Refrigerant Charge Calculator

How It Works

Refrigerant charge is the exact amount of refrigerant your AC or heat pump needs to operate correctly. Every system ships from the factory pre-charged for a standard lineset length, typically 15 feet. If your indoor and outdoor units are farther apart, a technician must add refrigerant to compensate. Too little refrigerant (undercharged) causes the evaporator to starve, reducing cooling and potentially freezing the coil. Too much (overcharged) raises head pressure, reduces efficiency, and can damage the compressor. R-410A is the current standard, replacing ozone-depleting R-22 which is now extremely expensive because production was phased out in 2020. R-32 is a newer lower-GWP alternative gaining adoption. Proper charge is verified by measuring superheat (at the evaporator) and subcooling (at the condenser) — these temperatures confirm the refrigerant is changing state at the right points in the cycle.