3 Central AC Refrigerant Leak Symptoms


If you’re experiencing AC trouble, one of the first things a technician will check is how much refrigerant is in your air conditioning system.

Since refrigerant circulates throughout your AC system in a closed loop, the only way for refrigerant to escape is if there is a leak somewhere in your air conditioner. If a professional finds a leak, they will need to repair it and then recharge the system with the appropriate amount of refrigerant.

So, how do you know you have a refrigerant leak?

If your AC is low on refrigerant, you may notice symptoms such as:

  1. Reduced cooling power
  2. Hissing or gurgling sounds coming from the AC
  3. Ice on refrigerant lines or evaporator coil

In this blog, we’ll explain each of these symptoms in more detail below. We’ll also tell you right off the bat that fixing a refrigerant leak should only be handled by a certified HVAC technician. Refrigerant can be potentially harmful to humans if handled improperly, so only a trained professional should repair refrigerant-related problems in your AC.

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Refrigerant leak symptom #1: Reduced cooling power

Refrigerant is designed to absorb the heat from the unconditioned air inside your home, which is ultimately how your home is cooled.

Without enough refrigerant to absorb heat, your AC will struggle to cool your home, resulting in a loss of cooling power.

Some signs of reduced cooling power include:

  • Warm air coming from the vents (when the thermostat is set to COOL)
  • Your house never reaches the set temperature on your thermostat
  • Your AC is running longer than normal to cool your home (which means you’ll also notice a spike in your monthly electric bill)

If you notice any of the above signs, you should have a professional inspect your AC and troubleshoot the problem.

Symptom #2: Hissing or gurgling sounds coming from the AC

When a refrigerant leak forms in your AC, it’s not uncommon to hear a hissing sound, which is caused by a change of pressure (similar to air escaping from a balloon) in the refrigerant lines.

Likewise, you may also hear a gurgling sound, which could be the sound of liquid refrigerant leaking from the system.

Since refrigerant lines run through almost every part of your air conditioner, you may hear a hissing or gurgling coming from all major components including:

  • The indoor unit (which can be located in an attic, closet or crawl space)
  • The outdoor unit
  • The refrigerant lines that connect the indoor and outdoor units
refrigerant line diagram

Refrigerant lines connect the indoor and outdoor units

If you hear these abnormal noises coming from anywhere around your air conditioner, contact a professional immediately for assistance.

Symptom #3: Ice on refrigerant lines or evaporator coil

If your AC has a refrigerant leak, that means the pressure inside your system is unbalanced, which can cause the refrigerant to get colder than normal design conditions. When the refrigerant gets too cold, ice can form on the copper refrigerant lines and the evaporator coil (located inside the indoor unit).

So, how do you know if a refrigerant line or evaporator coil is frozen? One way to tell is to go outside and look at the lines that connect to the outside unit. If you see ice on the refrigerant lines, that’s one indication there’s a refrigerant leak inside your system.

ice on refrigerant line

Refrigerant lines connecting to the outdoor unit

Of course, there may be ice on a section of line that’s hidden from view. A professional can inspect your refrigerant lines to find any frozen sections.

The evaporator coil is located inside the indoor unit, which means you’ll have to unscrew the access panels in order to see it directly. We don’t recommend tampering with the indoor unit unless you have experience working with air conditioners. That said, if you see water pooled around the indoor unit, that’s a sign that the evaporator coil is frozen and is unthawing slowly between cooling cycles.

If you see ice on the refrigerant lines or water pooled around your indoor unit, call an HVAC professional to check for a leak.

Want a San Marcos professional to fix your refrigerant leak?

Schedule service today

Our highly-trained technicians can quickly diagnose what is causing your AC problem—whether it’s a refrigerant leak or something else. At Reliable Air, we offer honest prices and same-day service with 2-hour scheduling for all AC repairs.