AC Running But Not Cooling? Here’s What’s Wrong

When your air conditioning is running but not cooling your home, it can be frustrating—especially during Ohio’s hottest months. If your AC is blowing warm air or struggling to maintain a comfortable temperature, there are a few key reasons why this might be happening.

Why Is Your AC Running But Not Cooling?

1. Dirty or Clogged Air Filter

Your AC’s air filter traps dust, dirt, and debris to keep the system clean and improve indoor air quality. However, when it gets clogged, it restricts airflow, reducing efficiency and making it harder to cool your home. A clogged filter can even cause the system to overheat or freeze up.

Quick Fix: Replace your air filter every 1-3 months to maintain efficiency. If your AC isn’t cooling properly, check the filter first.

2. Thermostat Issues

Your thermostat controls your entire cooling system. If it’s set incorrectly or malfunctioning, your AC may run but not cool effectively. 

How can you tell if the thermostat is bad?

• Incorrect settings (ensure it’s set to “Cool” mode)
• Low battery power
• Misplacement (if installed near heat sources, it may read incorrectly)

Quick Fix: Adjust the thermostat, replace batteries, or consider upgrading to a smart thermostat for better accuracy.

3. Refrigerant Leak

Refrigerant is essential for cooling, as it absorbs and removes heat from your home. A leak can cause your AC to blow warm air, work harder, and spike energy bills.

How Can You Tell If There’s a Refrigerant Leak?

• Ice buildup on refrigerant lines
• Hissing or bubbling noises
• Weak airflow from vents
• Higher-than-usual electricity bills

Solution: Refrigerant leaks require professional repair. If you suspect a leak, call an HVAC technician immediately.

4. Blocked or Dirty Condenser Coils

Your outdoor AC unit (condenser) releases heat from inside your home. If the coils are dirty or blocked by debris, your system can’t dissipate heat efficiently.

Quick Fix: Check the outdoor unit for leaves, dirt, or obstructions. Gently clean the coils with a hose (but avoid high-pressure water) or call a professional for maintenance.

5. Frozen Evaporator Coils

The evaporator coils inside your AC absorb heat. If they freeze, airflow is restricted, and your AC won’t cool properly.

What Causes Frozen Coils?

• Dirty air filter
• Low refrigerant levels
• Blocked airflow
• Running the AC at very low temperatures for extended periods

Solution: Turn off your AC and let the coils thaw completely before restarting. If freezing happens frequently, schedule an HVAC inspection.

6. Leaky or Poorly Insulated Ductwork

Cool air travels through your home via ductwork. If your ducts have leaks or poor insulation, cool air may escape before reaching your rooms.

Signs of Leaky Ducts:

• Uneven cooling (some rooms cooler than others)
• Higher energy bills
• Dust buildup near vents

Solution: Have a professional inspect and seal your ductwork for better efficiency.

DIY Troubleshooting Before Calling a Professional

Before scheduling AC repair, try these quick fixes:

✅ Replace the air filter if it’s dirty ✅ Check the thermostat settings and batteries ✅ Inspect and clean the outdoor condenser unit ✅ Ensure vents and registers aren’t blocked by furniture or drapes

If none of these steps solve the issue, it’s time to call a professional.

When to Call an HVAC Technician

Some AC issues require expert repair. Call a technician if:

• Your AC keeps turning on and off rapidly (short cycling)
• You see ice buildup on the evaporator coils
• Your unit leaks water or refrigerant
• The system is over 10-15 years old and losing efficiency

Prevent Future AC Problems with Regular Maintenance

Routine AC maintenance helps prevent cooling issues and extends system lifespan. A professional tune-up includes:

• Deep cleaning the coils and fan blades
• Checking refrigerant levels
• Inspecting electrical components
• Testing the thermostat and controls
• Ensuring proper airflow

Annual maintenance can save you from expensive repairs and lower energy bills.

Schedule Your AC Repair with Heart of Ohio

If your AC is running but not cooling, don’t sweat it—Heart of Ohio’s expert HVAC technicians can diagnose and fix the issue quickly.

📞 Call us or contact us today to schedule a fast AC repair and stay cool all summer long!