When the air conditioner stops keeping up
In the hot inland valleys of California and the high desert around Reno, an air conditioner that fails in July is more than an inconvenience. Knowing the common failure points helps you describe the problem clearly, understand the diagnosis and judge whether a repair makes sense.
Common air conditioning problems
- Warm air from the vents. Often a failed capacitor or contactor at the outdoor unit, a tripped breaker, a clogged filter, or a refrigerant leak. A capacitor is a common, relatively inexpensive repair; a leak needs to be found and fixed, not just topped off.
- Ice on the refrigerant lines or indoor coil. Usually caused by restricted airflow (a dirty filter or coil, a weak blower) or low refrigerant. Turn the cooling off and let the ice melt before running it again, or you risk damaging the compressor.
- The outdoor unit hums but the fan doesn't spin. Frequently a failed fan motor or capacitor. Running the system in this state can overheat the compressor.
- Water around the indoor unit. A clogged condensate drain or a cracked drain pan. In attic installations this can damage ceilings quickly, so don't ignore it.
- Short cycling or constant running. Can point to a thermostat problem, an incorrectly sized system, low refrigerant or a dirty outdoor coil that can't shed heat.
- Breakers that trip when the compressor starts. This needs an electrical diagnosis, not repeated resets.
Repair or replace?
Many air conditioner repairs are routine: capacitors, contactors, fan motors, drain cleaning and thermostat replacement. Compressor failures and large refrigerant leaks in the indoor coil are the expensive ones. When one of those hits a system that is near the end of its life, replacement is often the better value.
If you replace, efficiency standards matter. In California and Nevada, split-system central air conditioners installed since January 1, 2023 must meet the Department of Energy's Southwest regional minimums; Idaho and Washington fall under the North region's rules. Your city page lists the figures with a link to the Department of Energy. A contractor should quote equipment that meets the standard for your region and size it with a load calculation, not by guessing from the old unit.
Older systems that use R-22 refrigerant are expensive to recharge, because that refrigerant is no longer produced for new equipment in the United States. If your system uses R-22 and has a leak, ask for a replacement price alongside the repair price.
What an AC service call should cover
- Checking electrical components: capacitor, contactor, wiring and disconnect.
- Measuring refrigerant pressures and temperatures to judge the charge, and leak searching if the charge is low.
- Inspecting and cleaning the outdoor coil and checking the indoor coil and filter.
- Clearing the condensate drain and checking the pan and safety switch.
- Measuring the temperature split between return and supply air.
- A written report of findings, with the price of each recommended repair.
Questions to ask the contractor
- If refrigerant is low, where is the leak, and will you repair it or only recharge?
- Which refrigerant does my system use, and what does that mean for repair cost?
- If replacement makes sense, what size do you recommend and how did you work it out?
- Does the quote include permits, disposal of the old equipment, and any electrical work?
Ask for every price in writing before work begins.