A sealed system should never need refrigerant. If it does, there is a leak, and this is the single most useful thing to understand before paying for a recharge. The signs are cooling that weakens year on year, ice forming on the line set or evaporator coil, a hissing or bubbling sound near the indoor unit, and longer run times for less result. Common leak points are the evaporator coil itself, brazed joints at the line set, Schrader valve cores, and corrosion at the outdoor coil.
A recharge without finding the leak is a repeat expense rather than a fix, and refrigerant costs have risen sharply as older blends are phased down. Running low charge also makes the compressor run hot, and compressor replacement is usually the most expensive repair on the system. Ask for the leak to be located and quoted before agreeing to add refrigerant. Pro HVAC connects homeowners in Upper Arlington, OH with HVAC professionals who can locate and repair the leak. Call (321) 463-9811.