Refrigerants are substances used in refrigeration systems to absorb heat from one area and release it in another. Contrary to popular belief, your AC system isn’t actually cooling the air inside your home — it’s simply moving heat from indoors to outdoors, using refrigerant. Although the term “Freon” is often meant to be used interchangeably with “refrigerant,” Freon identifies a specific brand name of a few refrigerant types.

Refrigerant Characteristics

Refrigerants have desirable properties for heat transfer:

  • High latent heat to absorb substantial amounts of heat per unit of refrigerant
  • High liquid density to house more cooling capacity in a compact container
  • Low boiling point to absorb heat and undergo phase change even at low temperatures
  • Low specific heat and high latent heat to maximize heat transfer
  • Low viscosity to flow smoothly through system components
  • Nonflammable and nontoxic for safe operation

In a refrigeration cycle, refrigerant undergoes phase changes:

  • The compressor converts the refrigerant from a low-pressure gas into a high-pressure gas, increases its temperature, and pumps it through the system.
  • The condenser removes heat and changes the refrigerant from a gas to a liquid as it passes through.
  • Before entering the evaporator, the refrigerant passes through an expansion device, which slows and regulates the flow.
  • Inside the evaporator, the refrigerant changes from liquid to gas as it absorbs heat, and moisture is removed from the indoor air.
  • After leaving the evaporator, the refrigerant returns to the compressor, and the cycle repeats.

This cycle continuously moves heat from the HVAC system’s evaporator to the condenser coil, providing a cooling effect.

As we’ll describe below, modern refrigerants fall into categories based on composition.

CFC Refrigerants

CFCs (chlorofluorocarbons) contain chlorine, fluorine, and carbon. They were used widely in cooling systems until they were discovered to damage the ozone layer. As a result, under the Montreal Protocol, CFCs like R-11 and R-12 were phased out.

HCFC Refrigerants

HCFCs (hydrochlorofluorocarbons) have hydrogen, chlorine, fluorine, and carbon. As transitional CFC replacements, they’re also being phased out for depleting ozone. HCFCs include R-22 and R-123.

HFC Refrigerants

HFCs (hydrofluorocarbons) contain only hydrogen, fluorine, and carbon. Designed to replace CFCs and HCFCs, HFCs like R-134a and R-410A are being phased out due to their global warming potential.

Natural Refrigerants

Natural refrigerants such as ammonia, carbon dioxide, hydrocarbons, air, and water have no ozone impact and very low global warming potential. However, toxicity and flammability limit applications for some of them.


The choice of refrigerant depends on the system and regulatory status:

  • CFCs were once common but are now prohibited substances.
  • HCFCs are still used in some existing air conditioners and chillers but are being phased out.
  • HFCs are widely used in applications such as air conditioning, refrigeration, and foam blowing but are being phased out.
  • Toxic ammonia is common in industrial systems but not in consumer applications.
  • Carbon dioxide sees increasing use in supermarkets, vending machines, and water coolers.
  • Hydrocarbon refrigerants have specialty applications limited by flammability.

Refrigerant Identification

The ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) refrigerant numbering system is the standardized method of identifying the various chemical refrigerants. Proper refrigerant identification using this system is critical for system operation and safety. While refrigerant cylinders may use color codes, these are unreliable identifiers. Instead, verify the refrigerant number, like R-22 or R-134a, before servicing a system.

Refrigerant Safety

Proper handling of refrigerants requires using protective equipment like goggles, gloves, and closed-toe shoes, applying refrigerants only in designated systems to avoid equipment damage, and never mixing refrigerants, which can alter system pressures. HVAC technicians must practice industry and safety guidelines when recovering and recycling used refrigerant instead of venting it. They must also only attempt HVAC system service or repairs involving CFCs or HCFCs with proper training and certification. 

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Refrigerant Regulations

Environmental regulations restrict certain refrigerants because their release harms the ozone layer and increases greenhouse gas emissions. The Montreal Protocol phases out ozone-depleting CFCs and HCFCs, and the Kigali Amendment phases down high global warming HFCs. U.S. regulations govern refrigerant handling and reclamation. Building codes increasingly limit particular refrigerant uses.

Compliance is mandatory, and improper use may result in substantial fines. Always check regulations before servicing cooling systems.

Refrigerant Cost

Refrigerant prices vary by type and regulatory status. CFCs are unavailable in the United States after being phased out. R-22 and other HCFCs are increasing in price as supplies decline. HFCs are still widely accessible, but costs may rise under phase-outs. Natural refrigerants like carbon dioxide and ammonia are relatively inexpensive.

While the initial cost is a consideration, proper refrigerant selection depends on system compatibility and regulations — illegal or improper refrigerants risk equipment damage. Professional reclamation services allow the reuse of recovered refrigerant.

So, is Refrigerant Bad?

Refrigerants are essential in cooling systems but can harm the environment. CFCs and HCFCs deplete the ozone layer and are banned or being phased out. HFCs have a high global warming potential and are also being phased out. Releasing instead of recovering refrigerant increases harmful emissions.

The solution is to use approved refrigerants responsibly, recover and recycle them, and continue transitioning to alternatives like natural refrigerants, allowing society to enjoy refrigeration while reducing environmental impact.


What are today's most common refrigerants?

Common for air conditioning are R-134a for lighter cooling applications and R-410A.

How often should refrigerant be replaced?

Refrigerant doesn’t need replacement if the system has no leaks. However, leaks will require repair and refrigerant recharge.

Can I mix refrigerant types?

Never mix refrigerants — doing so alters system pressures and reduces performance.

Is venting refrigerant safe?

No. Releasing most refrigerants is illegal and causes environmental harm. Always recover and recycle properly.

How do I identify the refrigerant in my system?

Check for the refrigerant number, not unreliable color codes, to identify it positively.

Editorial Contributors
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Alora Bopray

Staff Writer

Alora Bopray is a digital content producer for the home warranty, HVAC, and plumbing categories at Today's Homeowner. She earned her bachelor's degree in psychology from the University of St. Scholastica and her master's degree from the University of Denver. Before becoming a writer for Today's Homeowner, Alora wrote as a freelance writer for dozens of home improvement clients and informed homeowners about the solar industry as a writer for EcoWatch. When she's not writing, Alora can be found planning her next DIY home improvement project or plotting her next novel.

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Lee Ann Merrill

Chicago-based Lee Ann Merrill has decades of experience writing and editing across a wide range of technical and scientific subjects. Her love of DIY, gardening, and making led her to the realm of creating and honing quality content for homeowners. When she's not working on her craft, you can find her exploring her city by bike and plotting international adventures.

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