AC Blowing Warm Air

AC blowing warm air? Learn common causes, easy DIY checks, and HVAC repair costs ($150–$600). Get your AC working again.

Typical repair cost: $150–$600 · DIY difficulty: Easy · About 15–30 minutes.

What usually causes it

• Dirty air filter
• Thermostat set incorrectly
• Low refrigerant
• Frozen evaporator coil
• Compressor failure

What you need

• Replacement air filter

How to fix it yourself

1. Check thermostat is set to 'Cool' and temperature is below room temp
2. Check and replace the air filter if dirty
3. Inspect the outdoor unit — clear debris and ensure it's running
4. Check if the evaporator coil is frozen (turn off AC and let it thaw for 2-3 hours)
5. If none of these fix it, it likely needs refrigerant or compressor repair

When to call a pro

If the air filter is clean and thermostat is correct, you likely need an HVAC tech to check refrigerant levels or the compressor.

Get a fixed price from a local pro