home air conditioner freon leak

It’s the hottest day of the year, and your air conditioner is struggling to cool your home. Could a Freon leak be the culprit? Leaking Freon is a possibility if your air conditioner loses cooling power. You might also notice other indications of a Freon leak, such as a weird sound or ice buildup.

Freon leaks aren’t inevitable; they usually result from wear and tear, aging components, or defective parts. Weak or stressed air conditioner parts are often prone to leaks. Repairing leaking parts and recharging the Freon is necessary to restore the air conditioner to good working order. Leaks should never be ignored as they can be detrimental to your health and the air conditioner’s performance.

What is Freon?

Freon, a name trademarked by DuPont, is a colorless gas used as a refrigerant to cool warm air. Freon is a hydrochlorofluorocarbon (HCFC) used in some air conditioning units, freezers, and even dehumidifiers. The most common type of Freon found in modern homes is Freon 22, also known by the generic name R-22.

AC Freon is considered a “Class II” ozone-depleting substance by the Environmental Protection Agency (EPA) and is being phased out of use under the Clean Air Act. The phaseout also includes the refrigerant blend R-410A and other blends which contain HCFC-22. The EPA created a schedule to phase out Freon and other HCFCs. Consequently, an appliance manufactured after 2005 is unlikely to have Freon, and the law prohibits appliances made after 2010 from containing Freon. As of 2020, Freon can no longer be manufactured or imported to the United States. Freon continues to be available for old appliances, but as the supply dwindles, the cost increases.

pink R-410A refrigerant freon tank

If your air conditioner was manufactured after 2010, it uses another refrigerant blend besides Freon. Even so, any refrigerant can leak. The signs and causes of leaks are the same regardless of the refrigerant blend. If you're wondering what kind of Freon my AC uses, the information can be found on the unit's label. "R-22" indicates Freon, while R410A and R132 are other refrigerant blends.

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Signs of a Freon Leak

An air conditioner must contain the appropriate amount of refrigerant to function correctly. Too little or too much refrigerant affects operation. Refrigerants do not deplete over time as a result of usage. A low refrigerant level indicates that it’s leaking or it was underfilled when installed or serviced.

Five signs of a Freon leak:

  • Lack of airflow
  • Warm air
  • Ice buildup
  • Increased energy bills
  • Hissing sounds
man checking air conditioner airflow from a wall vent

1. Lack of Airflow

Air conditioners use refrigerants to cool warm indoor air. The cooled air is blown throughout the house via the ducts and vents. When a refrigerant leak occurs, the air conditioner functions improperly. You may notice less cool air blowing from the vents or it taking longer to cool the house.

young couple fanning with papers and small table fan because freon leak causing air conditioner is blowing warm air

2. Air Conditioner is Blowing Warm Air

Air conditioners do not produce cold air; they remove the heat from warm air. The home’s warm air passes over cold, refrigerant-filled evaporator coils located in the air conditioner’s indoor unit. The refrigerant absorbs the heat and humidity from the air, and the freshly cooled air is blown through the vents.

When the amount of refrigerant is low due to a leak, the refrigerant is incapable of adequately absorbing heat. The air conditioner's warm air is blown back out through the vents.

Remember that warm air or a lack of airflow can indicate other issues, such as a dirty air filter or clogged condensate line.

air conditioner freon leak causing ice buildup on evaporator coil

3. Ice Buildup

If your AC is freezing up, it can indicate a leak. Refrigerant circulates through the evaporator coils to remove heat and humidity from the home’s air. Condensation is produced when the cold refrigerant circulating through the coils meets the warm air. Typically, the condensation evaporates, and the excess drips into the drain pan. If the refrigerant level is inadequate, the coils cannot properly absorb heat, and the condensation may freeze.

Puddles near the unit often indicate a refrigerant leak. These puddles occur when the ice buildup on the coils thaws between cooling cycles and drips onto the floor beneath the unit.

man looking shocked at increased energy bill because of air conditioner freon leak

4. Increased Energy Bills

During a normal cooling cycle, the thermostat clicks off the system when the house reaches the desired temperature. An air conditioner with a refrigerant leak blows less cool air or warm air back into the home. The system will continuously run as it tries to cool the house to the thermostat setting. It’s a vicious cycle that results in higher than normal electricity bills.

closeup of man holding hand to ear listing to hissing sound of air conditioner freon leak

5. Hissing Sounds

The refrigerant within the AC unit is pressurized. If there is a leak, the sound of the refrigerant gas escaping may be audible. If the leak is large, it may make a hissing sound like a popped tire or even a gurgling sound. Hissing or other weird sounds from your AC can indicate other problems.

Is a Freon Leak in Your Home Dangerous?

A Freon leak in your home is not dangerous per se. Exposure to Freon may cause mild or no symptoms, and there are no known long-term effects. Freon quickly dissipates into the air, so unless you sit near the leak for an extended period, it is unlikely you will experience symptoms.

Freon leaks usually occur outdoors, but leaks can occur indoors. Freon gas is heavier than air and sinks to ground level. Children and pets are more susceptible to symptoms due to being lower to the ground and of smaller size. If you locate a leak within your home, vacate the premises, open windows and turn on fans to ventilate the house, and call an HVAC service immediately.

Symptoms of Freon Poisoning

The chances of incurring Freon poisoning from a leak in your home are very low. Freon poisoning only occurs when it is intentionally inhaled or leaks into a small, unventilated area. However, if you are sitting near a leak for a prolonged period, you may begin to experience symptoms. The symptoms should dissipate when you move away from the leak.

Symptoms include:

  • Shortness of breath
  • Coughing
  • Dizziness
  • Loss of coordination
  • Poor concentration
  • Skin rash
  • Nausea
  • Vomiting
  • Headache
  • Irritated eyes, nose, & throat

Severe symptoms include:

  • Seizures
  • Blood in vomit
  • Irregular heartbeat
  • Unconsciousness
  • Fluid or blood in the lungs
  • Breathing difficulties
  • Confusion
  • Coma
  • Sudden death

Where are Refrigerant Leaks Found?

Refrigerant leaks typically occur at the Schrader valve, valve cores, evaporator coils, copper lines, “U” connectors, weld joints, electrical connection to the compressor body, or the copper tubing. Leaks most often occur in the evaporator coil where the metal is weak or stressed, such as the “U” joint, the welds, and parts that receive a lot of vibration.

HVAC professional looking for freon leak in home air conditioner

Causes of a Freon Leak

Freon leaks usually develop as the air conditioner ages and parts wear down or degrade. Leaks can also be the result of human error or mechanical defects.

Common causes of refrigerant leaks:

  • Excessive vibration
  • Improper installation
  • Factory defects
  • Wear and tear
  • Corrosion

Excessive Vibration

Isolation inhibitors reduce vibrations within the air conditioning unit. The air conditioning unit may vibrate excessively if the isolation inhibitors are defective or worn out. These vibrations can cause refrigerant lines to crack and leak.

Improper Installation

Excessive vibrations within the air conditioning unit can be due to improper installation. These vibrations can crack refrigeration lines and cause leakage.

Factory Defects

Sometimes air conditioners are just plain defective. If the unit has been improperly working since it was purchased, the cause may be a factory defect.

Wear and Tear

Over time, parts on the AC unit wear out, become damaged, or rust. If the unit was installed many years ago, regular wear and tear might be the culprit.


Corrosion of the copper lines in the AC unit sometimes occurs. This corrosion may be caused by a chemical reaction that results in the corrosive chemical formaldehyde. Deterioration may also be caused by chloride, fluoride, or dog urine.

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What to Do If You Suspect a Freon Leak

Regular AC unit inspections can help identify Freon leaks before they become too problematic. If you suspect your unit is leaking Freon, contact an HVAC technician to inspect it. The technician can repair the leak and recharge the Freon. Only certified technicians may purchase Freon by law, so repairing a Freon leak is not a do-it-yourself job.


Air conditioners use Freon or some other refrigerant blend to cool the air inside your home. Occasionally, refrigerant leaks occur. A lack of cooling power indicates a leak, but you may also notice hissing sounds or ice buildup on the evaporator coils. Leaks usually develop as the unit ages and parts degrade.

If you suspect a Freon leak, immediately turn off the air conditioning system, ventilate the house, and call an HVAC technician. The chance of sustaining Freon poisoning is low, but running the system with a leak can damage it, and Freon will continue to leak even when the system is off. A technician certified in the handling of refrigerants will inspect the unit for leaks and repair them.

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