Ah! The sweet cold air from your ac unit is such a life-saver on blazing hot summer days. If only your AC unit worked smoothly all the time! If your AC unit is cleaned and serviced regularly, your chances of coming across a significant issue are far reduced, but problems still occasionally happen.
Along with water leaks and dirty filters, an AC refrigerant leak is a common problem you may need to address. Sometimes an odd smell may be coming from the vicinity of your AC unit, or even blowing directly in your face with the cold, or not so cold, stream of air.
Up until 2010, the primary refrigerant used in AC units was Freon. Freon production in the United States stopped in 2020, and it is no longer being imported. If you have a unit that was manufactured before 2010, you may be wondering how to identify a Freon leak.
Does Freon Smell?
The smell of Freon appears to be highly subjective. Ask a crowd what Freon smells like, and you’ll get multiple answers, including the claim that it has no smell unless it is very highly concentrated. Most commonly, though, you’ll hear that Freon has a sweet “chloroform” smell or a musty smell.
What is Freon?
Freon is a registered trademark used for several halocarbon compounds produced by The Chemours Company. Freons are gases or liquids that have usually been used as aerosol propellants and as refrigerants. These halocarbon products are stable, nonflammable, and low toxicity.
Freon is specifically a brand name for certain refrigerants manufactured by The Chemours Company, and so not all refrigerants are labeled as Freon.
What does Freon do?
In most refrigerators and air conditioners, Freon undergoes an evaporation process over and over to lower the air temperature.
Here’s how it works: Your unit has a compressor that compresses cold Freon gas. Being compressed, increasing pressure makes the Freon gas very hot. Once it has been sufficiently heated, the Freon gas moves into and through a set of copper coils. This lowers its heat which causes the gas to convert to liquid.
Next comes the thermal expansion valve or TEV. The TEV regulates the amount of refrigerant that is released into the evaporator. This regulates the superheat. Superheat refers to the temperature of this vapor above its boiling point when it is evaporating pressure.
Being without superheating means the refrigerant will not be fully vaporized, and the unit will have liquid go back into the compressor. Too much superheat means there is probably not enough refrigerant flowing through the evaporator coil. This will prevent the exchange of heat that cools the air coming out of your AC.
When Freon liquid flows through the thermal expansion valve, it cools down to evaporation temperatures. This results in low-pressure Freon gas. The Freon gas, now cold, passes into more coils where it absorbs heat from the air, cooling it.
This cooled air is then pumped through your AC unit’s filters, cleaning it of pollen, smoke, and dust.
Can You Smell Freon?
If you’re smelling a strange odor, in your car or house, around the AC units or refrigerators, the likelihood of it being Freon is relatively small. Refrigerants are heavier than air, four times heavier, and so they hang out near the floor.
Refrigerants are also highly volatile, meaning they don’t stay in liquid form unless pressurized, and they vaporize quickly.
What Does Freon Smell Like?
As mentioned earlier, the smell of Freon, or refrigerants in general, appears highly subjective. Refrigerants are colorless gases that often have no odor, but when they do can smell like “sweet ethanol,” chloroform, or nail polish remover (acetone).
Others describe the smell as musty. If it smells like something has gone bad in your refrigerator, but you’ve cleaned it out and can’t find the source, check for a refrigerant leak.
If your AC smells musty, it’s far more likely to be mold of some kind inside the unit. Moldy coils blocked condensation drains, or dirty filters could be the cause of the smell.
Other descriptions of the smell of Freon include chlorine, copper, vinyl, plastic, cat urine, paint, garlic, apples, and bananas! That’s quite a range, and it turns out everyone perceives smell differently.
With about 400 smell receptors per nose and more than 900,00 variations in the genes responsible for how these receptors react to smells and communicate with the brain, the difference in individual perception of smell is understandable.
The smell of Freon is most likely to be a very faint chemical smell, possibly difficult to detect or identify.
Is The Smell of Freon Harmful?
Yes, breathing Freon can be harmful to your health. Although it’s not likely the small amount of refrigerant in your AC unit will be seriously dangerous, remember it also sinks to the floor. Still, keep an eye out for symptoms if you suspect a leak.
Freon and other refrigerants can cut off your oxygen supply when inhaled. As other gases replace your oxygen, you will suffer from hypoxia.
Symptoms of mild to moderate refrigerant poisoning include:
- Headache
- Irritation of the eyes, ears, and throat
- Cough
- Nausea
- Vomiting
- Dizziness
- Chemical burn of the skin
- Frostbite (liquid Freon)
Where do Most Freon Leaks Occur?
Typical places for Freon leaks to occur are the evaporator coils, condenser coils, and refrigerant line sets. Evaporator coils are made of conductive metals and are located in or near the air handler and blower fan.
Regularly dusting the evaporator coils helps them perform more efficiently. You’ll also be in a position the check for corrosion or frost and catch these problems early.
Condenser coils perform the second half of the cooling cycle. The condenser is in the large unit outside your house. The condenser coils are where the refrigerant releases the heat it gathered inside your house.
Check the condenser and its fan frequently to make sure it doesn’t have a build-up of debris. If you need to clean the condenser, turn off the power to the AC system and sweep away the debris with a stiff brush.
If you see ice or frost on the condenser, this indicates an airflow problem or low refrigerant levels. To see if the problem is airflow, check the air filter, air registers, and vents.
Also, check for duct blockage and make sure the evaporator coil is clean.
How do you know if you have a Freon leak?
Some signs of a Freon leak are warm or room temp air blowing from the unit, low airflow, ice or frost on refrigerant lines, and hearing a noise like bubbling or hissing coming from the unit.
What Color is Freon When it Leaks from an Air Conditioner?
Freon itself is colorless, but it is usually blended with oil when used in a refrigeration unit. This oil can be green or yellow. Freon could also be mixed with dust from in or around the unit. Thus an oily, dusty residue could indicate a leak.
Summary
Freon and other refrigerants may put off a slight chemical smell, but it’s best not to rely on this to tell you if you leak. Physically inspect your unit for signs of leaks anytime you suspect a problem and have it professionally inspected annually.