R290 RefrigerantRefrigerant-grade propane · Natural refrigerant · A3
R290 is refrigerant-grade propane, a single-component hydrocarbon refrigerant with zero ozone-depletion potential and very low global warming impact. It is used in equipment specifically engineered for an A3 flammable refrigerant, including domestic and commercial refrigeration and selected heat-pump systems.
What is R290 refrigerant?
R290 is propane manufactured and controlled to refrigerant specifications. Its low GWP and strong thermodynamic performance make it attractive for many applications, but its A3 classification means flammability, charge size, ignition sources, ventilation and service practice are central design constraints.
R290 refrigerant properties
These values are screening and reference data. Refrigerant-property values can vary slightly by equation of state, assessment report, supplier dataset and regulatory basis. Use the source required by the applicable equipment standard or regulation.
| Property | Reference | Engineering / source note |
|---|---|---|
| Designation | R290 | Refrigerant-grade propane |
| Chemical name | Propane | Single-component hydrocarbon |
| Formula | C₃H₈ | Pure compound |
| CAS number | 74-98-6 | NIST Chemistry WebBook |
| Molecular weight | 44.0956 g/mol | NIST Chemistry WebBook |
| Normal boiling point | Approx. −42.1°C | NIST / standard reference |
| Critical temperature | Approx. 96.7°C | Thermophysical reference |
| Critical pressure | Approx. 42.5 bar | Thermophysical reference |
| ODP | 0 | No ozone depletion |
| 100-year GWP | About 3 | EPA SNAP reference |
| Safety classification | A3 | Higher flammability |
Scientific assessment reports periodically update climate metrics, while regulations may continue using a fixed reference value. This page identifies the regulatory or technical basis for the value shown instead of presenting one number as universal.
R290 is refrigerant-grade propane — not generic fuel propane
The chemical molecule is propane, but refrigeration systems rely on controlled purity, moisture, sulfur and contaminant levels. Fuel-grade LPG or an unknown propane cylinder should not be treated as equivalent to refrigerant-grade R290.
Because R290 is a pure compound, there is no blend fractionation. The engineering challenge is instead its A3 flammability: charge limits, sealed electrical components, ignition-source management, ventilation, leak mitigation and technician procedures must be designed around the actual equipment and applicable standard.
Refrigerant choice affects pressure, compressor operation, lubricant, controls, charge, safety classification, component approval and regulatory compliance. Only use a refrigerant in equipment and conversion procedures explicitly approved for it.
Where is R290 used?
Applications depend on equipment design, refrigerant charge, climate, capacity, location and local rules. The examples below describe established or emerging use contexts, not blanket authorization for every system.
Domestic refrigeration
Household refrigerators and freezers designed for small hydrocarbon charges.
Self-contained commercial refrigeration
Display cabinets, beverage coolers and food-service equipment designed for R290.
Heat pumps & water heaters
Growing use in equipment specifically engineered for A3 refrigerants.
Selected room AC / packaged systems
Permitted only where the equipment type, charge and jurisdiction allow R290.
For broader research routes, explore the Refrigerant Database, Refrigerant Replacements and Low-GWP Refrigerants guides.
R290 vs R32
Direct comparisons are useful only when the application, system architecture and regulatory basis are defined. The table highlights major differences rather than implying interchangeability.
| Characteristic | R290 | R32 |
|---|---|---|
| Refrigerant family | R290: hydrocarbon / natural | R32: HFC |
| Type | Single-component propane | Single-component difluoromethane |
| GWP | About 3 | 675 EPA reference |
| Safety class | A3 | A2L |
| Flammability | Higher flammability | Lower flammability |
| Typical design emphasis | Strict charge/ignition control | A2L mitigation and HVAC platform design |
| Interchangeability | Dedicated R290 equipment | Dedicated R32 equipment |
Why R290’s A3 classification changes system design
R290 is A3: lower toxicity group and higher flammability. Fire and explosion prevention is therefore a primary design objective. A small refrigerant charge can reduce risk, but it does not eliminate the possibility that a release into a small enclosure, cabinet or poorly ventilated area could form a flammable mixture.
Ignition control
Relays, motors, heaters, static discharge and hot work must be evaluated.
Charge management
Allowable charge depends on equipment standard, room conditions and jurisdiction.
Service tools
Recovery, vacuum, leak-testing and repair procedures must be suitable for hydrocarbons.
Actual risk depends on refrigerant charge, release rate, room volume, ventilation, ignition sources, pressure, occupancy, equipment construction, alarm/mitigation logic, service procedure and applicable codes.
See the site-wide Refrigerant Safety Guide for an overview of A1, A2L, A3 and B2L classifications.
R290 refrigerant leak detection
Define the monitoring function first
R290 monitoring for fire risk should use hydrocarbon-compatible technology such as catalytic, infrared or validated semiconductor sensing, depending on the required range and certification. A detector calibrated only for methane should not automatically be assumed accurate for propane. Portable leak localization and fixed %LEL monitoring are different tasks.
Regulatory position of R290 in 2026
United States
EPA SNAP permits R290 in specified refrigeration and air-conditioning end uses subject to use conditions. For example, it is listed for new household refrigerators/freezers and certain self-contained room-air-conditioning applications with detailed conditions. It is not a universal substitute for every U.S. HVAC category.
European Union
EU F-gas restrictions increasingly favor non-fluorinated refrigerants in several product categories. R290’s climate profile can fit that direction, but flammability safety standards, charge limits and national implementation remain decisive.
Always verify the exact equipment category, manufacture/import date, installation date, charge size, safety standard and jurisdiction before making a compliance decision.
Is R290 being phased out?
R290 itself is not an HFC subject to the Kigali HFC phasedown. Its growth is driven by low direct climate impact, but deployment is constrained by A3 safety requirements and application-specific rules rather than GWP alone.
Use the Refrigerant Regulations Hub for country- and region-level research.
What should be compared with R290?
There is no universal “best” refrigerant. Compare options by system architecture, safety class, GWP basis, expected efficiency, charge, climate, supply chain, serviceability and regulatory lifetime.
R32
A2L HFC used broadly in air conditioning and heat pumps.
R744
Nonflammable CO₂ refrigerant with high operating pressure.
R454B
Lower-GWP A2L blend for R410A-class HVAC platforms.
Use the Refrigerant Tools hub for additional screening and calculation routes.
R290 refrigerant FAQ
What is R290 refrigerant?
What is the GWP of R290?
Is R290 flammable?
Is R290 the same as LPG propane?
Where is R290 used?
Can R290 replace R134a or R404A directly?
What sensor detects an R290 leak?
Is R290 allowed in motor-vehicle air conditioning in the U.S.?
R290 sources and further reading
The page was built from primary regulatory, standards, scientific and manufacturer technical references. Re-check the latest source before equipment design, service or compliance decisions.
Working with R290 or another refrigerant?
Use Refrigerants.net to compare refrigerants, understand safety classifications and research the current transition path for your application.
Technical Notice: This page is for refrigerant research and general technical reference. Refrigerant suitability, permitted charge, equipment approval, leak mitigation, servicing procedures and regulatory compliance depend on the specific equipment, installation and jurisdiction. Always verify current manufacturer documentation, applicable standards, SDS and local regulations before selecting, replacing, charging or servicing a refrigerant.