Usually on the smaller side
A clogged condensate drain. Algae and sludge block the line and water backs up or trips the float switch. It is mostly labor and often quick (more on AC drain line cleaning). A weak capacitor or worn contactor. These small electrical parts in the outdoor unit are common failures in Houston heat. The part is inexpensive; the cost is the visit and the testing to be sure nothing else is failing. A thermostat problem. Sometimes batteries or settings, sometimes a swap; see thermostat repair and installation.
In the middle
A fan motor. The outdoor fan motor or the indoor blower motor costs more than a capacitor and takes more labor. A refrigerant leak. Low refrigerant means a leak somewhere. Topping it off without finding the leak only buys time. Finding and fixing the leak is the real repair, and the cost depends on where the leak is. The type of refrigerant also matters: many older systems use R-410A, while newer equipment uses R-454B or R-32. Systems already running R-410A can still be repaired. A frozen evaporator coil. Ice is a symptom. The cause may be airflow, a filter, a blower or low refrigerant, and the price follows the cause.
Usually the large ones
A compressor. It is the heart of the system and the costliest single part. A failed compressor on an older unit is often where repair stops making sense. A leaking evaporator coil or condenser coil. Reaching a coil inside an air handler or above a furnace is a bigger job than the part alone suggests. More than one failure at once. A bad capacitor can overwork a motor or compressor, which is why we check the whole system instead of swapping the first part we find.
What else moves the price
Access. An outdoor unit on a pad is easy; an air handler in a tight attic is slower. Age and part availability. A part for an older model may take time to find. Warranty status. A manufacturer’s parts warranty may cover the part but usually not the labor. Check your paperwork, and tell us the make and model. Time of year. Houston’s average first 90°F day is around May 6, so the busy season starts in spring.
Sources: EPA refrigerant transition rules (R-410A, R-454B, R-32); NWS Houston/Galveston climate records. Updated November 2026.
