What should I do if my mini-split is not cooling?

What this symptom usually means

A mini-split that is on but not cooling tells you the system is still powering up and attempting to run, but it is no longer removing enough heat from the room. That is different from a unit that will not turn on at all, and different from a page about freezing, leaking water, or making noise. On this symptom, the key question is whether the head is blowing room-temperature air, only slightly cool air, or weak airflow that never brings the room down to the set point.

What you can observe to narrow it down

If airflow feels normal but the room stays hot, low refrigerant, a control problem, or an outdoor-side issue is more likely than a simple airflow restriction. If airflow is weak from the indoor head, the problem often points to a dirty blower wheel, clogged coil, fan motor issue, or heavy buildup inside the wall cassette. If only one room or zone is not cooling but other indoor heads are, that usually means the fault is local to that head or its controls, not the entire outdoor unit.

Ice on the indoor coil or refrigerant line is an important clue because poor cooling plus icing often starts with restricted airflow or a refrigerant leak. Water around the indoor head can appear when a coil gets too cold, forms ice, and then thaws, so poor cooling and dripping sometimes show up together even though the root cause is not the drain alone. A new hum, buzz, or fan noise during poor cooling can point toward a motor, board, or compressor-speed problem rather than just low charge.

What a technician usually checks on a service visit

A qualified technician will usually verify the operating mode and set point, compare return-air and supply-air temperatures, inspect the indoor coil and blower, and confirm whether the indoor fan is reaching proper speed. They will also check the outdoor section, measure pressures and temperatures if needed, and look for sensor, communication, or inverter fault codes. On multi-zone systems, they will compare how each head responds to isolate whether the problem is in one indoor unit, the branch controls, or the shared outdoor system.

What affects repair cost

Cost depends heavily on whether the fix is cleaning and minor diagnostics or sealed-system and electronics work. Typical 2025-2026 US ranges are roughly $150-$400 for a service call with basic diagnosis or minor cleaning-related correction, about $300-$900 for fan motor, sensor, or drain-pan related repairs that are found during a no-cooling visit, and around $600-$2,000+ for refrigerant leak diagnosis and repair with recharge, control board replacement, or inverter-related parts. Multi-zone systems often cost more to diagnose because the technician has to test each head and the shared outdoor unit.