What To Do When Your AC Unit Freezes Up

It can be frustrating and annoying when the outside temperature is 100 degrees and the air conditioner keeps freezing. We rely on our air conditioners to cool us down, but that's not ideal when it's cold enough to form ice crystals.

How Does An Air Conditioner Freeze?

How Does An Air Conditioner Freeze?

When the temperature of the air is warm, its molecules are very active. When the molecules are static, the air temperature is cold. Thanks to the Joule-Thomson effect, we know that when the air in our air conditioners goes down, the molecules slow down. However, once compressed, they become active again and heat up.

The purpose of an air conditioner is to expand its refrigerant to create cool air as it exits the system. So if something goes wrong, the whole process will be disrupted and the coolant will slow down too quickly, causing ice to form.

What Causes An AC To Freeze Up?

The most common reason for a frozen air conditioner is a dirty air filter. Clogged filters impede airflow and disrupt the cooling process. Other reasons could be refrigerant leaks, kinked lines, or clogs elsewhere in the air conditioning system.

Recognizing the Signs of a Frozen AC Unit

Recognizing the Signs of a Frozen AC Unit

Recognizing the signs of a frozen AC unit is crucial in addressing the issue promptly and preventing further damage to your cooling system. A frozen AC unit not only fails to provide adequate cooling but can also lead to potential breakdowns if left unattended. Here are some key signs to help you identify if your AC unit is frozen:

1. Ice Formation on the Indoor or Outdoor Unit

One of the most obvious signs of a frozen AC unit is the presence of ice buildup on either the indoor or outdoor unit. Check the evaporator coil inside your home or the refrigerant lines leading to the outdoor unit. If you notice a layer of ice or frost, it indicates that the unit is freezing up. Keep in mind that some ice formation on the outdoor unit during colder weather is normal, but excessive or prolonged ice accumulation is a sign of a problem.

2. Lack of Cool Air or Weak Airflow from the Vents

When your AC unit freezes, it struggles to cool the air effectively, resulting in a noticeable lack of cool air or weak airflow from the vents. You may notice that the air coming out of the vents is warmer than usual or not as forceful. If you experience this issue, it is likely that ice formation is hindering the proper flow of cool air from your AC system.

3. Unusual Noises or Dripping Water

A frozen AC unit may produce unusual noises or dripping water. When ice builds up on the evaporator coil or other components, it can cause the system to vibrate or produce rattling, hissing, or bubbling sounds. Additionally, as the ice melts, you may notice water dripping or pooling around the indoor unit or along the refrigerant lines. These signs indicate that your AC unit is freezing and needs attention.

4. Increased Humidity in the Home

An unexpected increase in humidity levels inside your home can be an indication of a frozen AC unit. When an AC unit freezes, it fails to properly dehumidify the air, resulting in elevated moisture levels. You may notice a clammy or sticky feeling in the air, condensation on windows, or mold/mildew growth in certain areas. Excessive humidity can cause discomfort and potentially lead to other issues such as mold and indoor air quality problems.

5. Unresponsive Thermostat or Control Panel

A frozen AC unit can sometimes affect the functioning of the thermostat or control panel. If you notice that the thermostat is unresponsive or displaying erratic behavior, such as incorrect temperature readings or failure to adjust settings, it could be a sign of a frozen AC unit. The freezing process can disrupt the normal operation of the control system, resulting in control panel issues.

What Should I Do When My AC Freezes?

If the unit is still running but not blowing cold air, turn off the compressor but leave the fan on. This helps warm air circulate through the unit and defrost it faster. If the device does not work at all, turn everything off and check the air filter. If the filter is dirty, clean or replace it and continue to defrost.

Depending on the amount of ice present, the thawing process can take as little as one to two hours. In more severe cases, you will need to leave it on overnight. Be careful not to drip water as the ice melts, and empty the drip tray if necessary.

Preventive Measures to Avoid AC Unit Freezing

AC unit freezing can be a frustrating and inconvenient problem to deal with. Fortunately, there are several preventive measures you can take to avoid your AC unit from freezing up. By following these proactive steps, you can ensure the proper functioning and longevity of your cooling system. Here are some preventive measures to consider:

1. Changing Air Filters Regularly

One of the primary causes of AC unit freezing is dirty or clogged air filters. When air filters become blocked with dust, dirt, or debris, it restricts the airflow, leading to a drop in temperature and potential ice formation. To prevent this, make sure to regularly check and change your air filters according to the manufacturer's guidelines. Typically, filters should be replaced every one to three months, but this can vary depending on usage and environmental factors.

2. Clearing Debris Around the Outdoor Unit

The outdoor unit of your AC system requires proper airflow to function efficiently. Over time, leaves, grass, twigs, and other debris can accumulate around the unit, obstructing the airflow and causing the system to overwork and freeze. To prevent this, regularly inspect and clear any debris around the outdoor unit. Maintain a clear area of at least two feet around the unit to ensure adequate airflow.

3. Ensuring Proper Airflow with Unobstructed Vents

Blocked or closed vents can disrupt the airflow in your home and affect the performance of your AC system. To avoid AC unit freezing, ensure that all vents and registers are open and unobstructed by furniture, curtains, or other objects. Proper airflow allows the system to distribute cool air evenly and reduces the risk of ice formation.

4. Scheduling Professional AC Maintenance

Regular professional maintenance is crucial in keeping your AC unit in optimal condition and preventing freezing issues. Schedule annual or bi-annual maintenance visits with a qualified HVAC technician. During these visits, the technician will inspect and clean the system, check refrigerant levels, lubricate moving parts, and identify any potential issues before they escalate. This proactive approach can significantly reduce the chances of your AC unit freezing.

5. Checking and Maintaining Proper Refrigerant Levels

Refrigerant plays a vital role in the cooling process of your AC system. Insufficient refrigerant levels can cause the evaporator coil to freeze. It is essential to have the refrigerant levels checked and maintained by a professional technician. If there is a leak or low refrigerant levels, the technician will identify and fix the issue, ensuring the system operates efficiently and preventing freezing.

6. Avoiding Thermostat and Control Board Issues

Faulty thermostats or control boards can disrupt the normal operation of your AC system and contribute to freezing problems. Ensure that your thermostat is properly calibrated and functioning correctly. If you notice any irregularities, such as inaccurate temperature readings or unresponsive controls, contact a professional technician to diagnose and address the issue promptly.

Remember to call the pros at Bannister Plumbing & Air for all your AC repair and AC maintenance needs. It’s better to have small problems addressed now before they become larger ones.