Quick Answer
Signs of an AC refrigerant leak include: warm air from vents, ice on refrigerant lines or evaporator coil, hissing sounds, higher energy bills, and the system running constantly. Repair costs range from $200-$800 for recharge plus leak repair. Simply recharging refrigerant without fixing the leak is a temporary fix—the refrigerant will leak out again.
Refrigerant is the lifeblood of your air conditioner. When it leaks, your AC can't cool effectively—and continuing to run a low-charge system can damage the compressor. Here's how to recognize a refrigerant leak and what it costs to fix.
What Is Refrigerant and Why Does It Matter?
Refrigerant is the chemical that absorbs heat inside your home and releases it outside. Your AC doesn't "use up" refrigerant—it circulates in a closed loop. If refrigerant is low, it means there's a leak somewhere in the system.
Common Refrigerant Types
Signs of a Refrigerant Leak
1. AC Blowing Warm Air
The most obvious sign. With insufficient refrigerant, the evaporator coil can't absorb enough heat. Supply air temperature is warmer than it should be (should be 15-20°F cooler than return air).
2. Ice on Refrigerant Lines or Coil
Counterintuitively, low refrigerant causes the evaporator coil to get TOO cold, leading to ice formation. If you see ice on the copper lines or the indoor coil, refrigerant issues are likely.
3. Hissing or Bubbling Sounds
A hissing sound from the refrigerant lines may indicate refrigerant escaping from a leak. Bubbling sounds can occur when the leak is larger.
4. Higher Energy Bills
A system low on refrigerant works harder and runs longer to achieve the same cooling, consuming more electricity.
5. System Runs Constantly
Because cooling capacity is reduced, the AC runs almost continuously trying to reach the thermostat setpoint.
6. Humidity Problems
Low refrigerant reduces the system's ability to remove humidity. Your home may feel clammy even when the AC is running.
What Causes Refrigerant Leaks?
- Vibration wear – Copper tubing fatigues over time from vibration
- Corrosion – Particularly on evaporator coils exposed to humidity and chemicals
- Factory defects – Manufacturing flaws in coils or connections
- Physical damage – Lawn equipment hitting outdoor unit, hail, etc.
- Age – Older systems develop leaks as materials degrade
- Poor installation – Improper brazing or flare connections
Refrigerant Leak Repair Costs
Refrigerant Leak Repair Pricing
| Service | Cost | Notes |
|---|---|---|
| Leak search/detection | $100-$200 | Finding the leak location |
| Minor leak repair (accessible) | $200-$500 | Simple fix on visible tubing |
| Evaporator coil leak repair | $400-$900 | More complex repair |
| Evaporator coil replacement | $1,800-$3,500 | If repair isn't feasible |
| Refrigerant recharge (R-410A) | $200-$800 | After leak is repaired |
| Refrigerant recharge (R-22) | $400-$800 | Phased out, expensive |
Should You Repair or Replace?
Not all refrigerant leaks are worth repairing:
| Situation | Recommendation |
|---|---|
| System under 8 years, accessible leak | Repair usually makes sense |
| System 8-12 years, simple leak | Case-by-case, consider repair |
| System over 12 years, any leak | Consider replacement |
| Evaporator coil leak on older system | Often better to replace system |
| R-22 system with leak | Replacement usually best (R-22 is expensive) |
| Multiple leaks or second occurrence | Replacement recommended |
The "Just Add Refrigerant" Trap
The R-22 (Freon) Problem
If your system uses R-22 refrigerant (most systems installed before 2010), you face a challenge. R-22 was phased out in 2020 and is now extremely expensive—$80-$150+ per pound versus $10-$20 for R-410A.
For R-22 systems with leaks, replacement often makes more financial sense than paying premium prices for refrigerant that will just leak out again.
Can You Prevent Refrigerant Leaks?
Some leaks are unavoidable, but you can reduce risk:
- Annual maintenance – Technicians can spot early corrosion or wear
- Keep outdoor unit clear – Prevent physical damage from debris
- Proper installation – Quality installation reduces connection failures
- Address vibration issues – Excessive vibration accelerates tubing fatigue
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Written by
Kodiak HVAC Team
HVAC professional at Kodiak Heating & Cooling.