TRANSITIONING TO LOW-GWP

ALTERNATIVES IN MVACS

Background 

This fact sheet1 provides current information on low-Global Warming 

Potential (GWP) alternatives in newly manufactured Motor Vehicle 

Air Conditioners (MVACs) relevant to the Montreal 

Protocol on Substances that Deplete the Ozone Layer.

MVACs cool passenger cars, light duty trucks, buses, 

and rail vehicles. They have been produced in the 

United States since the 1960s and in Japan since the 

1970s. MVACs were not widely used in Europe or 

developing countries until the 1990s. Charge sizes are 

0.5–1.2 kg and average lifetimes are 12–16 years.

MVACs in passenger cars, light duty trucks, buses, and 

rail vehicles account for an estimated 24% of today’s global HFC consumption. In 

the refrigeration/air conditioning (AC) sector, these MVACs account for an estimated 

30% of refrigeration/AC HFC consumption. Developing countries account for an estimated 68 million metric tons of carbon dioxide equivalent (MMTCO2

eq.) 

or 26% of global HFC consumption in these MVAC end-uses. 

2010 HFC Consumption

(Estimates Presented in MMTCO2eq.)

Refrigeration/

AC (79%)

Foams 

(11%)

Aerosols

(5%)

Fire Extinguishing

(4%)

Solvents

(1%)

Other 

Refrigeration/AC

(70%)

MVACs

Developed

Countries

(22%)

MVACs

Developing 

Countries

(8%)

Global HFC Consumption Total: 1,087 MMTCO2eq.

Global Refrigeration/AC Sector Total: 858 MMTCO2

eq.

Global HFC Consumption MVAC: 257 MMTCO2

eq.

HFC Alternatives and Market Trends 

CFC-12 refrigerant was historically used in MVACs. HFC-134a replaced R-12 in new equipment in the early 1990s. Today R-134a is the dominant refrigerant used 

in cars worldwide. In buses and trains, about 50% of global equipment uses HCFC-22 refrigerant; the remainder uses R-134a or HFC-407C (a blend of HFCs). Some 

low-GWP alternatives are summarized below.

R-152a

• Good energy efficiency and cooling performance 

• Requires additional safety requirements; other components remain the 

same as standard R-134a systems 

• To date, no vehicle manufacturer has committed to using R-152a

Carbon Dioxide (R-744) 

•

•

•

Cooling performance, energy efficiency, and fuel use comparable to 

R-134a systems in most cars

Prototype R-744 systems are in use in buses and trains in Europe; 

commercialization is expected within two years 

Verband der Automobilindustrie expressed interest in R-744 for 

passenger vehicles

HFO-1243zf3/R-32/R-134a Blend 

• 

• 

• 

• 

Flammability similar to that of R-1234yf

Energy efficiency is expected to be equal or better than R-134a 

Toxicity expected to be low

Not currently produced in high volumes

HFO-1234yf2

•

•

•

•

•

•

m

m

Cooling performance and fuel use comparable to R-134a

Potential use as a direct substitute in R-134a systems

Approved in Japan and for small volumes in Europe

Proposed as acceptable by the U.S.; final decision expected in 2010 

Production update:

 A pilot R-1234yf production facility is anticipated to be operational 

in less than two years with large-scale capacity by 2015

 A production facility in China is scheduled to begin operation in 2011

General Motors plans to manufacture some models with R-1234yf in 

model year 2013 

Europe’s Experience

The existing fleet of cars in Europe uses R-134a for AC. New 

European Union (EU) regulations require cars sold in the EU to 

use refrigerants with GWPs less than 150 beginning in 2011 for 

new vehicles and in 2017 for all vehicles. EC Directive 2006/40/

EC requires the EC to consider extending this regulation to AC in 

buses, coaches, and trucks.
Refrigerant Transition in the MVAC End-Use*

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

•

•

•

•

•

•

•

•

•

R-134a

R-134a

R-152a

R-1243zf Blend

R-1234yf

R-22 R-744

R-744

R-407C

R-12

R-12

Passenger Vehicles 

and Light Duty Trucks:

Buses and Trains:

*Solid arrows represent alternatives already available in the market for these systems; dashed arrows 

indicate those likely to be available in the future.

Refrigerant GWP ODPa

R-12 10,900 1

R-22 1,810 0.055

R-407C 1,774 0

R-134a 1,430 0

R-1243zf/R-32/R-134a Blend <150 0

R-152a 124 0

R-1234yf 4 0

R-744 (CO2

) 1 0

a

 ODP = ozone depletion potential

Challenges to Market Entry and Potential Solutions

The following table summarizes the challenges associated with the various alternatives as well as potential solutions to overcoming them.

Alternative Challenges to Market Entry Potential Solutions

R-1234yf • 

• 

• 

• 

Slight Flammability Risks

Limited Production Capacity

Regulatory Approval

Limited Availability May Prevent Full Market Penetration in

• 

• 

• 

• 

• 

the Near-Term

Safety System Installation

Engineering Design

Increase Production Capacity

Currently Under EPA’s Significant New Alternatives Policy 

(SNAP) Program Review

Currently Under EU Registration, Evaluation, Authorisation, 

and Restriction of Chemicals (REACH) Review for High Volume 

Applications

R-152a Higher Flammability Risks

Limited Production Capacity

 Safety System Installation

 Engineering Design

 Increase Production Capacity

R-744 Needs New Servicing Infrastructure

Asphyxiation Risks

High Operating Pressures

Regulatory Approval

System Reliability and Leak Reduction

 Engineering Design

 Training and Education

 Inclusion of Odorant in Formulation as a Warning System

 SNAP Proposed Use Conditions to Address Risks

R-1243zf/R-32/

R-134a Blend

Slight Flammability Risks

Not Currently Manufactured

Needs Regulatory Review and Approval

 Safety System Installation

 Engineering Design

Future Outlook

Together, the suite of known alternative chemicals, new technologies, and better process and handling practices can significantly reduce HFC consumption in 

both the near and long term, while simultaneously completing the HCFC phaseout. Although much work remains to fully adopt these chemicals, technologies, 

and practices, and some unknowns still remain, the industries currently using HCFCs and HFCs have proven through the ODS phaseout that they can move 

quickly to protect the environment.
References

Coons, Rebecca. 2010. “Honeywell, DuPont Form JV to Produce Refrigerant.” ChemicalWeek. May 24, 2010. 

European Commission (EC). 2009. “EC Policy on HFCs & Other Fluorinated Greenhouse Gases.” Presented by Thomas Verheye at the Workshop on the 

Dialogue on High-Global Warming Alternatives for ODS. Geneva, Switzerland. July 14, 2009. 

European Commission (EC). 2006. “Directive 2006/40/EC of the European Parliament and of the Council of 17 May 2006 relating to emissions from airconditioning systems in motor vehicles and amending Council Directive 70/156/EEC.” Official Journal of the European Union. L 161/12. June 14, 2006. 

European Fluorocarbons Technical Committee (EFCTC). Undated. “Fluorocarbons and Sulphur Hexafluoride.” Available online at: 

http://www.fluorocarbons.org/en/applications/air_conditioning.html. Accessed July 15, 2010.

Greenpeace. 2010. “Cool Technologies: Working Without HFCs—2010, Examples of HFC-Free Cooling Technologies in Various Industrial Sectors.” 

Presented at the 30th Open-Ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer. June 2010. 

Available online at: http://www.unep.ch/ozone/Meeting_Documents/oewg/30oewg/conf-ngos/COOLING%20%20WITHOUT%20HFCs%20-%20

2010-GREENPEACE.pdf. Accessed September 30, 2010. 

International Panel on Climate Change (IPCC). 2007. “Climate Change 2007: The Physical Science Basis.” Contribution of Working Group I to the 

Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, 

M. Tignor, and H.L. Miller (Eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. September 2007. Available online 

at: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html. Accessed September 30, 2010.

Korzeniewski, Jeremy. 2009. “HFO-1234yf: Get Used to Hearing It.” Autoblog Green. October 24,, 2009. Available online at: 

http://green.autoblog.com/2009/10/24/hfo-1234yf-get-used-to-hearing-it/. Accessed September 20, 2010. 

Mendel, Jenny. 2010. “GM to Use Climate-Friendly Refrigerant.” Greenwire. July 26, 2010. 

R744.com. 2010. “World’s First CO2 Bus A/C Cools in Berlin.” July 5, 2010. Available online at: 

http://www.r744.com/articles/2010-07-05-update-worlds-first-co2-bus-ac-cools-in-berlin.php. Accessed September 20, 2010.

Technology and Economic Assessment Panel (TEAP). 2010. “Report of the TEAP XXI/9 Task Force.” Presented by Lambert Kuijpers, Miguel Quintero, 

Dan Verdonik, and Shiqiu Zhang at the 30th Open-Ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone 

Layer. Geneva, Switzerland. June 15, 2010. Available online at: 

http://www.unep.ch/ozone/Meeting_Documents/oewg/30oewg/conf-presentations-en.shtml. Accessed September 30, 2010.

Technology and Economic Assessment Panel (TEAP). 2010. “TEAP 2010 Progress Report, Volume 1: Assessment of HCFCs and Environmentally Sound 

Alternatives, Scoping Study on Alternatives to HCFC Refrigerants under High Ambient Temperature Conditions.” May 2010. Available online at: 

http://www.unep.ch/ozone/Assessment_Panels/TEAP/Reports/TEAP_Reports/teap-2010-progress-report-volume1-May2010.pdf. Accessed September 

30, 2010.

Technology and Economic Assessment Panel (TEAP). 2009. “Task Force Decision XX/8 Report: Assessment of Alternatives to HCFCs and HFCs and 

Update of the TEAP 2005 Supplement Report Data.” May 2009. Available online at: 

http://www.unep.ch/ozone/Assessment_Panels/TEAP/Reports/TEAP_Reports/teap-may-2009-decisionXX-8-task-force-report.pdf. Accessed September 

30, 2010.

1

 The four fact sheets in this series (October 2010) cover domestic refrigeration, commercial refrigeration, motor vehicle air 

conditioning, and unitary air conditioning. These four end-uses represent about 85% of HFC consumption in the refrigeration/AC 

sector. The remaining HFC consumption in the refrigeration/AC sector comes from other end-uses including chillers, cold storage, 

industrial process refrigeration, and refrigerated transport. Any service-related consumption is attributed to the specific end-use.

2 HFOs (hydrofluoro-olefins) are unsaturated HFCs. HFO-1234yf refrigerant is also commonly referred to as 

HFC-1234yf or R-1234yf, as it is referred to in the remainder of this fact sheet.

3 HFO-1243zf is also commonly referred to as HFC-1243zf or R-1243zf.

U.S. Environmental Protection Agency

EPA-430-F-10-041 • www.epa.gov • October 2010

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