Quick Answer
Okay so here's the quick and dirty. Your AC is running but the air's warm. 90% of the time, it's something simple you can fix yourself. First thing you're gonna check is your air filter. If it's clogged solid with dust and pet hair, air can't get through. Simple. After that, look at the big unit outside. Is it covered in grass clippings and that fluffy cottonwood stuff? Clean it. If it's iced up inside, that's a whole other can of worms, usually low refrigerant or bad airflow. A filter's a $15 fix. A pro call for a refrigerant leak? You're looking at a few hundred bucks, easy.
Common Symptoms
Possible Causes
Step-by-Step Diagnosis
Step 1
Check the thermostat to make sure it's set to 'Cool', 'Auto', and a low temperature.
Step 2
Turn off the system and inspect the air filter. If it's dirty, replace it immediately.
Step 3
Go outside and check the condenser unit. Make sure the fan is spinning and the coils are clean of debris.
Step 4
Turn off cooling and run the fan to check the indoor unit for ice. If it's frozen, let it thaw completely.
Step 5
Check the circuit breakers in your electrical panel to make sure none have tripped.
Step 6
Walk around the house and make sure all your supply and return vents are open and not blocked by furniture.
DIY vs Professional Costs
| Repair Type | DIY Cost | Professional Cost | Time Required |
|---|---|---|---|
Replace Air Filter | $10-30 | $100-150 (part of a service call) | 5 minutes |
Clean Outdoor Coils | $0-20 (for cleaner spray) | $125-250 | 30-60 minutes |
Clear Condensate Drain | $5-15 (vinegar, shop vac) | $100-250 | 30 minutes |
Replace a Capacitor | $20-50 (for the part) | $150-400 | 1-2 hours (if you know what you're doing) |
Refrigerant Recharge & Leak Fix | N/A - ILLEGAL & DANGEROUS | $300-800+ (depending on leak) | 2-4 hours |
When to Call a Professional Hvac
- The indoor coil freezes up repeatedly, even after you've changed the filter and let it thaw.
- The outdoor unit's fan or compressor is not running, or you just hear a humming/buzzing sound.
- You hear any unusual loud noises like grinding, screeching, or banging from either the indoor or outdoor unit.
- You smell electrical burning or see smoke coming from any part of the system.
- You've tried all the basic DIY steps (filter, coils, thermostat, breakers) and the AC is still not cooling.
Prevention Tips
- Change your air filters religiously, at least every 1-3 months.
- Schedule an annual professional AC tune-up in the spring, before the cooling season starts.
- Keep the outdoor condenser unit clear of debris, leaves, and overgrown bushes, maintaining at least 2 feet of clearance.
- Make sure all your indoor supply and return vents are open and not blocked by furniture, rugs, or drapes.
- Periodically pour a cup of distilled white vinegar down the condensate drain line to prevent clogs.
Frequently Asked Questions
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