Updated at: 13-04-2023 - By: Sienna Lewis

When your AC freezes up, do you know what it means? If you don’t, don’t worry; you will after reading this post. Many would agree that having a cold air conditioner is preferable, but others disagree. However, the inverse is true.

Controlling the airflow, pressure, and temperature in a room is how air conditioners function. If any of these are out of whack, the machine won’t work properly.

If the Freon system that chills the air overheats and freezes, it won’t be able to cool the room any further. Even if the air conditioner is frozen solid, it will still emit warm air. In the worst case, it won’t even produce any air flow.

How Does An Air Conditioner Make The Air Colder?

The refrigerant-filled coil is the central part of an air conditioner. If you want the air conditioning to work, you need to provide warm air for the refrigerant. In addition to keeping the air cool, this prevents the coils from freezing over in cold weather.

The refrigerant will carry it from the indoor coils to the outdoor coil, effectively removing it from the interior of the home. Here, the heat is released into the atmosphere.

This is why the outdoor unit emits air that is hotter than the ambient air temperature. This is because air conditioning removes heat from the indoor air and releases it outside.

This occurs as the system regulates pressure in the refrigerant loop. However, it will eventually freeze if warm air is not being blown to the coils or if the pressure in the coils is incorrect.

If the AC freezes up, the problem is probably connected to the pressure or the airflow, or both.

How Moisture Affects The AC Unit?

Extreme humidity in the room can exacerbate the effects of freezing temperatures. It’s difficult for warm air to reach the coils when ice has formed on them and the coil itself acts as insulation.

The iciness of the room increases as the humidity rises. It will make its way throughout the AC, covering the entire inside, and even making its way up the copper pipes to the compressor outside.

What Does It Mean When The Air Conditioner Freezes Up?

When your air conditioner freezes up, what does that mean for you?

The most common causes of an air conditioner freezing up are listed below.

#1. Insufficient airflow

Lack of adequate airflow is a common cause of your unit freezing up. While this could have been caused by a problem with the air intake or the blower motor, there are other possible sources.

This would prevent warm air from reaching the coils while the compressor was running to cool the room. This problem will only get worse if nothing is done to fix it.

#2. Collapsed duct

Because of the ducts, air can move freely throughout your home. But if something is blocking this, the air cannot flow properly.

Collapsed air ducts can cause the air conditioner to freeze up even if everything else is functioning normally because there is not enough warm air to keep the coils at their optimal temperature.

#3. Blower motor malfunction

The importance of the blower motor in an HVAC system cannot be overstated. In a short amount of time, air flow onto the coils will cease if either the blower motor or the run capacitator fails.

As soon as the fan is turned off, the coils in the AC unit will begin to freeze. When your AC’s blower motor fails, you’ll likely notice a rattling noise.

#4. Low voltage

That the device is underpowered is one possible explanation. Air conditioners are a major consumer of electricity because their motors and other parts require it to function.

Furthermore, freezing can occur if the compressor is on but the blower or fan motor is underpowered.

#5. Low on Freon

The amount of refrigerant in an air conditioner is crucial for maintaining the correct amount of pressure. While releasing the collected warm air, the compressor compresses the refrigerant.

Liquid refrigerant will turn to gas when exposed to that much heat. As a result, temperature and pressure will rise and fall respectively. Once the liquid state is restored, the unit’s pressure will force it onto the blower fan and into the house.

On the other hand, if there isn’t enough refrigerant, the compressor will cycle too quickly. Moisture will condense on the coils at that time and freeze, making them inoperable.

As this continues, the ice formation will accelerate until the entire container is frozen solid. As was previously mentioned, it could also make its way towards the copper plumbing. Accordingly, it is crucial to keep the appropriate amount of refrigerant in the air conditioner at all times.

How can you tell if you might be facing a freezing problem?

When in doubt, look at the supply registers. Is it a comfortable temperature? In that case, it’s likely due to frozen evaporator coils. Check for ice by opening the cover. Remember that the absence of ice is not proof that you are not experiencing freezing conditions. However, if you find ice, you can be sure that your air conditioner is frozen.

Understanding the Joule-Thomson effect:

Let’s talk briefly about the inner workings of your AC before we dive into the potential causes of a freeze-up. To begin, know that temperature is the molecule’s energy level. Molecular motion and high energy levels account for the sensation of heat in the air. Low-energy molecules make up cold air, so the converse is also true. As a result, the Joule-Thomson Effect shows that the air in our air conditioners will cool down when it isn’t compressed, as the air will expand and the molecules will slow down. The molecules become excited and warm up when compressed.

The goal of an air conditioner is to remove the hot air from inside your home by expanding the refrigerant inside the evaporator coil and causing it to cool before releasing it into the air. However, if the air conditioner breaks down, the entire process is thrown off. As a result, the refrigerant cools below freezing and freezes over in the evaporator coil.

The question then becomes, what can be done to ensure that the cooling equation doesn’t go horribly wrong? There are typically three primary factors that lead to an air conditioner freezing up. If you know what to look for, you can prevent the need for an AC freeze-up before it happens. In addition, we’ve included solutions for each potential source, so even if your air conditioner breaks down, you won’t be without hope for long. If you take good care of your air conditioner, it will last longer, use less energy, and reduce the likelihood that you’ll get annoyed by it.

Blocked air flow causes freezing up:

Maintaining a steady airflow prevents condensation on the cooling system’s coils, which is essential for keeping air conditioners operational. If you want to keep your home’s air conditioner running smoothly, you should make sure your air filters don’t get too dirty and clogged up. The air circulation in your home is impeded. Altering air filters is a simple and inexpensive way to improve air quality. Problems with airflow and other issues can be avoided by keeping your air conditioner well-maintained. Furthermore, according to the US Department of Energy, a 5-15% increase in efficiency can be achieved by simply changing the filter in your HVAC system.

How to fix it:

Aside from the fact that your AC is currently broken, you also found out that your air filters were clogged. Most likely, there is something blocking the air ducts. The first step is to defrost the air conditioner by turning it off. Turn on the fan alone for about an hour after it has thawed for an appropriate amount of time (between one and three hours). Now is a good time to swap out the filter that cleans the air in your home. In case you’re curious about how often and when you should swap out your air conditioner’s filters, you can read up on the subject here. After that, your air conditioner should function normally again.

Mechanical problems or refrigerant leaks?

There are many moving parts in an air conditioner, and any one of them has the potential to become jammed, broken, or clogged. Things can leak, fans can stop spinning, filters can get clogged, and refrigerant lines can get kinked. The pressure drops as a result of any of these factors, allowing the refrigerant to expand beyond safe limits and become dangerously cold. Maintaining a consistent temperature throughout your device also requires refrigerant. Insufficient refrigerant is another common cause of freezing. Some of these issues can be resolved more quickly and cheaply than others. Any repair for a coolant leak is likely to be a band-aid solution at best. An upgrade to a new machine might be worthwhile at this point.

How to fix it:

A quick fix for the AC freezing over requires more than just reading this article. Hiring a professional with experience working with refrigerants is recommended for these sorts of issues. Although refrigerants can be used safely in the house, they should be handled by a trained professional. Call an HVAC service and have a technician take a look if you think a leak or a mechanical issue could be to blame for your air conditioner’s current state of disrepair. Having a professional HVAC technician perform tune-ups on your air conditioner on a regular basis can help prevent unexpected breakdowns.

Cool summer nights can cause your AC to freeze:

The optimal operating range for an air conditioner is determined by its manufacturer. In the summer, an air conditioner can get out of whack if the nighttime temperature drops below what is considered to be the optimal threshold.

Here’s some more details on swapping out the filter in your air conditioner.

How to fix it:

A programmable thermostat can prevent this by turning off the air conditioner when the temperature drops below 60 degrees. Keep an eye on the nightly temperatures if you don’t have a programmable thermometer and can’t predict if it will drop below 60 degrees. Therefore, if you want to enjoy the pleasant summer breeze, you should turn off the air conditioning and open the windows.

How Does An Air Conditioning Unit Work?

That’s not how air conditioning units work at all. There is a common misconception that air conditioning works by pumping cool air into a building. The heat is instead dissipated externally. Super, huh? Intended allusion. The refrigerant is a chemical that connects the evaporator coil, the compressor, the condenser, and the third and final station of an air conditioner in a closed loop.

Station 1:

The evaporator coil is exposed to air that has been blown over it after being sucked into the return vent and filtered. The cold refrigerant absorbs the heat and changes phase from liquid to gas. Now that it’s been cooled, the air is recirculated throughout the house to whatever rooms the thermostat, or you, have designated.

Station 2:

The gaseous refrigerant is compressed even further outside the house by the compressor, increasing its temperature to dangerous levels.

Station 3:

At the final stage, the condenser, the extremely hot vapor refrigerant is released and the heat is absorbed by the surrounding air. Instantaneous cooling causes the refrigerant to condense from gas to liquid. The liquid refrigerant has been cooled to its proper temperature and is ready to be sent back to station 1.

Is Your AC Freezing Up? Here Are The Signs:

Your air conditioner freezing up on a hot day is, as you probably guessed, not normal.

There is no need for alarm if this occurs. A little bit of investigation usually reveals the answer to the problem. However, a more serious issue may arise if the AC unit is left frozen for an extended period of time.

To begin, how do you determine if your air conditioner has frozen up?

Now, obviously, if your refrigerant line-set pipe is covered in ice, you have a problem. To determine if your AC line has frozen, just look where it connects the outdoor unit to the exterior wall of your home.

A frozen evaporator coil is another possible problem. Not as simple to verify, this. In order to inspect the indoor unit, you will need to open a panel. If you lack handyman skills, DO NOT attempt this. If not, contact a qualified HVAC technician, such asHVAC Systems by SuperTechor you risk breaking something.

There are other signs that your air conditioner has frozen than just seeing the components.

Your air conditioner has frozen up in other, less obvious ways, too:

  • The air conditioner is not recycling cool air into the home.
  • Surface condensation has developed on the indoor unit.
  • Outside of the condensate drain, condensation has formed.

Why Is My Air Conditioner Freezing Up?

The answer is straightforward: there is almost no air circulation.

The refrigerant will not change into a warm gas if there is not enough warm air flowing through the evaporator coil to transfer the heat. Instead, freezing occurs in the evaporator coil or the line carrying the refrigerant.

No bueno.

The issue is caused by inadequate ventilation, which can occur for a variety of reasons.

When your air conditioner freezes up, it’s usually because of one of these common causes of reduced airflow:

Clogged Air Filters

As dirt builds up on the filter, it prevents the circulation of warm air within the house. The air conditioner freezes up the next thing you know. Filters should be changed regularly. This article will teach you how to change your filters properly.

The supply and return vents in your home are blocked or closed in an effort to conserve energy, which can result in your air conditioner freezing up. This is caused by the blocking of the vents by furniture or curtains. Mind your step.

Clogged Condensate Lines 

The evaporator coil takes in heat and moisture from the air at the same time. Condensate water from your air conditioner’s cooling system is directed away from the frosty fluid via a drainage line. Water can freeze near the evaporator coil if the drain line is clogged.

Damaged Blower Fan

By doing so, warm air is directed toward the coils. If the air conditioner’s blower fan is broken and isn’t blowing air, or isn’t blowing enough air, the evaporator coil will freeze and the air conditioner will stop working.

Dirty Coil

If dirt accumulates on the evaporator coil, airflow is impeded, and the coil freezes. In your home, dust is transported through the air ducts. Your filter does a good job of picking up most of it. The coil will get dirty over time and will need to be cleaned. Having a professional perform checkups on a regular basis is crucial for this reason.

Low Refrigerant Level

When the pressure inside the compressor increases, the temperature of the refrigerant also rises. Loss of refrigerant causes the air conditioner to work less efficiently. Reduced pressure from low refrigerant levels freezes your air conditioning line.

Collapsed Air Ducts

They allow air to flow through an air conditioning system. A collapsed air duct will prevent air from flowing properly, which can cause a number of problems, including the air conditioner freezing up.

If Your AC Is Frozen, Try These Fixes First Before Calling An HVAC Professional 

Oops, looks like your air conditioner has frozen up. What now?

Read this before you call for assistance. It’s possible you’ll end up spending less time (and thus money) overall.

First Things First

Use the thermostat to turn off the air conditioning system. The cooling effect is halted. Toggle the fan switch on now. The mode is on, and not automatic. The defrosting process can be accelerated by directing warm air onto the coil.

We must now wait. Allow some time for the evaporator coil or refrigerant line to thaw out if it has frozen. In the worst-case scenario, this could take a full day.

The compressor should not be exposed to the frozen refrigerant. Obviously, that’s not a good thing. The compressor was designed specifically to handle hot vapor. They also don’t come cheap.

Second, Check For And Replace Your Dirty Air Filter

Reduced airflow can be caused by as little as a dust particle.

You should replace your air filter if it looks dirty. Also, remember to swap it out for a new filter that has been cleaned. You don’t want the coil to get dirty from airborne particles. Your air conditioner would freeze up if you did this.

Third, Inspect Your Vents

Check both sides for obstacles and remove them if you find any. Ignoring the possibility of a closed supply vent in a forgotten nook, you should check all of the rooms for closed vents.

Last, It’s Time To Turn The HVAC System On Again.

Continue normal operation while keeping a close eye on it. Turn it off but keep the fan running if ice forms again; the heat will help melt it. Then, get in touch with an HVAC professional.

Preventing problems like an AC line from freezing over is, of course, preferable to fixing them once they have occurred.

How Do I Keep My Air Conditioner From Freezing Up?

As we’ve already discussed, your air conditioner will freeze up if anything gets in the way of its normal airflow.

Changing the filters on your air conditioner on a regular basis is one of the best ways to keep it from freezing up in the middle of the night. Depending on the filter’s construction, the number of people living in the home, and the presence of pets, this could be anywhere from four to twelve times annually.

Establish a schedule for routine inspections and repairs next. In the spring, before the heat of summer sets in, have your air conditioner checked by a professional. Regular maintenance of your air conditioner can save you money in the long run by avoiding issues like frozen coils and increasing the lifespan of your HVAC unit.

The technician will inspect the air filters, coils, refrigerant level, drain, and blower fan to ensure they are free of debris and are turning at the correct speeds and rotations. Discover the many upsides of having your air conditioner serviced.

Last but not least, a HVAC technician can check the efficiency of your air ducts. When your air ductwork system is intricate and inconvenient to access, this can be a challenge. Air ducts can be blocked in numerous ways (detailed in our blog post on air balance). If you check your ducts in the spring and fall, you can head off an expensive problem in the future.

How to Prevent Your Air Conditioner From Freezing Up

Clean and Change the Filters Regularly

A filter in your air conditioner prevents contaminated air from passing over the coils. The filter serves a dual purpose: it prevents buildup of frost inside your system by trapping debris like dust and pollen, and it helps keep the air inside your unit clean.

Airborne particles can pass through a filter if it is too dirty. Over time, the coils will become so caked with dirt and dust that they won’t function properly. The temperature drop will be too severe, leading to the unit freezing up.

You can avoid this by regularly replacing your air filters. Stick to the filter replacement schedule recommended by your unit’s manufacturer to avoid freezing and other issues.

Inspect the Condensate Drain Regularly

When the air in your home passes over the condenser, your air conditioner will remove some of the humidity and transform it into water. The water is collected for use in cooling the air, and the excess is directed out the back of the unit. But if the water can’t get out, it will just keep going around and around the coils. If water gets on the coils, it will freeze and cause the appliance to stop functioning.

In this case, investigate why the appliance is not draining the water properly. Take off the top and the filter and have a look inside. Remove any obstructions, such as dirt and dust, to restore water flow. If the appliance’s interior is spotless, angling it ever-so-slightly backward can improve water drainage.

Have the Refrigerant Checked

A lack of refrigerator fluid or an incorrect charge could cause your air conditioner to freeze up. This could indicate that a joint or fitting is too loose, allowing water to leak out, or that two components are rubbing against one another, causing a leak.

The best course of action in such a situation is to get in touch with a professional HVAC technician for an inspection and maintenance. To avoid future issues with leaking and freezing, they can essentially refill the fluid, fix any broken or loose joints and fittings, and perform proper maintenance.

AC Units Are Designed to Work in Specific Temperature Ranges

It’s tempting for Floridians to turn on the air conditioner even when the weather outside is mild. A number of factors, including a malfunctioning air vent, an excessive number of guests, or even just some playful tinkering on the part of young children with the thermostat, can lead to uncomfortable indoor temperatures even if the weather outside is mild.

Attempting to turn on your air conditioner when the temperature outside is below 60 degrees can cause it to freeze up. Air conditioners can be damaged by freezing condenser coils if used in temperatures below 60 degrees Fahrenheit.

To avoid this, you can use other methods to cool your home, such as opening windows (during the day) or turning on a fan, even if the outdoor temperature is low.

What to Do When Your AC Freezes

When your air conditioner freezes up, here’s what you can do right away:

  • To protect the compressor and save on utility costs, turn off the air conditioner’s main power supply.
  • The condensate drain should be inspected to make sure it is not clogged while waiting for the ice to melt.
  • You could try opening the ductwork and sucking the water out with a wet/dry shop vacuum.
  • You can hasten the melting process by directing a blow dryer at the evaporator coils. Alternately, you can speed up the de-icing process by turning on the air conditioner’s fan without activating the compressor.
  • If you have a window air conditioner, tilt it back so the melted ice can drain out the back. If water is collecting inside the unit, it can be drained out the exterior condensate drain hole by clearing it.
  • Now that the drain pan is free of ice and empty, you can turn on the air conditioner. The cooling process in your home should begin instantly.

How to Keep Your AC Unit Running Smoothly

Freezing issues can be avoided with regular maintenance and cleaning. Keep the unit free of dust and other debris by replacing the filters regularly and having it serviced as needed. In this way, the coils won’t freeze up just when you need them.

Summing it up:

A frozen air conditioner is a common and frustrating issue for homeowners. However, with regular servicing and tune-ups, you can avoid the issues that lead to a frozen air conditioner. The frequency with which you perform tune-ups and swap out your air filters can greatly reduce the likelihood of breakdowns, blockages, and leaks in your mechanical systems. You can save money on your energy bill and extend the life of your air conditioner by hiring a professional HVAC service, such as Petro Home Services, to perform an annual AC Tune-up and taking advantage of a Maintenance Service Plan.