Chiller Refrigerant Types: Selection and Regulations

Chiller refrigerant selection affects compressor design, operating pressure, safety controls, efficiency, service availability and regulatory compliance. There is no universal “best” refrigerant: the correct choice depends on the chiller model, capacity, temperature range, installation location and destination-market rules.

Important: Refrigerants are not interchangeable unless the chiller manufacturer has approved a conversion procedure. Never charge an existing system with a different refrigerant solely because its pressure or capacity appears similar.

Common Chiller Refrigerants: Quick Comparison

Refrigerant	Family	ASHRAE safety class	Typical chiller context	Key selection issue
R410A	HFC blend	A1	Many existing scroll and positive-displacement chillers	High-GWP refrigerant subject to phase-down and equipment-transition rules
R407C	HFC blend	A1	Some screw/scroll chillers and engineered R22 retrofits	Significant temperature glide; retrofit requires OEM review and often lubricant work
R134a	HFC	A1	Many existing centrifugal and screw chiller platforms	High-GWP refrigerant; future equipment choices are model- and market-specific
R454B	HFO/HFC blend	A2L	Lower-GWP R410A alternative for purpose-designed new equipment	Mildly flammable; requires A2L-rated equipment and installation practices
R513A	HFO/HFC blend	A1	Lower-GWP R134a alternative in approved new or retrofit applications	Compatibility and performance must be confirmed by the equipment manufacturer
R32	HFC	A2L	Selected purpose-designed chillers and heat pumps	Not a drop-in replacement; different charge, pressure and safety requirements
R717 (ammonia)	Natural refrigerant	B2L	Industrial refrigeration and selected industrial chiller systems	Higher-toxicity classification and specialist system/safety requirements
R744 (CO2)	Natural refrigerant	A1	Specialized high-pressure and transcritical systems	Purpose-designed components, controls and service expertise required
R22	HCFC	A1	Legacy equipment	Ozone-depleting refrigerant controlled under the Montreal Protocol and national rules

ASHRAE safety classes combine toxicity (A = lower toxicity, B = higher toxicity) and flammability categories. “A1” does not mean risk-free; pressure, decomposition products, confined-space exposure and handling rules still apply.

R410A: Widely Installed, but in Transition

R410A is an A1 HFC blend used in many existing positive-displacement air-conditioning and chiller platforms. It operates at substantially higher pressure than R22 and requires equipment designed for it. Its high global-warming potential places it within HFC phase-down and technology-transition programs.

R410A remains serviceable or available in some markets and applications, but rules for new equipment vary by jurisdiction and equipment category. Do not assume that one national compliance date applies worldwide.

R407C: Zeotropic Blend and Engineered R22 Retrofit Option

R407C is an A1 blend of R32, R125 and R134a. Its temperature glide means technicians must use the correct bubble/dew pressure-temperature data for charging, superheat and subcooling.

R407C can be used in some engineered R22 conversions, but it is not a simple drop-in. Chemours retrofit guidance calls for checking OEM compatibility, lubricant, elastomers, the expansion device and warranty requirements; many conversions require changing from mineral oil to POE and replacing the filter-drier.

R134a: Established Chiller Refrigerant

R134a is an A1 HFC used in many existing centrifugal, screw and other medium-pressure chiller designs. The refrigerant alone does not determine compressor type or capacity range. Lower-GWP alternatives such as R513A or HFO refrigerants are used in some newer platforms, but suitability depends on the specific chiller design.

R454B: Lower-GWP A2L Alternative for New Equipment

R454B is an R32/R1234yf blend with an A2L safety classification. Chemours publishes a 100-year GWP of 466 using the IPCC Fourth Assessment Report basis and 467 using the Fifth Assessment Report basis, compared with 2,088/1,924 respectively for R410A.

R454B is intended for purpose-designed new equipment; it is not a field drop-in for an R410A chiller. A2L equipment may require refrigerant detection, ventilation, charge limits, labeling, ignition-source controls and service procedures according to the product standard and local code.

Read the GESON R454B refrigerant guide.

R513A: A1 Lower-GWP Alternative in Approved Applications

R513A is an azeotropic R1234yf/R134a blend with an A1 safety classification. It is listed by the US EPA SNAP program as acceptable for positive-displacement chillers, and refrigerant manufacturers publish it for selected new-equipment and retrofit uses.

“Acceptable” does not mean universally interchangeable. Compressor envelope, lubricant, seals, controls, capacity and certification must be checked against the chiller manufacturer’s approved procedure.

Read the GESON R513A guide.

R717 (Ammonia): Industrial Refrigerant with Specialist Requirements

R717 is an efficient, zero-ODP refrigerant with a B2L safety classification. It is used extensively in industrial refrigeration, especially food processing and cold storage. Performance depends on system design and operating conditions; the former blanket claim of a fixed 15–20% COP advantage is not a reliable selection rule.

Because “B” denotes higher toxicity and “2L” denotes lower flammability, ammonia installations require appropriate machinery-room design, detection, ventilation, relief discharge, emergency planning and trained personnel under the applicable code.

R744 (CO2): Specialized High-Pressure Systems

R744 has an A1 safety classification and a reference GWP of 1, but CO2 systems operate at much higher pressures than conventional HFC chillers. Transcritical performance is sensitive to ambient conditions and system architecture. Specify it only in purpose-designed equipment with qualified service support.

R22: Legacy HCFC Equipment

R22 is an ozone-depleting HCFC controlled under the Montreal Protocol. Phase-out schedules and service rules differ by country group and national law. The United States ended production and import of virgin R22 for servicing in 2020, while reclaimed material may still be used for existing equipment under applicable rules.

Do not describe R407C—or any other refrigerant—as a universal drop-in. For an R22 chiller, compare leak repair, continued service with legally available reclaimed refrigerant, an OEM-approved retrofit and equipment replacement.

How to Select a Refrigerant for a New Chiller

Confirm destination-market rules. Check the exact equipment category, capacity, compliance date and exemptions.
Use the chiller manufacturer’s approved refrigerant. Compressor, heat exchangers, expansion device, oil and controls are selected as a system.
Check safety and building-code requirements. A2L, A3 and B-class refrigerants can change charge limits, ventilation, detection and location requirements.
Compare certified performance. Evaluate full- and part-load efficiency at the required chilled-fluid and ambient/condenser-water conditions.
Plan for service. Verify trained technicians, recovery equipment, parts and refrigerant availability in the installation country.
Use a consistent GWP source. GWP values differ between IPCC assessment reports and regulatory annexes; state the basis when comparing numbers.

Current Refrigerant Regulations: Avoid One-Line Global Claims

Kigali Amendment

The Kigali Amendment phases down HFC production and consumption, not every individual refrigerant on one global date. UNEP identifies four country groupings with different baselines and step-down schedules.

United States

The EPA AIM Act Technology Transitions Program sets restrictions by sector, subsector and compliance date. A single “GWP above 700 is banned from 2025” statement is not accurate for every chiller. Check the EPA sector table and the equipment’s manufacture/import date. EPA SNAP acceptability is a separate program and may include use conditions.

European Union

Regulation (EU) 2024/573 contains chiller-specific placing-on-the-market prohibitions. Annex IV includes thresholds and dates that differ for chillers up to 12 kW and those above 12 kW, with safety exceptions. For example, the regulation lists a GWP threshold of 750 for chillers above 12 kW from 1 January 2027, subject to the legal text and applicable exceptions.

GESON Chiller Refrigerant Options and Legacy R22 Support

GESON can supply new chillers engineered for R454B or R513A. The offered refrigerant depends on the chiller model, required cooling capacity, leaving-fluid temperature, return-fluid temperature, water or glycol concentration, flow rate, ambient or condenser-water design condition, power supply, destination country, safety code and certification requirements.

New R454B chillers: available as a model-specific new-equipment selection. R454B is A2L; the chiller, controls, installation and service plan must meet the applicable product standard and local code.
New R513A chillers: available as a model-specific new-equipment selection where the required capacity, temperature range, compressor platform and destination rules are compatible.
Legacy GESON R22 equipment: spare-parts and refrigerant-related support are available subject to the equipment model and serial number, fault diagnosis, legal refrigerant availability, technician scope, destination-country rules and shipping restrictions.

These capabilities do not make R454B or R513A a drop-in replacement for another refrigerant, and they do not guarantee that every legacy R22 unit can or should be repaired. GESON will confirm the proposed refrigerant, rated conditions, actual cooling capacity, compressor type, electrical supply, materials, accessories and service scope in the written model selection or quotation.

For a selection, provide the application, required cooling capacity, inlet and outlet fluid temperatures, flow rate, carrier fluid and glycol concentration, maximum ambient temperature or condenser-water conditions, power supply and destination country.

Request Chiller Selection or R22 Service Review.

CHILLER REFRIGERANT TYPES: SELECTION AND REGULATIONS