Updated at: 20-10-2022 - By: Sienna Lewis

An icy blast of air conditioning is always welcome during the sweltering summer. An air conditioning unit that freezes is a horrible thing. Systemic management of airflow, temperature and pressure are all part of the air conditioner’s operation. The refrigeration system in an air conditioner, which generates cool air, can freeze itself if any of those components malfunction. You won’t be able to use your air conditioner if it’s frozen.

In order to comprehend how this is possible, one must first grasp the basic principles of air conditioning operation.

Warm air must be blown through a coil of cold refrigerant in an air conditioner before cold air can be produced. The warm air also prevents the coils from freezing over, which is an additional benefit. Warm air from inside a building is removed via an interior coil and transported to an outdoor coil, from where it is pushed out of the building. An air conditioning unit’s evaporative cooling may have made you feel hotter than the outside temperature. As a result, the system is drawing in air from the inside and discharging the surplus heat to the exterior.

Refrigeration coils in air conditioners are maintained by using pressure to control the flow of air across the coils. The coils can get frozen if the warm air is not blown over them, or if the pressure is not maintained in any way. Many factors contribute to this. What do you think?

To begin with, it’s important to note that high humidity can exacerbate the problem of frozen pipes and pipes. This is due to the fact that the more moisture that comes into touch with the forming ice, the more ice accumulates on the wires. In fact, ice can begin to move up the compressor’s copper lines, all the way to the compressor itself.

What Causes An Air Conditioner To Freeze Up - LA Construction Heating and Air

For now, let’s examine the causes why a computer freezes up.

1. Insufficient Air Flow

This is the most typical cause of an air conditioner becoming frozen. From a malfunctioning blower motor to a problem with the air intake, this can be the result. Whatever the cause, freezing and ice accumulation can begin as soon as warm air ceases flowing over the coils.

2. Blocked Air Duct

Because your home’s air conditioning system relies on working air ducts, any problem with them — such as a collapse or blockage — can be disastrous. Even if the rest of the system is working smoothly, a lack of air movement can cause the unit to freeze.

3. Failed Blower Motor

That’s exactly what it does: blow heated air across the coils. The air movement over the coils can be impeded if it fails or has a problem, resulting in ice formation. When a blower motor fails, it might make erratic noises or even rattle.

4. Low Voltage in the Home

If you haven’t already noticed, using your air conditioner more often raises your electric bill throughout the summer. In order to keep your house cool, the device relies on a number of high-power components. A lack of airflow across the coils might be caused by a blower motor or fan failing due to insufficient voltage. Coils can freeze up as a result of this, of course.

5. Dirty Air Filters

It’s easy to overlook the fact that your air conditioner has a filter to keep the air and the unit clean from the dusty air in your home. The filter may be clogged if you haven’t taken care of this. When the filter becomes clogged, less air can get into the unit, which can cause it to freeze.

6. Dusty Coils

Using a dirty or non-existent air filter can lead to the accumulation of dust on the coils of your air conditioner. When there is a buildup of dust, it can hinder the warm air from reaching the coil. There is a risk of frostbite.

7.  Refrigerant

Problems can arise if there is not enough refrigerant in the system. After the heat from within has been expelled, the compressor in your air conditioner compresses the refrigerant in order to cool the room. The refrigerant is transformed into a gas by the combat air. As the refrigerant gets hotter, it lowers the system’s pressure. After that, it’s turned back into a liquid and directed toward the home’s blower motor.

Compressing the refrigerant to a gas occurs too early in the process when there is not enough refrigerant. This causes moisture to accumulate on the coils. Ice can build up on the coils as the process continues, and the longer it goes on, the more ice there is. It’s critical that you keep your air conditioner’s refrigerant levels in check.

What to do if I find this problem

First, switch off the thermostat while leaving the fan on if your air conditioner is blowing warm air and looks to be frozen. Allowing the coils to thaw will let the airflow to continue through the system, without it being occupied with cooling the air. If the filter is full, it’s a good idea to check and change it.

The best course of action is to call a repairman, who can determine exactly what went wrong and fix it. Keep the fan going and inspect the filter, and tell the repairman what you’ve done. Help them figure out what’s wrong with it. An air conditioner that freezes up may be serviced and you’ll be back to your cool, well-regulated comfort in no time.

Why Air Conditioners Freeze Up

AC units can freeze up for a variety of reasons. To keep the cold coil warm, air conditioners require adequate airflow. The coil needs warm air from the house to stay cold and maintain a temperature above zero degrees Fahrenheit. Without it, the condensed water can’t be discharged from the unit until the coils have froze. Check the air filter and make sure the registers are both clear and open, as dirty filters and closed registers might hinder airflow. Low refrigerant levels and poor fan operation might also result in a freeze up. A defective fan and low refrigerant levels cause the coils to become overly chilly.

Drainage issues and faulty thermostats are two common reasons of a freeze-up. Water vapor condenses into liquid outside an air conditioner during the cooling process. The drain hole will become blocked if the coils are frozen. The AC is still running, but it isn’t cooling the house adequately and is wasting a lot of energy. To defrost the coil on a window air conditioner, simply use a hairdryer. Drainpipe obstructions, such as debris and twigs, should also be checked for. Be aware that running an air conditioner with frozen coils could result in catastrophic failure. The compressor is the most expensive part of an air conditioner, so you don’t want to have to deal with repairing or replacing it. Call a trained specialist if you’re unable to fix the frozen coil problem on your own.

HVAC Repairs

At Custom Air & Plumbing, we fix a wide range of HVAC issues, including AC freeze-ups, for commercial and residential clients. The summers in Bradenton FL can be very hot, which is why we provide HVAC repair services as promptly as possible. As a matter of fact, we provide a 24-hour emergency service for our consumers. You can reach us at any time by dialing our number. A service professional will be dispatched immediately after we get your call. Our first priority is to ensure that you have a pleasant experience at home.

Our techs are the best in the business. Technicians at our company are both factory-trained and NATE-accredited. Their instruments for diagnosis, repair, and troubleshooting are state-of-the-art as well. A competent repair is guaranteed, as well as a 100% guarantee on all repairs. HVAC supplies, services, and repairs are all available through our company.

What to Do When Your Air Conditioner Freezes Up?

If you detect that your air conditioner has frozen, you should act quickly to prevent further damage. To defrost a frozen air conditioner, take these three procedures.

My Air Conditioner is Frozen! What Caused This to Happen? - Atkinson

Step 1 – Thaw Your Air Conditioner

Defrosting your air conditioner might take anywhere from one hour to up to twenty-four hours, depending on how much ice has built up.

Your thermostat should be turned off as a first step. Frozen AC coils can be detrimental to your compressor, which is one of the most expensive and vital parts of your HVAC system, especially when it’s hot outside.

Turning on the fan will aid in the thawing process by circulating warm air over the ice-covered AC coils, so speeding up the entire process.

The only exception is if you observe frost on the fan blades. However, this is going to take a while, so please be patient. Do not use a sharp object to shatter the ice, as this could cause more harm than good to your AC system.

Even a blow dryer will work to quickly defrost your air conditioner. Use a wet vacuum to remove water that has dripped outside the drain pan and into ducts and other areas. When your air conditioner is leaking water, frozen evaporator coils are the most common cause.

Step 2 – Dry Your AC

After the ice has thawed completely, turn the unit back on and let the coils to dry completely. Detach the cover from the air conditioner and allow it to air dry.

Step 3 – Find the Cause and Fix It

Your air conditioner may freeze up for a variety of reasons. Otherwise, your AC coils will keep freezing up again until you locate the source of the problem. Restart the HVAC system and set the thermostat to ‘cool mode’ once the problem has been resolved. Everything is OK if you can feel the chilly air in your room.

To find out why, we’ll look into the problem.

What Causes an Air Conditioner to Freeze Up?

It is necessary to have a basic understanding of how an air conditioner operates in order to determine what is causing it to freeze up.

The evaporator coils in your air conditioner absorb heat from the air in your house. The air is absorbed by the liquid refrigerant in the coils, which is a heat and moisture absorber. The heat is removed from the liquid before it is transported to the outside unit. The condensate drain pan situated beneath the evaporator coils also drains the surplus moisture.

Your air conditioner relies on a steady supply of warm air to function properly. It gets so cold in the refrigerant that any moisture on the coils freezes if warm air from your house doesn’t reach it.

So, problems hindering the airflow inside the air conditioning unit or issues with the refrigerant flow can result in your AC unit freezing up. Let’s explore some of the causes, along with how you can keep your air conditioner from freezing up:

1. Dirty Filters Causing a Blockage

Problems with the airflow or refrigerant movement within the air conditioning unit can cause your AC to freeze. When your air conditioner freezes, here are a few things to keep in mind:


This can easily be resolved by doing a thorough cleaning of your air filters, which should be an obvious first step. However, before reusing it, take careful to thoroughly dry it out.

Cleansing an overly-dirty filter may be preferable than replacing the filter altogether in some cases.

Every two weeks during peak season, you should clean and replace your AC filters.


Depending on how often you use it, you should tune up your air conditioner at the beginning of each season as well as every few months or so after that. Furthermore, a smart AC controller can alert you when your filter needs to be cleaned. This will ensure that your air conditioner is in perfect working order and will assist to avoid it from freezing up!

2. Incorrect Thermostat & Fan Settings

The way your air conditioner transmits heat from the inside to the outside can be influenced by reducing the temperature and fan speed.

A high-speed fan must be used in the summer months when the outside temperature is extremely high. As a result of the low fan speed, the device will have difficulty sustaining the desired temperature.

Cold refrigerant running through the unit, coupled with poor airflow, results in ice formation on the coils.


Increasing the fan speed and ensuring adequate ventilation are the most important factors in this situation. You can also adjust the thermostat settings to prevent cold refrigerant from running through the system by raising the thermostat setting.


Avoid using your air conditioner for long periods at extremely low temperatures in order to avoid freezing up your air conditioner.

3. Bad Compressor

A compressor is considered the heart of an HVAC unit and is responsible for compressing the refrigerant and removing the heat from your home.

The core of an HVAC system is the compressor, which compresses the refrigerant and removes heat from your home.

Frozen AC coils are the result of a worn-out compressor’s inability to adequately flow refrigerant. Ice forms on the coils in this condition because they remain chilly at all times and there is no condensation.


A faulty compressor is beyond repair, and it is strongly advised that you get a new one as soon as possible. Have your compressor inspected by HVAC assistance.

What Causes An Air Conditioner To Freeze Up? - Waypoint


The best way to avoid AC unit freezing up troubles is to keep up with regular HVAC maintenance.

4. Running AC on Cold Nights

There is a requirement for a steady flow of warm air around the evaporator coils to keep them from freezing over, as was previously detailed in detail.

Cooling systems are unable to circulate because the air is frozen before the refrigerant can ever reach the coils when temperatures fall low enough to cause it to become too cold for circulation.


Turn your air conditioner to fan mode and leave it running until the ice melts to avoid this problem.


Cold nights are the worst time to use your air conditioner. When the temperature dips at night, open the windows to enjoy the refreshing breeze.

A smart thermostat or an AC controller can also be programmed to shut down your unit when the temperature dips below a specified threshold.

5. Dirt and Dust Clogging up the Evaporator Coil

Was your AC serviced in the recent few months?

Unless you have a recent memory of cleaning the evaporator coils, it’s likely that dust and debris have accumulated there. It’s also possible that an old, neglected air conditioner with dirt and grime all over it will freeze its coils if used for an extended period of time.

The heat transfer between the coil and the refrigerant is impeded by the accumulation of dirt on the coil. Frozen AC coils are the result of the coils becoming too cold due to the refrigerant and not enough heat being transferred.


Run the air conditioner in fan mode for a time and allow the ice to defrost before moving on. Unless your AC coils have been fully cleaned, it is advised that you do not turn the unit on. Your evaporator coils should be cleaned using a gentle brush or cloth. However, you’ll have to wait till the ice melts before you can do this.


Keep your appliance in peak condition by having it serviced regularly! Your appliance will last longer if you take good care of it.

6. Low Refrigerant Levels Cause AC Coils to Freeze

Low refrigerant is a serious issue for air conditioners in and of itself, but it can also lead to freezing of the air conditioner. Refrigerant must expand more during the transition from liquid to gas since the refrigerant in your system is relatively low. The lower temperature within the unit might quickly freeze any moisture on the coils as a result of more expansion.

Most likely, you have a refrigerant leak or a damaged refrigerant line in this situation.


If your air conditioner has a leak or a technical problem, it’s best to call in an HVAC specialist to inspect and remedy the problem. In addition, your air conditioner’s refrigerant will be topped off to the necessary levels by the technician, assuring optimal performance.


Maintaining your air conditioner is the best defense against it being frozen. Early symptoms of refrigerant leakage can be spotted if regular maintenance is carried out, such as cracks and corrosion accumulation.

7. Clogged Drain System

In addition to keeping your home at a comfortable temperature, your HVAC system is also responsible for removing excess moisture from the air. This excess moisture can be discharged outside your home via a drainage system.

It’s also possible for water to back up into your system and freeze on the coils when the refrigerant is absorbing heat. Clogged drains are caused by an accumulation of debris and poor upkeep.


After shutting down your system, locate the drain pan. Clean it with soap and water solution after emptying it. After that, inspect the drain and thoroughly clean it with a wire brush. If it’s entirely blocked, wet/dry vacuuming may be necessary.


Keeping your air conditioner in good working order will help you avoid future problems like these. Every six months, pour a bleach and water solution down the drain to thoroughly clean and prevent the growth of mold.

8. Faulty Blower Fan Motor

Your AC unit’s blower fan is meant to distribute the air throughout your home by circulating the air. The fan spins to disperse the heated or cooled air from the device throughout your home.

When the blower fan in your air conditioner fails or malfunctions, it reduces airflow and causes the unit to freeze. The moisture on the coils can quickly freeze if the fan stops working, which can happen when there is no air flowing through the system.


Consult with an HVAC professional to have the blower fan thoroughly examined. Your fan’s spinning speed and power output will also be examined during the inspection. Repair or replacement may be necessary depending on the extent of the damage.


An annual checkup by HVAC experts can help to avoid this problem in the future.

9. Vent Blockage

Vent blockage is a common cause of AC freezing, although most homeowners aren’t even aware of it.

It’s possible that you’ve unintentionally blocked one or more of your HVAC system’s air vents. Air conditioners can freeze if they are obstructed by bulky furniture, shades, or drapes, for example. Also, keep in mind that shutting down too many vents can cause your air conditioner to freeze.

Solution & Prevention:

This is a simple problem to solve. The first thing you should do is to examine all of your vents for obstructions. Next, clear the way for the air vents by removing any obstructions in their path. Finally, ensure sure there is enough room around the vents to allow for unobstructed air flow.

You should now have all the information you need to stop your air conditioner from freezing up. As a result, it’s time to give your air conditioner a thorough cleaning as well as take care of your AC filters!