Refrigerant gases, metering devices & piping: this article series describes the properties of common and historic air conditioning refrigerants. We combine U.S. EPA information with supplemental data and descriptions of refrigerants, refrigerant replacement options for R12 and R22, and their basic data.
Air conditioning refrigerants and agents to transfer heat from one place to another have been in use for a long time and include Ammonia, Sulfur Dioxide, Hydrocarbons like methane, methyl chloride, and methylene chloride, and safer (inert gas) HFCs like R11 (common in older refrigerators and some air conditioners) and R22 (common in older cooling equipment.
Since the realization that HFC's contribute to greenhouse gas problems in the environment, R11 and R22 have been discontinued and are being replaced with alternatives including R-410A (GENETRON AZ-20, SUVA 410A, and Puron (R-410A)), R-134A R-407C.
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Properties of Various Air Conditioning Gases and Cooling Refrigerants
DISCLAIMER: EPA [and this website reproducing this public-domain article] seeks to promote energy efficiency and the safe use of ozone- friendly substances, and does not endorse any particular company or its products.
Safety Warnings & Other Caveats about Using Refrigerant Liquids or Gases & When Servicing Refrigeration Equipment
Watch out: any refrigerant gas and gas container, including the small refrigerant canisters sold for automotive use in charging automobile or truck air conditioners can be dangerous if not properly handled.
Liquid refrigerant can injure an eye and can also cause frostbite. You should cover refrigerant lines or connectors or valves when opening them so that if liquid refrigerant escapes it is controlled. And on at least some refrigerant containers such as the automotive maintenance canisters you'll see warnings about the need for eye protection and other protective measures.
Also some refrigerant gases form highly toxic phosgene gas if released across an open flame, so if a flame is present near where refrigerant gases are being used for service be sure there is good fresh air ventilation.
Refrigerant Gas Asphyxiation hazards: Modern refrigerant gases are heavier than air as well as being odorless and colorless. The gases themselves, such as the Freon family, are not toxic and not explosive. But because the gases are heavier than air, if you were so foolish as to release a sufficient volume of gas into an enclosed space or even a low-lying outdoor area where there is no wind or indoors no ventilation, you could become asphyxiated with little or no warning.
Do not mix refrigerant gases. Each refrigerant gas has its own unique properties. If you were to mix gases within a refrigeration system the properties of the mixture would be unpredictable, making it impossible to properly adjust and operate the equipment.
Do not arbitrarily substitute refrigerant gases by charging refrigeration equipment with a gas other than the one for which it is labeled, for the same reason as above. We discuss replacement refrigerants below.,
Background: Ban on Production and Imports of Ozone-Depleting Refrigerants
In 1987 the Montreal Protocol, an international environmental agreement, established requirements that began the worldwide phase out of ozone-depleting CFCs (chlorofluorocarbons). These requirements were later modified, leading to the phase out in 1996 of CFC production in all developed nations. In addition, a 1992 amendment to the Montreal Protocol established a schedule for the phase out of HCFCs (hydrochlorofluorocarbons). HCFCs are substantially less damaging to the ozone layer than CFCs, but still contain ozone-destroying chlorine. The Montreal Protocol as amended is carried out in the U.S. through Title VI of the Clean Air Act, which is implemented by EPA.
An HCFC known as R-22 has been the refrigerant of choice for residential heat pump and air-conditioning systems for more than four decades. Unfortunately for the environment, releases of R-22 that result from system leaks contribute to ozone depletion. In addition, the manufacture of R-22 results in a by-product that contributes significantly to global warming.
As the manufacture of R-22 is phased out over the coming years as part of the agreement to end production of HCFCs, manufacturers of residential air conditioning systems are beginning to offer equipment that uses ozone-friendly refrigerants. Many homeowners may be misinformed about how much longer R-22 will be available to service their central A/C systems and heat pumps.
This fact sheet provides information about the transition away from R-22, the future availability of R-22, and the new refrigerants that are replacing R-22. This document also assists consumers in deciding what to consider when purchasing a new A/C system or heat pump, or when having an existing system repaired.
Phase out Schedule for HCFCs used in Air Conditioning Equipment, Including R-22
Under the terms of the Montreal Protocol, the U.S. agreed to meet certain obligations by specific dates that will affect the residential heat pump and air-conditioning industry:
January 1, 2004 HCFC Refrigerant Reduction Target
In accordance with the terms of the Montreal Protocol, the amount of all HCFCs that can be produced nationwide must be reduced by 35% by 2004. In order to achieve this goal, the U.S. is ceasing production of HCFC-141b, the most ozone-damaging of this class of chemicals, on January 1, 2003. This production ban will greatly reduce nationwide use of HCFCs as a group, making it likely that the 2004 deadline will have a minimal effect on R-22 supplies.
January 1, 2010 HCFC Refrigerant Reduction Target
After 2010, chemical manufacturers may still produce R-22 to service existing equipment, but not for use in new equipment. As a result, heating, ventilation and air-conditioning (HVAC) system manufacturers will only be able to use pre-existing supplies of R-22 to produce new air conditioners and heat pumps. These existing supplies would include R-22 recovered from existing equipment and recycled.
January 1, 2020 HCFC Refrigerant Reduction Target
Use of existing refrigerant, including refrigerant that has been recovered and recycled, will be allowed beyond 2020 to service existing systems, but chemical manufacturers will no longer be able to produce R-22 to service existing air conditioners and heat pumps.
For more information about this phase out, see fact sheets about the HCFC Phase out Schedule and Frequently Asked Questions on the HCFC Phase out
What Does the R-22 Phase out Mean for Consumers?
Availability of R-22
The Clean Air Act does not allow any refrigerant to be vented into the atmosphere during installation, service, or retirement of equipment. Therefore, R-22 must be recovered and recycled (for reuse in the same system), reclaimed (reprocessed to the same purity levels as new R-22), or destroyed. After 2020, the servicing of R-22-based systems will rely on recycled refrigerants.
It is expected that reclamation and recycling will ensure that existing supplies of R-22 will last longer and be available to service a greater number of systems. As noted above, chemical manufacturers will be able to produce R-22 for use in new A/C equipment until 2010, and they can continue production of R-22 until 2020 for use in servicing that equipment. Given this schedule, the transition away from R-22 to the use of ozone-friendly refrigerants should be smooth. For the next 20 years or more, R-22 should continue to be available for all systems that require R-22 for servicing.
Cost of R-22
While consumers should be aware that prices of R-22 may increase as supplies dwindle over the next 20 or 30 years, EPA believes that consumers are not likely to be subjected to major price increases within a short time period. Although there is no guarantee that service costs of R-22 will not increase, the lengthy phase out period for R-22 means that market conditions should not be greatly affected by the volatility and resulting refrigerant price hikes that have characterized the phase out of R-12, the refrigerant used in automotive air-conditioning systems.
Guide to Using Alternatives to R-22 in Residential Air Conditioning
As R-22 is/ was gradually phased out, non-ozone-depleting alternative refrigerants are / were being introduced. Under the Clean Air Act, EPA reviews / reviewed alternatives to ozone-depleting substances like R-22 in order to evaluate their effects on human health and the environment.
EPA has reviewed several of these alternatives to R-22 and has compiled a list of substitutes that EPA has determined are acceptable.
Additional refrigerants on the list of acceptable substitutes include R-134a and R-407C. These two refrigerants are / were not yet available for residential applications in the U.S., but are commonly found in residential A/C systems and heat pumps in Europe. EPA will continue to review new non-ozone-depleting refrigerants as they are developed.
Watch out: Using an alternative refrigerant to R-22 in older air conditioners and heat pumps requires more than just using a different gas (such as Puron R410-A). Other components in the system (such as refrigerant metering devices) will usually require change or adjustment. Be sure to consult the individual air conditioner or heat pump application guidelines and installation or service manual – Air Conditioners and Heat Pumps Using Puron Refrigerant [Carrier or other manufacturer] to obtain required unit changes for specific applications and for R--22 retrofit.
Watch out: EPA Warning: Recharging Air Conditioners with Wrong Refrigerant Poses Injury and Fire Risks
FOR IMMEDIATE RELEASE July 22, 2014
Original source: U.S. EPA 7/22/2014 Email distribution
Quoting advice from Lennox Industries you will see that for their equipment the company does not recommend use of refrigerants marketed as replacements for R22:
Source: PURONR (R--410A) REFRIGERANT QUICK REFERENCE GUIDE-
R-134a Refrigerant Data, References Sources
R-410 Refrigerant Data, References, Sources
Other Replacements for R12 Refrigerants
There are replacement gases for certain of the now banned refrigerants discussed in this article. Quoting Zeller 1998 
Servicing existing A/C units
Existing units using R-22 can continue to be serviced with R-22. There is no EPA requirement to change or convert R-22 units for use with a non-ozone-depleting substitute refrigerant. In addition, the new substitute refrigerants cannot be used without making some changes to system components. As a result, service technicians who repair leaks to the system will continue to charge R-22 into the system as part of that repair.
Installing new Air Conditioning units
The transition away from ozone-depleting R-22 to systems that rely on replacement refrigerants like R-410A has required redesign of heat pump and air conditioning systems. New systems incorporate compressors and other components specifically designed for use with specific replacement refrigerants. With these significant product and production process changes, testing and training must also change. Consumers should be aware that dealers of systems that use substitute refrigerants should be schooled in installation and service techniques required for use of that substitute refrigerant.
A Common Sense Approach To Servicing Your Air Conditioning or Refrigeration System
Along with prohibiting the production of ozone-depleting refrigerants, the Clean Air Act also mandates the use of common sense in handling refrigerants. By containing and using refrigerants responsibly -- that is, by recovering, recycling, and reclaiming, and by reducing leaks -- their ozone depletion and global warming consequences are minimized.
The Clean Air Act outlines specific refrigerant containment and management practices for HVAC manufacturers, distributors, dealers and technicians. Properly installed home comfort systems rarely develop refrigerant leaks, and with proper servicing, a system using R-22, R-410A or another refrigerant will minimize its impact on the environment. While EPA does not mandate repairing or replacing small systems because of leaks, system leaks can not only harm the environment, but also result in increased maintenance costs.
One important thing a homeowner can do for the environment, regardless of the refrigerant used, is to select a reputable dealer that employs service technicians who are EPA-certified to handle refrigerants. Technicians often call this certification "Section 608 certification," referring to the part of the Clean Air Act that requires minimizing releases of ozone-depleting chemicals from HVAC equipment.
A Common Sense Approach To Purchasing New Air Conditioning Systems
Another important thing a homeowner can do for the environment is to purchase a highly energy-efficient system. Energy-efficient systems result in cost savings for the homeowner. Today's best air conditioners use much less energy to produce the same amount of cooling as air conditioners made in the mid-1970s.
Even if your air conditioner is only 10 years old, you may save significantly on your cooling energy costs by replacing it with a newer, more efficient model. Products with EPA's Energy Star(R) label can save homeowners 10% to 40% on their heating and cooling bills every year. These products are made by most major manufacturers and have the same features as standard products but also incorporate energy saving technology. Both R-22 and R-410A systems may have the Energy Star(R) label. Equipment that displays the Energy Star(R) label must have a minimum seasonal energy efficiency ratio (SEER). The higher the SEER specification, the more efficient the equipment.
You should consider energy efficiency, along with performance, reliability and cost, in making your decision. And don't forget that when purchasing a new system, you can also speed the transition away from ozone-depleting R-22 by choosing a system that uses ozone-friendly refrigerants.
Why the U.S. and other countries agreed to stop the production of CFC and HCFC refrigerants
CFCs and HCFCs deplete the ozone layer, which acts as a blanket in the stratosphere that protects us from harmful UV radiation. This radiation has been linked to skin cancer, which is now one of the fastest growing forms of cancer. In the U.S., one person dies of skin cancer every hour.
Remember that ozone is "good up high, bad nearby:" even though it protects us when it is in the stratosphere, ozone at ground level can be harmful to breathe and is a prime ingredient in smog. Many man-made sources such as tailpipe emissions from cars contribute to ground-level ozone.
Clarifications & Definitions of Refrigeration Terms: Coolant, Refrigerant, Freon and Trade Names
Reader comment: Don't Just Call All Coolants or Refrigerants "Freon"
9/24/2014 Daniel said:
I think it is important to note that we are talking about refrigerants here, not coolants, and not Freons.
Coolants don't change phase to do their job of transferring heat, the liquid coolant in your car's cooling system is a liquid and is supposed to stay a liquid.
Refrigerants do change phase, usually from a liquid to a gas and back again, but even the ice in a drink can be seen as a refrigerant since it is changing phases, from solid to liquid, to keep your drink cool.
Freons are certain refrigerants, usually CFCs (like R11, R12) and HCFCs (Like R22) made by DuPont Chemicals.
It is somewhat OK to call say R22 from any manufacturer Freon, it's the same as calling any adjustable locking pliers Vise-Grip whether or not they were made by Irwin.
What is not OK is to call refrigerants that DuPont has never called Freon by that name, for instance calling R134a a Freon is wrong, because DuPont calls it Suva.
This comment was originally posted at REFRIGERANT METERING CAPILLARY TUBES
Excellently put, Daniel. Thank you for these clarifications of refrigerant terms.
Because many readers are not familiar with proper refrigerant terminology we find that people looking for information about refrigerants search on all sorts of words that we might agree are not quite correct. "Freon" has become about as generic and mis-used as "kleenex" for "tissues". Your note is helpful to readers who want to speak accurately, while keeping the word "freon" around helps people find it. I'll copy your comments into our text on refrigerants
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Frequently Asked Questions (FAQs) about HVAC System Refrigerants
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Question: can an R-22 air conditioner or heat pump system be changed to use R-401A? What is involved?
Can an A/C system that uses R-22 be changed to use R-410a? - Anon 6/3/11
What is involved with converting from R-22 to R0417A? My unit was made in 2005. - Bill 6/5/2011
can R-22 CONVERT TO R134A MY UNIT WAS MADE IN 1999. - Jonathan 6/7/11
Changing an R-22 refrigerant-based A/C system over to use R-410a is possible but costly since quite likely you cannot simply charge the system with the new refrigerant. It may be possible to continue to use the same compressor/condenser unit and air handler, but significant parts inside each of those components, such as controls and possibly evaporator/condenser coils are going to need to be changed out.
There are "swap-in" substitute refrigerants for R-22, but as you can read above in the Lennox warning, they are not recommended by at least some manufacturers. For this reason, if the R-22 based air conditioner is old and/or if other components are not in pristine condition, you'll want to get a careful price quote that allows comparing conversion of the equipment with replacement.
Question: Where can I buy R-22 freon?
where can I purchase R 22 freon
Charles I'd consider converting the refrigeration system equipment to a R-410 -based refrigerant design, as R-22 is no longer recommended. However there are some websites offering R-22 refrigerant - though at astronomical prices for the ones I've seen. Recent reporting (in 2012) has also noted that due to cost pressures and other market factors, some manufacturers continue to sell replacement HVAC parts that operate on R-22 despite its harmful effects on the atmosphere and environment.
Question: pointing out HVAC equipment operating pressure differences between R22 & R410-a
regarding your discussions on R22 against R410a.
James, thank you for making several excellent points; we agree completely. The conversion from R22 to R410 is not trivial;
Question: cost to re-charge a central air conditioning system
How much does it cost to recharge a central air conditioning system (approximately)? - Rick 8/8/2011
Rick the cost to re-charge a central air conditioner is basically a service call charge plus extra time and materials and refrigerant - $100 to $200. U.S. IF the tech only adds refrigerant.
Watch out: Since refrigerants should not leak out of an air conditioner or heat pump, if you need to add refrigerant, a good repair would include looking for and fixing the leak. In turn, depending on where the leak occurred, and what repairs are needed, the ultimate cost could therefore be much greater.
Question: Is it true that all new appliances are mandated to have chips that operate with wireless transmitter smart meters
Is it true that all new appliances are mandated to have chips that operate with wireless transmitter smart meters (that are being forced on us) ? - Goodsite 9/29/12
Question: questions about re-charging HVACR equipment using R410-a
Is it normal for new R410a system to have oil come out with refrigerant when detaching gauges.
What can cause a system to have oil come out with refrigerant? - Tim 5/23/12
Tiny amounts, may be common; significant amounts more than enough to wet the port suggest to me something is wrong with the oil distribution & charge procedure.
In commercial and most other refrigeration systems, the refrigerant delivers lubricant oils to the compressor's moving parts. If there is a refrigerant leak, the oil carried in the liquid refrigerant may be left behind and show up as a dusty dirty oily coating in the areas near the leak point.
Question: can we change refrigerants without changing the thermostatic expansion valve?
Thermostatic expansion valves IS OKY USE 410 IN E22 O R22 - 6/16/2012
It depends. The answer is no if the new refrigerant has different operating properties, density, pressures, operating range. The answer is yes if the new refrigerant is rated as a drop-in substitute for R-22, but watch out as at least some manufacturers do not recommend that approach.
Question: my heat pump was found to be low on refrigerant and now I notice my grandson has a chronic cough - could that be from the freon leak?
My heat pump system was recently serviced and found to need low about 4 lbs of refrigerant. I noticed that my small grandchildren who live with me start having a chronic cough about a month before i had the service accomplished. Now that we had it serviced both their mom and myself have developed a cough we can't get rid of. Could this possibly be from a freon leak in my system possible releasing gas inside my home? - Manuel Ortiz 6/22/12
Manuel, the refrigerants used inside of HVAC equipment are encapsulated and besides, chemically pretty inert - freon is not likely to directly explain the cough or IAQ complaint you describe.
Question: Ice on the refrigerant equipment & piping lines, refrigerant leak can't be traced until the ice melts - which will take 3 days?
MY A/C unit was not cooling my house as much as it was a week ago. A technician examined my outside fan and basement A/C, noted ice on both units and on tubing lines. He and stated it would not be possible to determine the exact source of the leak until the ice melted, which will probably take 3 days. If my children and I stay in the house during the next 3 days is there any danger that we may inhale a carcinogenic gas or be exposed to any other health risks? Thank you! - Richard Wilson 6/25/2012
Richard, I think the tech was saying that a refrigerant leak can lower the pressure in the system and cause icing on the cooling coil as well as on the refrigerant lines. (Missing insulation can also cause line icing). 3 Days? Gee that's odd. Typically if you shut off the system, in an hour or less the ice is long gone - especially in hot weather.
Question: refrigerant leaks out of our equipment - local custodian is releasing gas to the atmosphere
I work in a school, and my air conditioning unit is broken twice a year-- fall and spring (actually it has never been fixed)! I hear that a part has been replaced, and the refrigerant leaks out sometime after it is recharged again in the fall. This refrigerant goes into a large air unit (the length of one wall of my classroom) that is INSIDE the classroom, so I have a couple of questions here: First, when our custodian recharges the unit, I see him undo the hose, and I see the gas come out into my classroom for about a minute or so-- then the custodian shuts it off. He thinks it will be safe to hold class in there twelve hours later. What do you think? I'm not sure what type of refrigerant is used, but I've been told that these air conditioners are about 20 years old, and the gas seems to be odorless and you can't see it except when it is spilling out of the hose. Second, if my a/c is leaking, my guess is that it's leaking INTO my classroom. As I said, it is all gone by the time the warm weather rolls back around in the spring. Do you have any idea if this would be a danger? I am in the class all day and am trying to conceive. I don't want anything hurting my students or myself. Please, any answers would be appreciated. - Jennifer Fischer 8/16/2012
The hazards from freon-type refrigerants are not as poisons but as replacements for oxygen if they are released at high concentrations in an enclosed space.
But it is illegal and a bad practice to just dump refrigerants into the atmosphere at any time.
Questions & answers or comments about air conditioning, heat pump & refrigeration equipment gases, refrigerant metering devices, capillary tubes, TE valves, and refrigerant leak detection.
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