s current 5th Gen DIY line uses R-454B while Klimaire splits its lineup — the budget Entrada tier runs R-32, while the Quick Connect DIY tier (Klimaire’s MRCOOL competitor) runs R-454B. Both refrigerants are A2L-classified — mildly flammable, a step up from R-410A’s nonflammable A1 rating — which mainly affects what tools a servicing technician needs (A2L-rated gauges, recovery equipment, leak detectors), not how a correctly installed, UL-listed system behaves sitting in your living room.
The EPA rule that decides who can install it
This is the part that actually changes a buying decision, and it has nothing to do with which of the two current refrigerants a unit uses. EPA Section 608 requires certification for anyone who opens a refrigerant circuit — brazing line-set connections, pulling a vacuum, or charging refrigerant into the system. Traditional mini splits, regardless of whether they run R-32 or R-454B, require that work, which is why a licensed HVAC technician handles the refrigerant side of a standard pro install.
Pre-charged, quick-connect systems exist specifically to route around that requirement. The line set ships factory-sealed with the exact refrigerant charge for that unit; installing it means connecting quick-connect fittings that never open the sealed circuit, so no EPA 608 certification applies to that step. That’s the entire mechanism behind MRCOOL’s DIY line and Klimaire’s Quick Connect DIY tier being legally homeowner-installable while every other brand on this site is pro-install only. It’s also why our installation cost guide shows such a wide gap between DIY equipment-only pricing and a professionally installed quote — a big chunk of that pro-install cost is paying for a federally licensed skill, not just labor time.
MRCOOL DIY 5th Gen Mini Split (R-454B, Pre-Charged)
- Factory-sealed quick-connect line set means the refrigerant circuit is never opened during install.
- Runs on R-454B (GWP 466), well under the EPA's 700 GWP cutoff for new equipment.
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What this means if you’re shopping right now
If you’re comparing new systems, you can mostly stop thinking about refrigerant type as a differentiator — nearly everything currently sold is R-32 or R-454B, both compliant, both A2L, and the performance difference between them shows up in the manufacturer’s SEER2 and low-ambient ratings, not the refrigerant name itself. The one refrigerant-related question worth asking before you buy is the EPA 608 one: does this specific model ship pre-charged with a quick-connect line set (DIY-legal), or does it need brazed connections and a vacuum pull (pro-install only, regardless of R-32 or R-454B)? Our electrical requirements guide covers the other permit-relevant part of a DIY install — breaker, wire, and disconnect code — that applies even on a fully pre-charged refrigerant system.
The bottom line
R-410A is done for new manufacture as of January 1, 2025 — if you’re buying new in 2026, you’re getting R-32 or R-454B either way, and both are EPA-compliant with GWP well under the 700 cutoff. The refrigerant name itself won’t change your day-to-day experience; what decides whether you can legally install the system yourself is whether it’s pre-charged and quick-connect (no EPA 608 needed) or requires brazing and a vacuum pull (licensed technician required, regardless of which of the two current refrigerants is inside). Ready to buy a DIY-legal system? Our best DIY mini split roundup ranks the pre-charged options by size, and if you’re weighing MRCOOL against the newer, cheaper Klimaire alternative, see our Klimaire review for the full tier breakdown.