What to Do If Your Power Is Out and AC Won’t Start in St. Louis

If your power is out and your air conditioner (AC) won’t start, immediately check your main breaker panel for tripped switches, verify the outage by asking neighbors, reset any tripped breakers, and confirm your thermostat and AC unit are powered on. If power returns but the AC still won’t run, schedule a qualified HVAC technician to inspect and restore your cooling system.

These steps work whether you’re in St. Louis or elsewhere.

 

Ensure Safety First

 

Working with electrical systems or HVAC equipment can be dangerous. Always:

• Keep water away from electrical panels and AC components.
• Wear rubber-soled shoes and use insulated tools if you must touch wiring.
• Never open the AC’s metal panels while it’s powered—wait until breakers are off.

 

Confirm the Power Outage

 

First, make sure your home isn’t the only one without power:

• Check if street lights are off or if neighbors’ homes have lights or appliances running.
• Look for utility company alerts on social media or call their hotline to learn about scheduled or storm-related outages.

 

Check Your Breaker Panel

 

Your home’s circuit breaker box controls electricity flow. To inspect it:

• Locate the breaker panel—often in basements, garages, or utility closets.
• Open the panel door and look for any switches in the middle position or marked “Off.”

 

Reset the AC Circuit Breaker

 

If the breaker for your AC has tripped:

• Flip the switch fully to “Off,” then firmly back to “On.”
• Listen for a click; that confirms it engaged correctly.

Wait a minute for power to reach the AC unit before testing.

 

Inspect the AC Equipment

 

After resetting breakers:

• Check the outdoor condenser (metal box) for debris, leaves, or ice blocking airflow.
• Look at the indoor air handler (usually in a basement or closet) for water leaks or frozen coils.
• Ensure the power switch on the outside unit (a small box on the wall) is also turned on.

 

Verify Thermostat Settings

 

Sometimes the thermostat loses power separately:

• Replace its batteries if it’s unpowered or blank.
• Set it to a cooling mode and a temperature 5°F below room temperature.
• Wait a few minutes to see if the AC responds.

 

Consider Backup Power

 

If outages are frequent, you can use backup solutions:

• Portable or standby generators with an automatic transfer switch can restore both lights and AC.
• Uninterruptible Power Supplies (UPS) help small electronics but aren’t sized for whole-home AC units.

Homeowners in Nashville often install generators to keep cool during summer storms.

 

Schedule Professional Inspection

 

Once the power’s back on and you’ve tried basic resets:

• If the AC hums but doesn’t start, or trips the breaker again, shut it off.
• Contact a licensed HVAC technician to check wiring, capacitors, compressors, and refrigerant levels.
• An electrician can test your home’s voltage stability and repair faulty circuits.

 

Preventive Maintenance Tips

 

Keeping your system in top shape reduces outage-related problems:

• Change or clean air filters every 1–3 months to avoid overloads.
• Trim plants and remove debris around the outdoor unit for proper airflow.
• Inspect and tighten electrical connections annually.
• Test your backup generator quarterly and replace its oil and filters as recommended.

By following these clear steps—from immediate safety checks and breaker resets to inspecting your thermostat and scheduling professional help—you’ll know exactly what to do when a power outage stops your AC from starting.