Short answer: An air conditioner's refrigerant circulates in a sealed loop and is never used up. If an AC is low on gas, it is leaking. A "gas refill" alone restores cooling only until the new gas leaks out too, often within weeks or months. A proper repair finds the leak, fixes it, vacuums the system, and then charges the correct gas to specification.
Refill Only vs Leak Repair
| Refill only | Leak repair + refill | |
|---|---|---|
| Finds the leak | No | Yes (nitrogen pressure test) |
| Fixes the leak | No | Yes (re-flare, braze or coil repair) |
| Removes moisture | Rarely | Yes (vacuum pump) |
| How long it lasts | Weeks to months | The rest of the AC's life, if done well |
| Cost over two years | Pays repeatedly | Pays once |
Where AC Leaks Usually Are
Flare joints at the indoor and outdoor units (the most common, often from a rushed installation), pinholes in the indoor coil from corrosion, pipes rubbing against a wall or bracket, and worn service valve cores.
What should I ask a technician who says I need gas?
"Where is the leak, and how will you fix it?" A good technician can answer both.
What gas does my AC use?
Check the label on the outdoor unit: usually R32, R410A or R22. They can't be mixed.
