What To Do When Your AC Unit Freezes Up

air conditioner filter causing frozen ac unit

Air conditioners may be cooling systems but they are not meant to freeze up. It is not part of their design. If it happens, then the cooling system is not working as intended. It will not be able to cool down the house as well as it should. The air conditioner might even act in surprising ways. Clearly, this situation should not be allowed to continue. Read on to find out the probable reasons why this occurs, what to do when your AC unit freezes up, and the easy prevention strategies.

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Reasons Behind Frozen Air Conditioners

Below, we discuss some of the reasons why you may find ice forming on your air conditioning system.

1. Clogged Air Filters

Good airflow is essential for the proper operation of air conditioners. Among the common bottlenecks are the air filters, so that’s the first place that homeowners should investigate. If these are clogged, then there will not be enough air flowing across the evaporator coils. The coil temperature will continue to drop since no heat is being transferred over to the refrigerant. After a while, the coils will get frozen. This makes a bad situation even worse.

2. Other Airflow Obstructions

image of hvac air vent

Some homeowners are aware of the importance of good airflow. They make it a habit to replace the air filters before they get too dirty. It’s a great routine that they should continue. However, this may not be enough to prevent freezing. Airflow may also be affected by blocked registers and vents, for example, so people should check these out as part of basic troubleshooting. Furniture, curtains, indoor plants, and other objects might be too close to these air passages. Make the necessary adjustments. If freezing continues, then hire HVAC professionals to check the ductwork. There might be an issue with the installation or the design.

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3. Air Conditioner Refrigerant Leaks

image of an hvac contractor checking ac refrigerant levels

Frozen air conditioners may point to a low refrigerant level. This can happen if there are leaks along their path. Homeowners might hear a hissing sound or feel a surge of hot air coming from the AC. This problem will not go away on its own. The leaks must be sealed immediately to prevent further loss. After this, technicians must add additional refrigerant to go back to normal levels. This is not something that homeowners should tinker with because the substance is toxic. Experts are trained to handle the matter safely. They also have the right tools for the job.

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4. Dirty Air Conditioner Evaporator Coils

dirt on air conditioner coils

The fourth reason for frozen air conditioners is problematic evaporator coils. In old systems, owners may not notice the build-up of dirt over time. This layer of dust and grime will serve as a barrier between the coils and the surrounding air. It will reduce heat transfer, causing the coils to become colder than they should be. Dirt may also block the condensate lines and make the trapped water vulnerable to freezing. All of these will make the system work harder and consume more energy.

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How to Deal with a Frozen Air Conditioner

1. Thaw the Air Conditioner

Upon seeing the frozen parts of the air conditioner, you should immediately turn the unit off to prevent the problem the situation from deteriorating any further. Cutting off the power to the cooling system will stop the flow of cold refrigerant into the frozen area. The ice will melt by itself thanks to the heat of the surrounding air. However, the process may require hours to finish. If the house is getting too hot for you, then open the doors and windows to let the fresh air blow inside. You can also turn on electric fans to increase air movement. Some people use sharp objects to break the ice down but this could lead to more problems. Exercise patience for better results.

2. Dry the Air Conditioning Coils

Remember that melting the ice is just the first part of the process towards normality. The second is dealing with the inevitable wetness across the AC. This can get messy. Dry things up before using the air conditioner. Use an external fan to hasten drying or run the blowers to achieve the same goal. This may take an additional hour or so. Leave it for a while and come back for inspection. If the inside has dried up, then you can resume normal operation.


Prevention Strategies for Freezing Air Conditioners

Frozen coils can be a big headache. You want to avoid this at all cost. Regular maintenance should take care of this so make sure that you do the following:

1. Periodic HVAC Filter Replacement

image of an hvac air filter replacement

HVAC air filters are necessary for improving indoor air quality and minimizing dirt inside the system. By catching airborne particles, they prolong the life of the air conditioner and take care of the family’s health. However, their effectiveness drops over time. As they catch dirt, they get clogged up such that it becomes harder for air to pass through. Owners must intervene by replacing them with new filters. This should happen every few months as needed by the system. Conduct a quick inspection every month to monitor dirt build-up.

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2. Check Air Conditioner Refrigerant Level

The amount of refrigerant flowing across the system should remain within the ideal range. If it falls below the threshold, then performance and efficiency will be affected. This is a technical matter so let HVAC professionals handle it for you. It is part of most annual maintenance checklists so schedule yours as soon as possible. If they detect an unusual refrigerant level, then they can fix the leaks and recharge the system.

3. Remove Airflow Obstructions

image of an hvac air filter replacement

Maintenance technicians will conduct a thorough inspection to uncover airflow obstructions. They will go through all the vents. They will also check the air ducts. If they identify problem areas, then they will tell you about each one. They will explain what they need to do and how these solutions can improve the situation. Sometimes simple fixes are all that’s needed, but there could also be times when complex solutions such as ductwork modifications are necessary.

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4. Clean the Air Conditioner Evaporator Coils

Air conditioner technicians can clean up the system, including the evaporator coils. Since dirty coils can be problematic, they will see to it that dirt, dust, and debris will be gone. They will also check for clogs along the condensate line and remove those for better flow. This segment will finally work as designed.



Summer may bring scorching temperatures but air conditioners can make the season bearable. If homeowners take care of their AC, then it should serve them well for many years. Professional preventive maintenance can make it last much longer while avoiding problems such as frozen coils.

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Cost is not an issue thanks to competitive pricing guarantees. Get our annual maintenance services to increase your system’s energy efficiency and lower your monthly cooling costs. Hire us for repairs and replacements to make sure that you get a suitable solution for your budget. Call Townsend Energy today and schedule an appointment. Avail of our free in-home estimates.

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