Common Air Conditioning Problems and Practical Fixes (Los Angeles Guide)

Air conditioning in Los Angeles works hard for months at a time, so small issues can quickly turn into comfort and cost problems. Below are the most common HVAC and air conditioning failures homeowners face, plus practical first steps you can take. 1) AC runs but doesn’t cool: Start with the thermostat (cool mode, correct setpoint, fresh batteries). Then check the air filter—if it’s dusty, replace it. A clogged filter restricts airflow and can make the system feel weak. 2) Weak airflow from vents: Inspect supply registers to ensure they’re open and not blocked by furniture. If airflow is still low, the blower, duct leaks, or a dirty evaporator coil may be the cause. 3) Ice on the indoor unit or refrigerant lines: Frozen coils usually mean poor airflow (dirty filter, blocked return) or low refrigerant. Turn the system off to thaw and switch the fan to “on.” If icing returns, request service—refrigerant handling requires a licensed technician. 4) Water leaking near the furnace/air handler: Often caused by a clogged condensate drain line. If safe and accessible, clear the drain and check the drain pan. Persistent leaks can lead to mold or ceiling damage. 5) Strange noises (rattling, buzzing, grinding): Rattling may be loose panels; buzzing can be electrical; grinding may indicate motor or bearing issues. Shut the unit down if the sound is loud or new. 6) Short cycling (frequent starts/stops): This can come from an oversized system, dirty coils, or thermostat placement. It wastes energy and increases wear. In LA’s heat, preventive maintenance—filter changes, coil cleaning, drain checks, and a seasonal tune-up—helps avoid breakdowns and improves efficiency. If you notice burning smells, repeated tripped breakers, or ongoing cooling loss, schedule professional HVAC diagnostics.