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How Do I Keep My Air Conditioning From Freezing Up?

A house's kitchen

You might not think your AC can freeze when it’s hot outside. But, it’s a more common problem than you think and can happen even on the hottest days. The best way to prevent it is to maintain your AC unit well. If your AC is already freezing up, there are ways to troubleshoot the problem. The best solution is to contact an AC specialist who can have your unit running smoothly again.

What Causes Air Conditioners to Freeze Up and How to Prevent It

Before answering the question, “How do I keep my air conditioning from freezing up?” it’s helpful to know more about how ACs function. They work by expanding the refrigerant in the evaporator coil, cooling down the air that passes through and releasing cold air into your home. It also removes the hot and humid air, helping you feel more comfortable. But if there’s something out of order inside your unit, it can disrupt the entire cooling process.

The evaporator coil can malfunction and cool the refrigerant too much. That will cause the AC to fall below freezing temperature and ice over. How can you prevent the cooling system from going haywire? Here are the three most common causes and what to do about them.

Blocked Airflow

Proper airflow is crucial within an AC system. If something is blocking the airflow, humidity can accumulate on the coils and freeze up. The best way to prevent this is by regularly cleaning or replacing your AC’s air filter. Dirt and debris can collect on it over time and restrict airflow, so it’s helpful to know how often to change the air filter in your house. It’s best to change the air filter every three months. Not only will this prevent problems from happening, but it will also improve your AC’s efficiency. Fortunately, air filters are affordable and easy to install.

Another way to encourage good airflow is by keeping the vents open. Many homeowners choose to close one or two to try and lower their electricity bill, but that can do more harm than good. This hampers airflow and increases the chances of your AC icing over.

Mechanical and Refrigerant Issues

AC units have various moving parts, and any one of them can develop problems and affect the entire system. The fan can stop moving, the refrigerant lines can become misaligned and the air filter can get clogged.

These issues can cause the pressure inside the AC system to drop. In turn, the refrigerant will get too cold and cause the AC to freeze. The refrigerant also plays a vital role in regulating the AC’s temperature. Low levels of refrigerant or leaks are common causes of freezing.

You can prevent mechanical problems by keeping the air filter, coils and fan clean. Clear away any debris that could be hampering their performance. As for refrigerant issues, an AC professional can help keep them away through regular tune-ups. Never attempt to handle refrigerant yourself. Contact a professional AC technician near you for assistance.

Temperature Drop

It may be hot and humid in the daytime, but the temperature can drop at night. When that happens, it will be harder for your AC to cope. The AC functions its best within a specific temperature range. When it becomes colder than that, it can throw off your AC and cause it to ice over.

Installing a programmable thermostat can prevent this issue. It will automatically turn off the AC when the temperature dips below 60 degrees. But if you don’t want to spend money on an additional device, you can check the forecast every night before bed. On cold nights, set the AC’s timer for a few hours. That way, it won’t be running all night and ice over.

You can also schedule an AC specialist to come over and diagnose your AC unit. The technician can perform a comprehensive system check to ensure your AC can handle temperature drops.

What to Do If Your AC Freezes Up

If you think your AC has frozen but don’t see any ice, check if you can feel air coming out of the supply registers. If there’s little to no airflow or your AC is not cooling enough, that should confirm your suspicions. Here’s what you should do if you have a frozen AC.

Turn Off the Unit

The first step is to locate your electrical breaker and cut off the AC’s power. Never run the unit while the evaporator coils are frozen because that will strain the compressor. It’s the most important and expensive part of the AC, and pushing it past its limits can lead to a costly problem. Turning off the AC as you solve the issue will also save you money.

Let the Ice Thaw

The next step is to wait until the ice thaws. This process might take a while, even if it’s hot outside. Resist the urge to chip away at the ice with a tool or heavy object because that can damage the AC’s fragile parts. Instead, you can use a blow dryer on the evaporator coils to speed things up.

Dry the Evaporator Coils

The final step is to let your AC’s evaporator coils dry. Once all the ice has melted, pat the evaporator coils with paper towels or leave them outside in the sun. You can also turn on the unit’s fan to speed up the drying process. It will help circulate the air through the coils and dry them faster. Once all the moisture is gone, your AC should be ready to run normally again.

Knowing how to fix a frozen AC is a helpful skill for homeowners. But the best solution is to contact an AC repair professional. The technician will inspect the unit, address all issues and help it run efficiently.

A white kitchen in a home

Will Turning on the Heat Unfreeze the AC?

It might seem like a good idea to turn on the heat when your AC is frozen. After all, ice melts when you expose it to heat. But running the AC while it’s iced over will only damage the compressor. And that’s the last thing you want to do because it’s not cheap to replace it. There are better ways to go about the problem, including the following solutions.

Natural Method

The natural way to solve the problem of a frozen AC is to let it thaw naturally. Turn the unit off and wait for the ice on the evaporator coils to melt. However, this method usually takes an entire day, and not everyone can go without the AC for that long.

Fan Mode

A much faster method is to turn on the AC’s fan-only mode. The warm air should melt the ice in one to two hours. Note that the refrigerant shouldn’t be flowing, nor should the compressor be running.

Hair Dryer

If you want an even faster way to melt the ice, it’s time to whip out your hair dryer. It can significantly increase the airflow running through the evaporator coils and raise the air’s temperature. However, you must be careful not to let the hair dryer get too hot or close to the evaporator coils. Introducing high heat to anything frozen can cause it to crack. Put your hair dryer on low and keep it at least 10 inches away from the evaporator coils.

An AC unit

Where Is the AC Drain Pan?

Homeowners should know where the AC drain pan is and how to keep it free of blockages and damage. It is located under the cold evaporator coils, catching the condensation as warm air flows through. To inspect the drain pan, turn off the unit and remove the access panel. Grab a flashlight and look closely at the drain pan and the drain line that connects to it.

If water is backing up, that means there‚Äôs a clog somewhere. See whether there is any visible debris and pull it out. Slowly pour a steady stream of water down the drain line and observe how the water drains. If it is still backing up, there’s a more severe clog further down the line. It is best to contact an AC specialist who can unblock the drain system.

The Bottom Line

If you’re asking, “How do I keep my air conditioning from freezing up?” the best way is to schedule air conditioning preventative maintenance done by professionals. AC specialists ensure all parts are running as they should and that the airflow and pressure are at the proper levels. They will come to your home to ensure your AC is working well.

ABC Can Keep Your AC Working Efficiently

Dealing with AC issues requires lots of technical know-how. Instead of trying to figure it out yourself, contact ABC Home & Commercial Services. Our professionals can efficiently diagnose and repair your AC problem.

Tom Riggs

Tom Riggs is the Division Manager for Mechanical Services, overseeing sales and operations for HVAC, Plumbing, Electrical, Appliance Repair and Water Quality for all ABC Austin branches. He joined ABC in 2014. Before ABC, he was an HVAC Service Technician, HVAC Comfort Advisor/Sales and Operations Manager. Tom attended Universal Technical Institute. He's an avid outdoorsman and enjoys country living with his wife and two sons.

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