4 Reasons Your Air Conditioner Is Frozen & How to Fix It

As bizarre as it may sound, ice can accumulate on the outside of an air conditioning unit in Florida. This is never a good sign. It can be alarming to discover a block of ice in your AC. Luckily, it’s not as scary as it looks.

Air conditioners freezing over is actually a common problem. Sometimes a frozen AC requires professional help, but you may be able to repair it yourself depending on the cause of the freeze.

What to Do When There’s Ice Buildup on Your AC Unit

If you notice ice buildup on your air conditioner, you can protect your AC by turning your system off or switching the unit to a fan-only setting. Use the fan only option if your system has that, it will help the evaporator coils dry off faster.

The only way to remove ice from your air conditioner is to shut it off and allow the ice time to melt. When your air conditioner is on, it is pumping freon through the evaporator coils, which means they’re going to stay cold and the ice won’t melt. Without the coils operating, the ice should melt.

It should take about 24 hours for the ice to melt, but it could be longer if your unit is covered in a solid block of ice.

While the ice is melting, you’ll want to keep an eye on your condensate drip pan. If your thermostat does not have a fan only option, you should take a towel or paper towels and dry off the evaporator coils and fins. If you have the fan only option, you shouldn’t have to do anything other than leaving it blowing for 24 to 48 hours.

What Causes Your Air Conditioner to Freeze Over?

When your air conditioner is continually running, water collects on your AC’s evaporator coils. The water is supposed to drip off the coils and dry, however, if the water stays on the cold coils for too long it will turn into ice.

When your air conditioning system is running at full capacity, moisture contained in the air can rapidly freeze and condense on the grill, cooling coils, condensate lines, and other parts. When ice buildup occurs, you may notice that your air conditioner is only blowing warm air. If there is ice on the outside unit, it may also be accumulating on the coils inside the air handler.

Below are things that can impede the process outlined above and cause your air conditioner to freeze.

1. Poor Airflow

Check to see whether dirt or debris is blocking airflow around the unit.

If not, check and replace your air filters. Clogged filters can cause the unit to work harder to produce the same level of comfort.

Dirty air filters can cause your air conditioner to freeze by decreasing the amount of air going through your system. Your AC is designed to work with a specific balance of airflow and pressure. Just the right amount of water has to collect on the fins, for the perfect amount of air to pass over it, so the drops drip just right into the condensation drip pan.

One slight change to this equation, such as less air passing over the fins because less air can get through your clogged filter, can completely throw off your AC’s balance. When there isn’t enough air passing over the fins, the water droplets hang out on the metal for a little bit too long and turn into frost.

In addition to clogged air filters, the evaporator fan may be spinning too slowly or not at all. In either case, the fan motor will need to be serviced. Other causes of poor airflow include clogged or leaky ductwork, which requires duct cleaning and sealing.

2. Low Refrigerant Levels

Another common cause of freezing is the refrigerant level being too low. A common sign that this is your problem is that your air conditioner’s refrigerant line is covered in ice.

Freon is another name for the refrigerant used to cool the evaporator coils in your AC. As a chemical, it is very sensitive and can change states of matter very quickly. For example, freon could be a liquid that is boiling or not boiling at the same temperature, depending on pressure. The pressure inside of your AC is determined by airflow.

If any part from your compressor to your inside unit is obstructing airflow, or changing the temperature of the system, then this delicate balance can be thrown off. During normal operation of your AC system, your condenser holds the freon as gas. Your compressor makes this freon super hot, at 100 degrees Fahrenheit the chemical turns from a gas into a liquid. When anything is extremely hot, it also has a high pressure. So your AC system shoots this high pressure, liquid hot freon towards your house. Before the hot liquid freon reaches the inside part of your AC system, it’s pushed through a special device that makes it incredibly cold, around 20 degrees Fahrenheit, very quickly.

When refrigerant levels are too low, that means that the pressure inside of the tubes the freon travels through will also be too low. When the pressure is low, the freon is colder than usual when it gets to the cooling stage just before being run through your evaporator coils. This makes the evaporator coils extra cold and can cause the water to freeze. Measuring the pressure and the level of refrigerant in your system takes some special tools, so it’s best to leave that to the professionals.

You need a qualified licensed HVAC technician to check the level and add more refrigerant if necessary. It is important that you have the entire unit checked for leaks to prevent a loss of refrigerant in the future.

3. Fan Problems

Another common reason for AC freezes can be an issue with your fan. That might sound concerning, but don’t worry. Fans can get dinged or worn out through normal use and operation. Sometimes a larger object travels through your system and it can knock the AC fan out of balance.

An HVAC professional will be able to tell you if your fan is running properly, and get it back to spinning level.

4. Dirty Evaporator Coils

Your air conditioner filters all kinds of gross stuff out of your home’s air, such as hair, pet dander, dust, dirt, and mold. But your AC filter doesn’t catch everything, so over time the evaporator coils inside your system can become caked in layers of grime. You can call a friendly Blair’s Air licensed HVAC professional to do a deep cleaning, which you might need to do depending on how bad the dirt is. Otherwise, you can try to remove some of the gunk yourself.

First, be sure to turn the air conditioner OFF. Some people recommend switching the breaker to the system off as well. You can use a soft brush like a toilet brush or a toothbrush to scrub buildup off of your evaporator coils. You could also use a paper towel, and gently try to loosen the grime on the fins with your hand. Be careful not to use too much pressure, you don’t want to bend any of the metal fins or coils.

The professionals at Blair’s Air use special chemicals to loosen more intense buildup, but if you have minor grime you can try to use some water to loosen it, then scrub it off with a soft brush or a paper towel.

Call Blair’s Air to Repair Your AC Unit

If you have tried these remedies and your AC is still freezing, you may need the help of a professional. Luckily these are not major, or expensive repairs, but they are generally a little too complicated for the DIYer to handle.

When you see ice on your air conditioning unit or need HVAC maintenance and repairs in the Tampa Bay area, let Blair’s Air Conditioning and Heating be your first choice. We are a family-owned business that pledges prompt customer service at a fair price.

Whether you need to schedule a preventive tune-up or are experiencing an emergency, we service all brands with a 100 percent satisfaction guarantee. Call us today to schedule an appointment to get the answers to your heating and air conditioning problems.

Call 727-592-8479 to schedule your appointment.