Refrigerant Charge

Why the exact charge matters

Refrigerant is the working fluid that carries heat from the evaporator coil indoors to the condenser coil outside. The system is engineered around a specific quantity of it, and technicians verify the charge by measuring superheat and subcooling with gauges and thermometers rather than guessing. Too little refrigerant starves the evaporator coil, which can ice over, blow lukewarm air, and run long, inefficient cycles. Too much floods the system, raises pressures, and risks sending liquid refrigerant into the compressor, the most expensive component to replace.

Refrigerant does not get used up. A sealed system should hold its charge indefinitely, so a low reading almost always means a leak, not normal wear.

Repair decisions when your system is low on refrigerant

Simply topping off a leaking system buys a few weeks or months while the leak keeps growing, so the better practice is to find and fix the leak, then weigh and set the charge. For older systems running the phased-out R-22 refrigerant, repair economics tilt quickly toward replacement, since R-22 is no longer produced and modern equipment uses different refrigerants entirely. If your AC loses cooling power each summer or the coil keeps freezing, ask for a leak search rather than a recharge. PJ MAC HVAC's AC repair service covers leak diagnosis and charge correction on all major brands, including Lennox, Carrier, Trane, and Goodman.