Why Is My Air Conditioner Frozen? 7 Troubleshooting Tips

May 18, 2011


It’s a sweltering day, but your air conditioning system isn’t cooling your home as it should. You go to check the AC unit and find it covered in ice

This problem can happen anytime, but it’s especially bizarre when it occurs during hot summer days. You're not alone if you’re wondering why your air conditioner is frozen. This issue is more common than you might think and typically involves the evaporator coil, which transfers heat from inside to outside your home. 

At A.J. Perri, we understand how frustrating it can be when your air conditioner isn’t working correctly. Our licensed and insured team is here to help you identify the causes of a frozen air conditioning system and provide effective solutions to get your system back up and running.

If you live in New Jersey and need help with your air conditioning unit, don’t hesitate to call your local HVAC provider. We’re committed to keeping your home cool and comfortable all summer. 

How Can You Tell if Your AC Unit Is Frozen?

Recognizing a frozen air conditioning system isn’t always straightforward, but some common signs include:

  • Reduced airflow

  • Warm air coming from the vents

  • Water leakage around the indoor unit

  • Visible ice on the AC unit

Ultimately, ice on any part of the unit is the clearest sign of AC freezing.

If you suspect a frozen AC, turn it off immediately to prevent further damage and schedule service with A.J. Perri to diagnose and fix the issue in your New Jersey home. 

Why Is My Air Conditioner Frozen? 7 Potential Causes

A variety of issues can cause air conditioner freezing. Understanding the common causes can help you troubleshoot the problem and prevent it from happening again. Here’s a look at the primary reasons an AC unit might freeze up.

1. Inadequate Airflow

Anything that restricts the airflow over the evaporator coil can disrupt the balance of your system and cause it to freeze. Blocked vents and obstructions in the ductwork are a couple of culprits that can seriously obstruct airflow.

2. Dirty Air Filter

A dirty air filter is another common cause of restricted airflow, causing the evaporator coil to get too cold and freeze. To prevent this, regularly check and replace your air filter based on your usage and manufacturer recommendations. A clean filter helps prevent freezing and improves your AC unit’s overall efficiency and lifespan.

3. Damaged Blower Fan

A damaged or malfunctioning blower fan can also reduce airflow, leading to a frozen AC unit. Common signs of a damaged blower fan include strange noises, weak airflow, or no airflow. If you suspect an issue with the blower fan, it’s essential to get it inspected and repaired or replaced by a professional.  

4. Blocked Condensate Line

The condensate line drains the moisture the evaporator coil removes from the air. If this line becomes blocked, the backed-up water can freeze around the evaporator coil. Dirt, algae, or other debris can cause this blockage.

In some cases, a vacuum can help clear the blockage, but scheduling service with an HVAC technician is generally your best bet.

5. Dirty Evaporator Coil

Dirt and debris on the evaporator coil can impede heat transfer, causing the coil to freeze. The evaporator coil must be clean to absorb heat from the air effectively. Cleaning the coil regularly ensures efficient operation and helps prevent freezing.

6. Insufficient Refrigerant or Refrigerant Leak

Refrigerant leaks or low refrigerant levels can make the evaporator coil too cold and allow moisture in the air to freeze and accumulate. If you suspect a refrigerant leak in New Jersey, contact us so we can check and refill the refrigerant for you.

7. Temperature-Related Causes

A faulty thermostat or thermostat that is set too low can cause an air conditioner to run constantly, which can eventually drop the temperature of the condenser below freezing. 

Additionally, most outdoor units do not function well in temperatures below 60°F. If your nighttime temperatures are too low, the system will not operate properly, and freeze-ups can occur.

How Do You Fix a Frozen Air Conditioner?

Fixing a frozen air conditioner involves several crucial steps to ensure your system returns to optimal performance:

  1. Turn off the system: Shut off your air conditioning system to stop further ice buildup and let it defrost.

  2. Clean or replace filters: Dirty air filters restrict airflow, which can cause an AC unit to freeze. Clean or replace any dirty filters and remove any visible dirt or obstructions.

  3. Check for blockages: Open all registers completely and ensure furniture or draperies are not blocking them. Then inspect the condensate line and coils for blockages that might impede the system’s function and clean components as needed.

  4. Schedule professional service: New Jersey residents can call A.J. Perri to inspect your system and ensure there’s no refrigerant leak or damage to your equipment. If you let the AC continue to run after the coil freezes up, you’re wasting money and risking damage to the compressor, the most expensive part of the air conditioner.

Will Turning Off the AC Unfreeze It?

Turning off your air conditioning system will allow it to defrost. This is the first step you should take when you notice your AC is frozen. Keep the system off for several hours to let the ice melt naturally. However, the ice will likely come back if you do not address the underlying issue.

How Long Does It Take for an AC to Unfreeze?

The time it takes for an AC to unfreeze can vary based on the extent of the ice buildup. Typically, it takes anywhere from one to three hours for the ice to completely melt. During this time, ensure the area around the AC unit is well-ventilated to facilitate the melting process.

Count on A.J. Perri to Fix a Frozen Air Conditioner and Prevent Further Issues

Regular maintenance on your air conditioning system helps you avoid many of the problems that can lead to a frozen system. During regular maintenance, our professionals will clean or replace your filters, check and level your thermostat, ensure the refrigerant is properly charged, and inspect coils for any signs of dirt or damage. These steps help maintain optimal airflow and efficient operation, reducing the risk of your system freezing.

If you need help with a frozen AC unit at your New Jersey home, call your local HVAC contractor or schedule service online. And if it’s been a while since you had an AC inspection, don’t wait for a problem to arise—schedule regular maintenance with A.J. Perri to keep your air conditioning system in top condition.

Be sure to check out our current specials, learn about our warranty and guarantees, and explore our financing options to help you save more on upgrades, repairs, and more.

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Last Updated: December 03, 2024