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What to Do When Your AC Unit Freezes Up

We may have hot weather, but even in Birmingham, you should know what to do when your AC unit freezes up. What? An AC freezing up in the summer? Before you call us crazy, it happens frequently. 

In this blog, we’ll review why an AC freezes even without Jack Frost around and what to do when your AC unit freezes up. 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 in Two Steps!

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 the ice 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. 

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 AC 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.

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 an AC Freezes Up 

  1. Dirty Air Filter
  2. Refrigerant Leak
  3. Airflow Obstruction
  4. Dirty Evaporator Coil

Simply put, when your air conditioner suffers from poor airflow, the evaporator coil gets too cold. This is the part that “cools” the air and without good airflow, it freezes. 

Why? Because 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. 

How to Prevent a Frozen AC Unit

Now you know what to do when your AC unit freezes up and why it does it. How to stop it from happening in the first place? Here are some preventive measures you can take to keep your HVAC system from freezing over.

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, grime and 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 AC 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.

Related blog: How a Condensate Pan Works

Need More Assistance with What to Do When Your AC Unit Freezes Up; Call Douglas!

A proactive and preventive mindset saves you money throughout the year on your energy bill and keeps your air conditioning running well. Avoid the headache of ice on your HVAC system’s evaporator coils with good airflow and regular service. 

Make it even easier with membership in one of our service plans. We offer plans at three different levels to fit any budget. So call Douglas Cooling & Heating today and schedule an HVAC maintenance call for your heating and cooling system. 

Our team serves homeowners throughout the Birmingham, Alabama area, including Bessemer, Calera, Chelsea and Helena. You’ll also find our team in Vestavia Hills, Pelham, Mountain Brook, Homewood and Hoover. 

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