Troubleshooting AC Issues in San Diego – Expert Diagnostics That Pinpoint the Exact Problem Fast

When your AC runs but doesn't cool, suspect low refrigerant, dirty coils, or a bad compressor. Low refrigerant from leaks prevents heat transfer. Dirt buildup on outdoor condenser coils blocks heat release, common in San Diego's dusty inland areas. A failing compressor runs but doesn't compress refrigerant properly. Check if your outdoor unit's fan spins and feels hot. Frozen indoor coils indicate airflow problems from dirty filters or blocked returns. Undersized systems struggle on 90-degree days but work fine in milder weather. Professional diagnosis identifies the exact cause.

Set your AC to 78 degrees when outdoor temperatures hit 100 degrees. This 22-degree differential prevents system overwork while maintaining comfort. San Diego rarely reaches 100 degrees, but inland communities like Santee and El Cajon experience these extremes. Going below 75 degrees forces your AC to run continuously without cycling off, which reduces dehumidification and increases wear. Use ceiling fans to create wind chill effect, making 78 feel like 75. Close blinds on west-facing windows during afternoon heat. Your system needs reasonable expectations to function efficiently.

Your thermostat reads 78 despite being set to 72 because your AC can't keep up with heat gain. Common causes include undersized equipment, poor insulation, air leaks around windows, or extreme outdoor temperatures. In San Diego's coastal areas, afternoon sun through west windows creates intense heat load. Dirty condenser coils reduce cooling capacity by 30%. Low refrigerant from leaks prevents proper heat removal. Duct leaks in attics waste 20-40% of cooled air. Your system may need professional cleaning, refrigerant recharge, or capacity evaluation to match your home's actual cooling needs.

A bad capacitor shows specific symptoms you can identify. Listen for a humming sound from your outdoor unit when AC turns on but the fan doesn't spin. You might see the fan start slowly or need a manual push to begin spinning. The unit may shut off randomly after short run times. Bulging or leaking capacitors fail quickly in San Diego's heat. Never touch a capacitor, even when power is off, because they store dangerous electrical charges. Capacitors typically last 10-15 years but fail faster in direct sun. Professional replacement takes 30 minutes and prevents compressor damage.

Your AC should run 15-20 minute cycles on a 100-degree day, cycling off briefly between runs. Properly sized systems in San Diego homes run 70-80% of the time during extreme heat but still achieve short breaks. Continuous 24-hour operation without cycling off indicates undersized equipment, low refrigerant, dirty coils, or excessive heat gain. Inland San Diego communities experience sustained triple-digit heat where even healthy systems run almost constantly. This is normal during heat waves. However, if your system never reaches set temperature or runs nonstop in moderate weather, schedule professional evaluation.

Air conditioners last 12-15 years in San Diego with proper maintenance. Coastal humidity and salt air reduce lifespan to 10-12 years for homes near the ocean. Inland desert heat in areas like Ramona or Alpine stresses components, shortening life to 12-14 years. Quality installation, annual maintenance, and regular filter changes extend equipment life. Neglected systems fail at 8-10 years. Signs your AC nears end of life include frequent repairs, rising energy bills, R-22 refrigerant that's expensive to refill, and uneven cooling. Plan replacement when repair costs approach 50% of new equipment cost.