Why Is My AC Blowing Warm Air? | Columbia, MO Troubleshooting Guide

It’s 90+ degrees outside in Columbia, MO and your air conditioner is suddenly blowing warm air instead of keeping you cool. Sound familiar? You’re not alone — this is one of the most common AC repair calls we get during summer.

In this guide, the team at PolarCore Heating and Air Conditioning walks you through 5 common reasons your AC might be blowing warm air, and what you should do next.

1. Thermostat Is Set Incorrectly

It might sound simple, but double-check that your thermostat is:

• Set to “Cool” mode (not just “Fan”)
• Set to a temperature lower than the current room temp
• Not stuck in a schedule or eco mode that overrides your settings

If you have a smart thermostat, check for app or Wi-Fi glitches.

2. Dirty Air Filter

A clogged air filter can block airflow and cause your AC to struggle — leading to warm air blowing out of your vents. If it’s been over 90 days since your last filter change, start here.

3. Low Refrigerant

If your AC is blowing lukewarm air or your system runs constantly without cooling, you might have a refrigerant leak. This isn’t a DIY fix — it’s time to call a pro for AC repair in Columbia.

4. Frozen Evaporator Coil

When airflow is restricted (from a dirty filter or duct issues), your indoor coil can freeze over. Ironically, this can stop your AC from cooling and cause it to blow warm or room-temperature air.

5. Outside Unit Not Running

If your indoor fan is working but the outdoor unit is silent, your condenser may have tripped a breaker, overheated, or failed. Check your breaker box — if nothing’s tripped, it’s time for service.

When to Call for AC Repair in Columbia, MO

If basic troubleshooting hasn’t fixed the problem, our licensed HVAC technicians at PolarCore can help. We provide fast, local AC repair in Columbia, MO and surrounding areas, including Fulton, Boonville, and Mexico.

Schedule a Service Call Today

Call (573) 615-6659 or request AC service online. We’ll get your system cooling again — fast.