ROOT CAUSES

Why Your AC Isn't Cooling

Nine times out of ten it's one of these. If you are experiencing an AC not cooling in Atlanta, the humidity and long cooling season wear out capacitors, coils and refrigerant charge faster than the national average.

Step 01

Identify Symptoms

Recognize common signs like warm air, strange noises, or water leaks on our symptoms guide.

Step 02

Repair or Replace

Evaluate whether repairing components or replacing your AC unit is the best path forward.

Step 03

Estimate Costs

Get clear pricing insights for DIY repairs versus professional HVAC technician services.

Diagnostic Index

The 10 causes behind almost every AC failure

Identify your system symptoms quickly. We break down the most frequent failures to help you decide on the right fix.

Low Refrigerant

Pro Required

Symptoms it causes:

  • Warm air blowing from vents
  • Hissing noise near evaporator coils
  • Ice on refrigerant copper lines

How to spot it:

Look for ice formation or frost buildup on the outdoor unit's brass service valves.

Repair cost:

$220 – $750 (Atlanta avg.)

Bad Capacitor

Pro Required

Symptoms it causes:

  • Outdoor unit hums but fan won't spin
  • Unit clicks repeatedly on startup
  • Hard starting compressor

How to spot it:

The run capacitor inside the electrical panel appears swollen, bulged, or is leaking fluid.

Repair cost:

$150 – $350 (Atlanta avg.)

Dirty Condenser Coil

DIY

Symptoms it causes:

  • Reduced cooling efficiency
  • High monthly energy bills
  • System frequent short-cycling

How to spot it:

Outdoor unit metal fins are visibly coated with grass clippings, pollen, mud, or debris.

Repair cost:

$0 (DIY clean) – $200 (Pro clean)

Bad Compressor

Pro Required

Symptoms it causes:

  • Outdoor unit fails to start
  • Loud metallic grinding or clanking sound
  • Tripped main electrical breaker

How to spot it:

Outdoor cabinet is hot to the touch with no air movement or compressor motor vibration.

Repair cost:

$1,200 – $2,800 (Atlanta avg.)

Clogged Air Filter

DIY

Symptoms it causes:

  • Weak airflow from supply vents
  • Warm room temperatures
  • Ice on indoor evaporator coil

How to spot it:

Remove the air return intake filter — if it is gray, dense, and dust-coated, airflow is choked.

Repair cost:

$15 – $40 (DIY replacement)

Faulty Thermostat

DIY

Symptoms it causes:

  • Thermostat screen is blank
  • AC won't trigger cooling cycle
  • Incorrect temperature readings

How to spot it:

Replace batteries or set cooling target 5° lower than ambient with zero response from the unit.

Repair cost:

$25 (DIY battery) – $250 (Pro replacement)

Blocked Condensate Drain

DIY

Symptoms it causes:

  • Water pooling around indoor unit
  • Drain pan overflowing
  • Automatic AC emergency shut-off

How to spot it:

Standing water in the emergency overflow pan or safety float switch triggered at air handler.

Repair cost:

$0 (DIY flush) – $180 (Pro clear)

Failed Blower Motor

Pro Required

Symptoms it causes:

  • No air exiting supply vents
  • Burning smell near indoor air handler
  • Loud squealing noise

How to spot it:

Thermostat calls for cool, outdoor compressor runs, but zero airflow comes through house registers.

Repair cost:

$400 – $900 (Atlanta avg.)

Tripped Breaker / Electrical Fault

DIY

Symptoms it causes:

  • Total loss of AC power
  • Blank thermostat
  • Zero response from indoor and outdoor units

How to spot it:

Check main house electrical panel for double-pole AC breakers resting in center or OFF position.

Repair cost:

$0 (Reset breaker) – $220 (Pro wiring repair)

Leaky Ductwork

Pro Required

Symptoms it causes:

  • Uneven cooling between rooms
  • Excessive dust in living spaces
  • Unusually high power bills

How to spot it:

Inspect accessible attic or crawlspace duct runs for detached joints, tears, or peeling tape.

Repair cost:

$350 – $1,500 (Atlanta avg.)

§ DIAGNOSTIC INDEX

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