Refrigerant circulates in a sealed loop. A low charge means it escaped somewhere, and newer coils are not immune: leaks turn up at brazed joints, at service valves and in the coil tubing itself. The signs are longer run times, air that is cool but never cold, and sometimes ice on the copper line at the outdoor unit.
Most Lynn Haven systems from 2018 to 2020 run on R-410A, which is being phased down as new equipment moves to R-454B, so a proper repair beats a recharge you will repeat next year. We locate the leak, quote the repair, and recharge to the manufacturer’s specification. Locally, finding and repairing a leak typically runs $400 to $1,600 plus refrigerant, and an evaporator coil $1,200 to $2,800, both market ranges rather than a Quincy’s quote. If the coil is still inside its parts warranty, the part may be covered while the labor is not.