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Why Does My AC Freeze Up?

We may have hot weather, but even in Birmingham, you should know what to do when your AC unit freezes up. It’s so hot outside, how is it possible that my AC has ice on it? Before you call us crazy, it happens frequently.

In this blog, the team at Douglas Cooling & Heating will review why an AC freezes even on the hottest days of the year, and what you should do when you notice this happening. We’ll also include tips to prevent frozen HVAC coils. With our tips, you may avoid an AC repair visit but if you need us, a friendly Douglas Cooling & Heating HVAC tech is ready to help!

What to Do When Your AC Unit Freezes Up in the Summer

Luckily, it only takes 2 steps to restore your air conditioning system back to normal after it freezes. Follow along to help your system.

Step One: Thaw It Out

Turn off your AC unit at the electrical breaker and let the ice thaw. Be advised, it could take a whole day for a frozen air conditioner to completely thaw. Pick a day when you plan to spend time elsewhere, just be mindful of any pets in the house and the forecast. If a day’s rest is impractical, turn the AC off but leave the blower running which will continue to move warm air over the coils and help them thaw.

Make every effort to avoid using the AC while the evaporator coils are frozen. Running the AC with frozen coils strains the AC compressor. The air conditioning system compressor is the most expensive component in your air conditioning unit. The strain may damage this valuable part and set you up for an unplanned expense.

Finally, don’t listen to advice that you should break up the ice with a heavy object or sharp tool. This easily damages components and creates new problems. Instead, you can try to use a hair dryer to help with the melting process.

Step Two: Dry the Coils

Once the ice is gone, dry the evaporator coils. If off, restore the power to your system and turn the blower on. Set the thermostat to only run the blower or fan. This circulates air around and through the coils to dry them quickly.

Once the coils are dry, your system should operate normally. It’s important, however, to prevent it from happening again, even if you now know what to do when your AC unit freezes up.

Why Does My AC Freeze Up?

Air conditioners freeze all the time, but it can be a major inconvenience, not to mention expensive to fix. Many homeowners may not know what causes this issue to arise and how to prevent it. Here are some of the common causes of air conditioner freezes.

Dirty Air Filter

The first common cause of frozen air conditioners is due to restricted airflow. This happens when the air filter is clogged or dirty, and the air conditioner cannot efficiently remove heat from your home. When restricted airflow occurs, the evaporator coils become too cold, leading to the formation of ice on the coils. This problem could be resolved by simply replacing the air filter. Air filters should be changed on a regular basis, usually between every 30-90 days.

Dirty Evaporator Coil

Your AC’s evaporator coil is really just a cluster of refrigerant coils. As the refrigerant passes through, the chemical reaches temperatures as low as 10 – 20 degrees Fahrenheit. During normal operation, warm, unconditioned air passes over the coils. The existing warmth in your household’s air prevents ice or frost formation. If, however, there’s a lack of warm air moving across the evaporator coils, they ice over. The ice even travels along the refrigerant lines. As humid air, which we have a lot of here in Birmingham, meets the coils and condenses, it freezes even faster.

Mechanical Issues

Another reason for air conditioner freezing could be related to mechanical issues, such as a malfunctioning blower fan, which causes the air conditioner to work incorrectly, leading to ice buildup. When these components do not work properly, airflow is restricted and the coils become too cold.

Refrigerant Leak

Air conditioner refrigerant leaks are another common cause of freezing. Refrigerant is the substance that cools the air in your AC. When there is not enough refrigerant in the air conditioning system, it will cycle too often, causing a rapid decrease in temperature and increasing the chances of the evaporator coils freezing. When your refrigerant levels are low, your system has to work harder to cool your home, which can cause the coils to become too cold and freeze up. If your system continues to run with low refrigerant levels, it can cause permanent damage to the compressor, resulting in a costly repair. This problem can only be fixed by a professional AC repair technician.

Using Your AC When It’s Too Cold Outside

Lastly, if the temperature outside is below 60 degrees, and your AC’s temperature is set below 68 degrees, this can cause the evaporator coils to freeze as there is not enough warm air in the house for the AC to sufficiently cool. In this case, it is best to just turn off the air conditioner and wait for the temperature to improve before turning it back on.

Get Help for Frozen AC Issues

If you are asking why my AC freeze up, you might be tempted to try and fix the issue yourself. Beyond changing your air filter and making sure your system is only used when it’s warm enough outside, you should leave the repairs to the professionals. Freezing coils are often a symptom of a larger problem that requires the expertise of a licensed HVAC technician. Calling a professional is not only the safest option; it’s also more cost-effective in the long run.

It’s important to note that while frozen coils are a visible symptom of an issue, the underlying cause may not always be as apparent. A licensed technician has the training and expertise to inspect all of your system components including your blower fan, condensate pan, refrigerant coils, and more to identify the root cause. They will be able to provide an effective solution that will prevent the problem from happening in the future. Working with a professional HVAC company will ultimately save you time and money in the long run. Don’t let your AC continue to freeze up; call Douglas Cooling & Heating for air conditioning system repairs today.

How to Prevent a Frozen AC Unit

Now you know what to do when your AC unit freezes up and the common causes. How can you stop it from happening in the first place? We have some preventative tips to stop ac freezing from happening again.

1. Change Your Air Filter

A dirty air filter is a top cause of a frozen HVAC system. The air filter cleans the air circulated into your home. Over time, it clogs with dirt, pollen, dust, and other allergens. This restricts the airflow and the HVAC coils freeze.

Typically, we recommend you check your filter monthly. Change it as needed. For most folks, this is one to every three months. Filter changes vary based on factors, such as:

  • The type of filter you have
  • Presence of children or pets in the home
  • The season and if you live in a high-pollen count area
  • Whether a household member smokes
  • A household member lives with asthma, allergies, COPD, or congestive heart conditions
  • If you frequently run your system

During regular HVAC maintenance, Douglas Cooling & Heating professionals inspect your filter and will change it for you if a new one is available.

2. Schedule Regular Maintenance to Check Coolant Levels

As part of a seasonal tune-up, a professional HVAC contractor performs a comprehensive inspection. This includes checking coolant levels and charging if necessary.

Think you might have a coolant leak? There are a couple of signs. For example, does your AC blow hot air? Do you hear a hissing? Douglas HVAC techs use measuring instruments to check levels as well. Avoid handling coolant chemicals, because they can be toxic. Leave it to the professionals if possible.

3. Get an Airflow Inspection

Obstructed airflow is a major reason heating and cooling systems malfunction or function inefficiently. Similar to a clogged filter, blocked vent returns and registers prevent adequate airflow.

This causes your system to work harder without a way to release the cooled or heated air. Are vents and registers clear from any obstructions? Your problem may be poorly designed or installed ductwork. In some cases, the ductwork is installed well but the wrong size for your house or the capacity.

Call Douglas Cooling & Heating for HVAC maintenance. Our trained professionals inspect your ductwork and offer redesign solutions, if necessary. If there is a clog, like nesting material or other signs of pests, we clear obstructions blocking proper airflow.

4. Clean Evaporator Coils

The condensate lines drain excess moisture from your HVAC system. If there’s a clog in the line, the water becomes stuck and the excess water freezes. With frozen water in your lines, you could be left with frozen HVAC coils as well.

Over time, evaporator coils attract dust, hair, and grime can form a clog. If there is moisture trapped inside the clog, the moisture freezes and the coils freeze as well. Frozen coils restrict airflow. This causes your system to struggle or not work at all.

The best prevention for frozen HVAC coils is to schedule preventive maintenance. Douglas Cooling & Heating checks the evaporator coils and the rest of your unit’s lines during an AC tune-up.

Save money, avoid AC repairs, breakdowns, and a frozen HVAC system in the future with routine air conditioning service.

Call Douglas For Air Conditioner Repairs in Birmingham, AL

A proactive and preventive mindset saves you money throughout the year on your energy bill and keeps your air conditioning running well. If you ever notice your AC unit freezing up, follow our tips to thaw your system yourself, and then call Douglas Cooling & Heating for an AC inspection or repairs.

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