What Causes an Air Conditioner to Freeze Up?
It is 87 degrees outside.
So naturally your air conditioner decides this is the perfect time to become an ice machine.
If you see ice on an AC refrigerant line or evaporator area, something is wrong.
An air-conditioning system needs the evaporator coil to be cold.
Why Does Ice Form?
The evaporator coil is designed to absorb heat from indoor air.
Under normal conditions, moisture condenses on the cold coil and drains away.
If the coil temperature falls below freezing while moisture continues collecting, ice can form.
Insufficient Airflow
The coil needs warm indoor air moving across it.
If airflow becomes restricted, the coil may become excessively cold.
Possible airflow restrictions include:
Refrigeration Problems
Improper refrigerant conditions can also contribute to coil freezing.
If refrigerant is low because of a leak, simply adding more without addressing the underlying issue is not a complete repair.
The refrigeration system needs to be diagnosed.
Blower Problems
If the indoor blower cannot move enough air, the evaporator coil may not receive the airflow it needs.
Running AC in Unusual Conditions
Cooling equipment is designed for specific operating conditions.
Running a traditional AC when outdoor temperatures are unusually low may contribute to abnormal operation unless the system is specifically designed for those conditions.
What Should You Do if the AC Is Frozen?
Continuing to run a frozen system usually does not make it magically thaw and work harder.
You may be able to leave the blower fan operating to help move room-temperature air across the coil, depending on the system and situation.
How Long Does It Take to Thaw?
That depends on how much ice has formed and indoor conditions.
Do not begin troubleshooting or service work until the ice is gone.
Ice can hide the underlying condition and make components difficult to inspect properly.
Can I Chip the Ice Off?
Evaporator coils and refrigerant tubing are easy to damage.
Sharp objects, heat guns and aggressive “DIY thawing” can turn a service call into equipment damage.
Check the Filter While You're Waiting
If the filter is severely dirty, replace it.
That may resolve one obvious airflow restriction.
Why You Should Not Ignore It
A frozen AC cannot properly cool the house.
More importantly, the conditions causing the freeze may continue stressing the system.
Repeated freezing can lead to:
Ice Is the Symptom
Air Comfort can evaluate airflow, refrigeration performance and equipment operation to identify the actual cause.
Turn Cooling Off and Let's Find Out Why It Froze
Air Comfort Heating & Air Conditioning helps homeowners throughout Anoka County, the North Metro and surrounding Minnesota communities diagnose frozen AC systems, airflow restrictions, refrigeration problems and equipment issues.
Thawing the system gets rid of the ice. Finding the cause keeps you from repeating the same problem on the next hot day.
Frozen Air Conditioner Questions
Can a dirty filter freeze my AC?
Severe airflow restriction from a dirty filter can contribute to evaporator-coil freezing.
Should I run my AC while it is frozen?
No. Turn off cooling and allow the equipment to thaw before the cause is evaluated.
Does a frozen AC automatically mean low refrigerant?
No. Refrigerant problems are one possibility, but airflow and equipment issues can also cause freezing.
