AC Not Cooling? 7 Reasons Your Savannah AC Is Blowing Warm Air

By Bryan Donaldson, Owner, On Time Air. 25+ years of HVAC experience in Savannah, GA.

The system’s running. You can hear it. But what’s coming out of the vents is room temperature or worse, and it’s the first genuinely hot week of May.

Work through these in order. Three of them you can fix yourself in under ten minutes, and we get called out for those more often than you’d think.

1. The Thermostat Is Set Wrong

Start here. It’s not condescending, it’s just the most common cause and the cheapest to rule out.

Check the fan setting. If your fan is set to ON instead of AUTO, the blower runs continuously, including between cooling cycles. Air keeps coming out of the vents even when the compressor is off, and that air is room temperature. People interpret that as the AC failing.

Set it to AUTO. Now air only moves when the system is actually cooling.

Check the mode. COOL, not HEAT, not FAN ONLY. If someone else in the house adjusted it, or a smart thermostat updated overnight and reset, this happens.

Check the batteries. A thermostat with dying batteries can hold a display while failing to send a call for cooling.

Check the schedule. Programmable thermostats revert to schedule after a manual change unless you hold the setting. Your 4pm setback may be doing exactly what you told it to in March.

2. The Air Filter Is Clogged

A filter choked with dust and pollen restricts airflow across the evaporator coil. Less air across the coil means less heat removed, weak airflow at the vents, and eventually a frozen coil.

After a Savannah spring, filters load up fast. If you haven’t changed yours since pollen season, pull it out and look at it against a light.

If you can’t see light through it, that’s very likely your problem. Replace it and give the system an hour.

3. The Outdoor Unit Isn’t Running

Go outside and look at the condenser. The fan on top should be spinning and you should hear the compressor.

If it’s completely silent and still:

• Check the breaker in your electrical panel. AC circuits usually take two adjacent slots. A tripped breaker may not look obviously off; push it fully to OFF, then back to ON.
• Check the outdoor disconnect box, the small box on the wall near the condenser. It may have been pulled for service and not reseated.
• If the breaker trips again immediately, stop. Do not keep resetting it. Repeated tripping means an electrical fault and resetting it repeatedly is a fire risk. Call us.

If you hear a hum but the fan isn’t turning, that’s most often a failed capacitor. It’s the most common repair we do and it runs roughly $150 to $350. Turn the system off at the thermostat until it’s repaired, because a compressor trying to start without a working capacitor can damage itself.

Do not try to spin the fan with a stick. I know that trick is all over the internet. People get hurt doing it and it doesn’t fix anything.

4. The Evaporator Coil Is Frozen

Open the panel or look at the refrigerant lines where they enter the air handler. If you see ice on the coil or a thick frost coating on the larger copper line, the coil is frozen.

A frozen coil cannot transfer heat, so the air coming out is warm even though the system is straining.

What to do: Turn the cooling OFF at the thermostat and set the fan to ON. Running the blower without cooling thaws the ice much faster than shutting everything down. Expect one to three hours. Put towels down, because there will be water.

Once it’s thawed, replace the filter and check that no supply vents are closed. If it freezes again, the underlying cause is either airflow restriction or low refrigerant, and it needs a technician. We wrote a fuller explanation in our post on why AC systems freeze up in Savannah humidity.

5. Refrigerant Is Low

Air conditioners don’t consume refrigerant. It’s a sealed system. If you’re low, you have a leak. Full stop.

Signs: weak cooling that’s gotten gradually worse over weeks, ice on the refrigerant lines, a hissing or bubbling sound, or the system running constantly without reaching setpoint.

This isn’t a DIY repair, and I’d steer you away from the recharge cans sold at auto parts stores. Adding refrigerant without finding the leak means you’re paying to leak it into the atmosphere again, and overcharging a system damages the compressor.

The right fix is locating the leak, repairing it, and then recharging to the manufacturer’s specified weight.

6. The Condenser Coil Is Filthy

Your outdoor unit sheds heat by moving air across a coil. When that coil is packed with pollen, grass clippings, and dirt, it can’t dump heat, so the refrigerant returns to the house still warm.

This is a big one in Savannah after pine pollen season. Go look at yours. If the fins are matted rather than lightly dusty, that’s restricting it.

You can rinse it. Kill power at the disconnect first. Use a garden hose, never a pressure washer, and spray gently. Also clear at least two feet of vegetation around the unit.

If it’s genuinely caked, it needs a chemical cleaning by a technician to get between the fins properly.

7. Ductwork Problems

If some rooms are cool and others aren’t, the equipment may be fine and the delivery system may not be.

Common causes: disconnected duct sections in the attic or crawlspace, crushed flex duct, significant leakage at joints, or a failed zone damper.

Attic ductwork is the frequent offender here. A Savannah attic runs 130 degrees in summer, so a duct that’s come loose is blowing your cooled air into the attic while pulling superheated air into the return side.

You can sometimes spot this yourself by looking for obviously disconnected or crushed ducts. Anything beyond that needs diagnosis.

When to Stop and Call

Call right away, without troubleshooting further, if:

• The breaker trips repeatedly
• You smell burning or see scorching at the disconnect or panel
• There’s a loud grinding or screeching from either unit
• Someone in the home is elderly, very young, or has a cardiac or respiratory condition and the house is climbing past 80 degrees
• You’ve been through this list and it’s still not cooling

That last one matters. Running a system that’s struggling, especially one that’s been freezing, can turn a capacitor replacement into a compressor replacement.

Frequently Asked Questions

Why is my AC running but not cooling? The most frequent causes are a thermostat fan set to ON instead of AUTO, a clogged filter, a failed capacitor in the outdoor unit, a frozen evaporator coil, or low refrigerant from a leak. Work through them in that order.

Can I add refrigerant to my AC myself? No. Refrigerant handling requires EPA certification, and low refrigerant always means a leak that needs repair. Adding refrigerant without fixing the leak wastes money and overcharging damages the compressor.

How long does it take a frozen AC coil to thaw? One to three hours with the cooling off and the fan set to ON. Turning the whole system off takes considerably longer.

Why does my AC blow cold then warm? Often a freezing coil that thaws and refreezes, or a system short cycling. Both usually trace to restricted airflow or low refrigerant.

Is it bad to run my AC if it’s not cooling? Yes. A system that’s freezing or low on refrigerant can suffer compressor damage from continued operation. Shut it off until it’s diagnosed.

Still Warm? We’ll Come Find It

If you’ve worked the list and your house still isn’t cooling, we’ll diagnose it properly and give you a written price before any work starts.

Serving Savannah, Pooler, Richmond Hill, Rincon, Tybee Island, Wilmington Island, and all of Chatham, Effingham, and Bryan counties.

Call On Time Air at 912-210-4901 or request service online.

Related: Emergency AC repair in Savannah, AC repair costs, and air conditioning services.