Your air conditioner relies on refrigerant in a similar way your body depends on blood. When blood flows
through your body, the blood vessels will expand and allow you to keep cool. Similarly, when refrigerant
properly flows through your unit, your air conditioner can maintain a stable core temperature.
But too little refrigerant can spell doom for your cooling system in the same way too little blood will
lead to a variety of health problems. Without enough refrigerant, your air conditioner’s components will
break and ultimately fail, resulting in a premature ending for your machine.
So how can you tell if your air conditioner has sprung a leak? Your senses may give you a clue.
1. You Hear a Hissing Sound
Refrigerant starts as a liquid in your air conditioner’s compressor. This liquid cycles through a closed-
loop system, so you never need to top it up like you would your car’s oil or wiper fluids.
As the liquid goes through the system, it absorbs heat and converts into a gas. To continue cooling your
home, your air conditioner compresses the gas by putting it under high pressure. The pressure creates heat,
which your air conditioner redirects outdoors. Once the gas cools, it converts into a liquid again and the
But if your air conditioner springs a leak, that high-pressure gas will force its way out of the smallest
holes in your line. As it escapes, the gas will emit a hissing or bubbling sound.
2. You Feel Warm Air From the Registers
Your air conditioner could blow warm air for a variety of reasons. Your filter or condenser coils could
have a clog. Your outside unit may have lost power. Or your thermostat may have the wrong fan setting.
But if you’ve checked all of these possible issues and still can’t correct the problem, your unit may need
more refrigerant. As mentioned above, refrigerant remains responsible for absorbing heat from the air. When
your unit doesn’t have enough refrigerant, your air conditioner will struggle to cool your home, especially
on hot days.
3. You See Ice Along the Coils
Refrigerant’s primary role is to absorb heat, and when you feel warm air from the registers, you could
naturally assume that your unit doesn’t have enough refrigerant. Along that same line of logic, if you were
to see ice forming along the coils, you might conclude that your unit has too much, not too little,
refrigerant running through your system.
However, when too little refrigerant runs through your indoor coils, the refrigerant won’t have as much
contact with the hot air that blows over the coils. As a result, the refrigerant won’t absorb enough of the
heat to change from a liquid into a gas. The remaining cold liquid will flow back into the refrigerant line.
Any moisture clinging to the outside of the line will freeze, creating a thin layer of ice on your machine.
4. You Smell Ether
The most commonly used refrigerant in air conditioning systems is Puron, more specifically R-410A. This
refrigerant is a non-toxic, non-flammable gas that lacks odor, so when your unit springs a leak, your nose
might not alert you to the problem.
However, older units often relied on R-22 Freon, rather than R-410A. Many manufacturers have since tried
to phase out R-22 in favor of R-410A, as the latter is more environmentally friendly and it absorbs and
releases heat more effectively.
R-22 Freon, like R-410A, is non-toxic and non-flammable. Although R-22 is relatively odorless, a few Freon
brands do emit the faint smell of ether in high concentrations. This smell can seem slightly sweet, giving
the semblance of freshly mowed grass.
But keep in mind that for you to detect ether, your older unit would have had to spring a sizeable and
dangerous leak. Since high concentrations of Freon often lead to dizziness, asphyxia, and loss of
concentration when inhaled, you should use your other senses first before you try to sniff out the problem.
Hire a Technician to Inspect Your Unit
If you notice any of the above issues, turn off your unit, and call in a technician for inspection and
repairs. Your technician should be able to pinpoint the leak and refill your unit with refrigerant. If you
have an older unit that uses R-22, he or she may recommend that you switch to a newer air conditioner to
minimize the likelihood of future leaks.