Low-GWP Refrigerants: R32, R454B, R290, R744 & Next-Generation Options
Low-GWP refrigerants are refrigerants with lower 100-year global warming potential than many legacy HFCs such as R410A, R404A and R134a. They include A2L HFC/HFO blends, HFO refrigerants, natural refrigerants and selected lower-GWP A1 or B1 refrigerants used in specialist systems.
There is no single global definition of “low GWP”
Different regulations use different thresholds for different technologies. A 700 threshold may be relevant in one U.S. equipment category, while 150 appears in multiple EU restrictions. In other contexts, a refrigerant with GWP below 10 may be described as very low GWP.
What does “low GWP” actually mean?
“Low GWP” is a relative and regulatory-context term rather than one universal global threshold. The number becomes meaningful only when you connect it to the refrigerant, equipment category, regulation and project objective.
Example U.S. HVAC threshold
EPA's current Technology Transitions sector table uses a 700-GWP limit for relevant stationary residential and light-commercial AC / heat-pump categories.
Important EU threshold
Regulation (EU) 2024/573 uses 150 as an important threshold in multiple refrigeration, AC and heat-pump categories — but not everywhere.
Useful “very low GWP” descriptor
R290, R744, R717, R600a, R1234yf, R1234ze(E) and R1233zd(E) are examples with single-digit or near-single-digit GWP values.
GWP is not total climate impact
Direct refrigerant emissions and indirect energy-related emissions are different parts of total system climate performance.
Legacy higher-GWP refrigerants vs lower-GWP routes
These examples illustrate how the market can transition away from higher-GWP refrigerants. They are not one-to-one retrofit recommendations.
| Legacy / Higher-GWP Refrigerant | GWP | Lower-GWP Transition Examples | Typical Context | Interpretation |
|---|---|---|---|---|
| R404A | 3,922 | R455A, R744, other application-specific refrigeration routes | Commercial / industrial refrigeration | Transition, not automatic retrofit |
| R410A | 2,088 | R32, R454B, R452B, R290/R744 platform routes | AC and heat pumps | Usually new-equipment platform selection |
| R134a | 1,430 | R1234yf, R1234ze(E), R513A and application-specific options | Automotive / chillers / selected refrigeration | Route depends strongly on end use |
| R407C | 1,774 | R32 or other lower-GWP new-equipment routes | Comfort HVAC / specialist systems | Not a universal one-for-one replacement |
| R507A | 3,985 | R744 and lower-GWP refrigeration platforms | Commercial / industrial refrigeration | System architecture matters |
Low-GWP refrigerants come from several different technical routes
The lower-GWP transition is not one refrigerant family. A2L blends, natural refrigerants, lower-GWP A1 options and HFO/HCFO chemistry each occupy different application niches.
A2L Refrigerants
Lower-flammability refrigerants increasingly used in new HVAC/R equipment. Safety classification and equipment approval remain separate questions.
- R32 — 675
- R454B — 465
- R454C / R455A — 146
- R1234yf / R1234ze(E) — 1
Natural Refrigerants
Very-low-GWP working fluids including hydrocarbons, CO₂ and ammonia. They span A1, A3 and B2L safety groups and distinct system architectures.
- R290 — 3.3
- R600a — 1
- R744 — 1
- R717 — 1
Lower-GWP A1 Refrigerants
Low-GWP does not automatically mean flammable. Several A1 refrigerants and blends remain relevant in chillers and specialist refrigeration systems.
- R450A — 601
- R513A — 630
- R515B — 287
- R471A — 144
- R1233zd(E) — 4
HFO / HFO-Based Routes
HFO chemistry appears both as single-component refrigerants and in blends. It does not correspond to one safety class or one application.
- R1234yf — HFO / A2L
- R1234ze(E) — HFO / A2L
- R1233zd(E) — HCFO / A1
- R454B / R454C / R455A — HFO/HFC blends
Low-GWP refrigerant comparison table
This table highlights representative refrigerants across HVAC/R. GWP values use the EPA Technology Transitions reference basis where available.
| Refrigerant | GWP | Safety | Family | Typical Role | Transition Context |
|---|---|---|---|---|---|
| R32 | 675 | A2L | HFC | AC / Heat Pumps | Established lower-GWP HVAC route |
| R454B | 465 | A2L | HFO/HFC | HVAC / Heat Pumps | Major new-equipment route |
| R452B | 698 | A2L | HFO/HFC | Selected HVAC | Sub-700 application-specific route |
| R454C | 146 | A2L | HFO/HFC | Refrigeration / specialist | Very-low-GWP blend route |
| R455A | 146 | A2L | HFO/HFC | Refrigeration | Lower-GWP refrigeration route |
| R1234yf | 1 | A2L | HFO | Automotive AC | Very-low-GWP mobile AC route |
| R1234ze(E) | 1 | A2L | HFO | Chillers / specialist | Very-low-GWP chiller route |
| R1233zd(E) | 4 | A1 | HCFO | Chillers | Very-low-GWP A1 specialist route |
| R513A | 630 | A1 | HFO/HFC | Chillers / selected refrigeration | Lower-GWP A1 option |
| R515B | 287 | A1 | HFO/HFC | Chillers | Lower-GWP A1 chiller route |
| R471A | 144 | A1 | Blend | Specialist systems | Sub-150 A1 route |
| R290 | 3.3 | A3 | Hydrocarbon | Heat Pumps / Refrigeration | Natural-refrigerant platform |
| R600a | 1 | A3 | Hydrocarbon | Domestic Refrigeration | Small-charge natural route |
| R744 | 1 | A1 | CO₂ | Refrigeration / Heat Pumps | High-pressure natural platform |
| R717 | 1 | B2L | Ammonia | Industrial Refrigeration | Industrial natural platform |
Low-GWP refrigerants by HVAC/R application
The correct low-GWP route changes by equipment architecture. The examples below are market/application guidance, not approval lists.
Residential Air Conditioning
New comfort-cooling equipment increasingly uses lower-GWP A2L platforms.
R32 · R454B · R452BHeat Pumps
Routes span A2L, hydrocarbon, CO₂ and industrial ammonia platforms.
R32 · R454B · R290 · R744 · R717 industrialCommercial Refrigeration
Natural and low-GWP blend routes vary by charge size and system architecture.
R290 · R744 · R455A · R454C · application-specific A1Domestic Refrigeration
Household refrigerators and freezers commonly use small-charge hydrocarbon systems.
R600aAutomotive AC
Very-low-GWP HFO is now an important mobile air-conditioning route.
R1234yfChillers
Chillers use several A1, A2L and B1 lower-GWP refrigerants depending on architecture.
R1234ze(E) · R1233zd(E) · R513A · R515B · R514A (B1)Industrial Refrigeration
Natural refrigerants remain important in large industrial cooling systems.
R717 · R744Specialist Systems
Capacity, temperature and regulatory context can make other low-GWP blends relevant.
R471A · R514A · other application-specific optionsLow GWP vs safety class and energy efficiency
GWP is only one dimension. Safety classification and energy performance answer different questions.
GWP and safety class describe different properties
A refrigerant can have very low GWP and still be A3, B2L or A1. Safety class should be read independently from climate metrics.
Lower GWP does not automatically mean higher or lower efficiency
Energy efficiency depends on the complete refrigeration cycle and equipment design, not on the GWP number by itself.
A low-GWP refrigerant is not automatically a retrofit refrigerant
Existing systems and new projects require different decision paths. This distinction prevents many of the most common refrigerant-selection errors.
Existing System
Do not assume a lower-GWP refrigerant can simply replace the original charge in existing equipment.
- Check whether the OEM provides an approved retrofit path.
- Confirm pressure, capacity, controls and component compatibility.
- Check whether the safety classification changes.
- Verify refrigerant/material compatibility and service documentation.
- Confirm end-use and jurisdictional acceptability.
New Equipment
A new project can evaluate the refrigerant platform together with the equipment architecture from the start.
- Start with the application and operating temperature range.
- Identify allowed safety classes and site constraints.
- Apply GWP or regulatory targets relevant to the market.
- Compare equipment architecture and available OEM platforms.
- Confirm final refrigerant and regulatory approval together.
How U.S. and EU rules shape low-GWP refrigerant selection
Both markets are moving toward lower climate impact, but the legal mechanisms and thresholds differ by equipment category and end use.
United States
EPA's Technology Transitions Program and SNAP answer different questions. Keeping them separate is essential for accurate refrigerant research.
European Union
Regulation (EU) 2024/573 progressively tightens fluorinated-gas rules by equipment category, capacity, date and GWP.
Choose a low-GWP refrigerant by system requirements, not by GWP ranking
The lowest GWP number is not automatically the correct refrigerant. A practical selection flow starts with the system itself.
Screen, compare and calculate low-GWP refrigerant options
Use the tools to structure research, then verify the final choice against equipment documentation, safety requirements and current regulations.
Refrigerant Finder
Screen refrigerants by application, project type, GWP and safety context.
Open Finder →Refrigerant Comparison
Compare GWP, safety class, family and application role side by side.
Compare Refrigerants →GWP Calculator
Look up refrigerant GWP and compare climate-metric reductions between routes.
Calculate GWP →CO₂e Calculator
Estimate direct refrigerant CO₂-equivalent emissions from refrigerant mass or leakage.
Calculate CO₂e →Pressure-Temperature Chart
Review saturation pressure-temperature behavior for supported refrigerants.
Open P-T Chart →Low-GWP refrigerant questions
Direct answers to the most common questions about GWP thresholds, safety, applications, replacements and regulation.
What is a low-GWP refrigerant?
A low-GWP refrigerant has lower 100-year global warming potential than many legacy refrigerants used for the same broad market role. There is no single global threshold.
What GWP is considered low?
It depends on context. Regulations use different thresholds such as 700, 750 or 150 depending on equipment category, market and date.
Which refrigerants have the lowest GWP?
Examples include R744, R717, R600a, R1234yf and R1234ze(E) at GWP 1, plus R290 at 3.3 and R1233zd(E) at 4.
Is R32 a low-GWP refrigerant?
R32 has GWP 675, substantially below R410A at 2,088. Whether that counts as “low enough” depends on the regulation and application.
Is R454B low GWP?
R454B has GWP 465. It is an important lower-GWP A2L route for new HVAC and heat-pump equipment.
Is R290 low GWP?
Yes, R290 has GWP 3.3. It is an A3 hydrocarbon used in purpose-designed equipment.
Is R744 low GWP?
Yes, R744 has GWP 1. Its A1 classification does not remove the need for high-pressure CO₂ system design.
Are all low-GWP refrigerants flammable?
No. Low-GWP options span A1, A2L, A3, B1 and B2L safety groups.
What low-GWP refrigerant replaces R410A?
There is no universal replacement. New-equipment routes include R32, R454B, R452B and selected natural-refrigerant platforms depending on the system.
What low-GWP refrigerant replaces R404A?
The answer is application-specific. R455A, R744 and other refrigeration platforms may be relevant depending on equipment, temperature and market.
Which low-GWP refrigerants are used in heat pumps?
Examples include R32, R454B, R290 and R744, with R717 relevant in industrial heat pumps.
Does lower GWP mean higher efficiency?
No. Energy efficiency depends on the full refrigeration cycle, components, controls and operating conditions.
Can a low-GWP refrigerant be retrofitted into existing equipment?
Only where an approved retrofit path exists. Low GWP alone does not establish compatibility or legal acceptability.
Are low-GWP refrigerants required by law?
Many regulations restrict higher-GWP refrigerants in specific sectors, but requirements vary by equipment, jurisdiction and date. There is no single worldwide “low-GWP refrigerant law.”
Authoritative sources behind this guide
GWP values and time-sensitive regulatory statements should be checked against current official sources for the exact equipment category and market.
Primary GWP reference basis used for refrigerants and legacy comparison values on this page.
Open GWP Table →Current sector/subsector GWP restrictions, including residential/light-commercial AC and heat-pump context.
Open Sector Table →End-use-specific substitute acceptability and use conditions, separate from Technology Transitions GWP thresholds.
Open SNAP Resources →Current F-gas regulation with staged equipment restrictions by category, GWP, capacity and date.
Open EUR-Lex →Start with the system — then compare the refrigerant options
Use the database, application guides and tools to narrow the field, then confirm the final refrigerant route against equipment documentation, safety requirements and current market regulations.