AC Freezing Up

Common Symptoms

You might be experiencing this problem if you notice any of these signs:

• Visible ice on copper refrigerant lines
• Frost or ice on indoor evaporator coils
• Reduced or no airflow from vents
• Water leaking from indoor unit
• AC running constantly without cooling
• Hissing or bubbling sounds
• Ice on outdoor unit components
• Puddles near indoor air handler

Step-by-Step Diagnosis

Follow these steps to identify the exact cause of your problem:

1. Turn off AC immediately to prevent compressor damage
2. Inspect indoor coils for ice buildup (open access panel)
3. Check air filter - hold up to light to see if clogged
4. Verify all supply vents are open and unobstructed
5. Check outdoor unit for ice on refrigerant lines
6. Feel airflow from vents - should be strong when fan runs
7. Look for closed or blocked return air vents
8. Check thermostat fan setting (should be AUTO not ON)
9. Inspect outdoor unit for debris blocking airflow
10. Note if problem occurs on particularly hot days
11. Check if problem started after running AC continuously
12. Listen for refrigerant leak sounds (hissing, bubbling)

Most Common Causes (Ranked by Likelihood)

DIY Solutions

Step-by-Step Instructions:

1. Turn thermostat to OFF (not just higher temperature)
2. Set fan to ON to speed defrosting process
3. Replace air filter immediately if dirty
4. Open all closed supply vents throughout home
5. Remove furniture or curtains blocking vents
6. Place towels around indoor unit to catch water
7. Wait 3-4 hours for complete defrosting
8. Check drain pan and clear any standing water
9. After defrost, turn system back to COOL mode
10. Monitor for 24 hours - if it freezes again, call pro

When to Call a Professional

Don't attempt DIY repairs if you experience any of these situations:

• Unit freezes again within 48 hours after defrost
• Ice forms even with clean filter and open vents
• Hissing or bubbling sounds indicating refrigerant leak
• Weak airflow even with new filter
• Ice on outdoor refrigerant lines
• Visible oil spots on copper lines
• Blower motor sounds weak or struggling
• System is more than 10 years old

Prevention Tips

Stop this problem before it starts with these preventive measures:

• Replace air filters monthly during peak cooling season
• Keep all vents open - don't close more than 20% of vents
• Schedule professional coil cleaning every 2-3 years
• Don't set thermostat below 68°F
• Maintain 2 feet clearance around outdoor unit
• Have refrigerant levels checked annually
• Clean outdoor condenser coils yearly