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How to Stop AC from Freezing Up – Quick Fix with Preventive Measures

Air Conditioners are one of the best ways to survive through a scorching day. However, you might sometimes see a layer of ice on top of your outdoor AC system. While it’s weird enough for ice to form in the summer, this problem isn’t rare and happens to many people. There are even times when you might not even be able to see the ice layer on your outdoor AC system. So what is it with ACs becoming frozen? And how do I keep my air conditioner from freezing up? Those are two questions that we’ll go ahead and answer today.

Why Does My AC Unit Freeze Up?

Before we learn what exactly causes ACs to freeze, we need to know how their systems work. The start point of an AC system is the evaporator coils. These coils are filled with intensely cold refrigerants. Refrigerants, however, are not exactly in their gaseous forms while stored. Hence, when your AC evaporator coils start working, the refrigerant within it will need warm air to pass across to cool the air around. Passing warm air will ensure that your coils do not freeze and the air is cooled.

The evaporator coil has two components – indoor and outdoor coils. The job of the indoor coil is to remove all heat from the air of a room (using the refrigerant) and pass it to the outdoor coil. So, in simple terms, these coils are throwing out the extra heat that your indoor air contains.

If you have ever put your hand around your outdoor AC unit at any time, you may have felt hot air. This air can be even hotter than the average temperature outside. The reason behind such hot air is outdoor, which is responsible for taking this heated air and pushing it outside to your outdoor AC component.

If, for any reason, air cannot travel over the evaporator coils, then you have a problem. In such scenarios, the coils become cold (due to the constant exposure to the refrigerant and no warm air) to such an extent that they’ll eventually freeze up. Even a malfunction in the pressure of the refrigerant can cause the same to occur.

What Causes Air Conditioner to Freeze Up?

We’ll go a bit deeper about the ways and causes of your AC unit that keeps freezing up in hot or cold weather.

1. Dust

Dust within indoor air is probably the leading reason ACs freeze up. The refrigerant inside your AC is usually quite damp. If dusty air ever passes through it, it forms a thick blanket.

The dust now causes the cold air to stay inside the AC system rather than outside. This insulates the evaporator coils and creates an area with freezing air. Further exposure to more dust can lead to ice formation too.

2. Air Supply

A problem with the air supply can be the culprit for a frozen AC unit inside or outside. If the blower motor inside your AC doesn’t work correctly, you’ll face an issue of lack of air supply to the evaporator coils. As mentioned earlier, these coils require a certain amount of warm air to stay away from freezing. If the blower does not blow warm air quickly enough, your coils will begin to freeze.

The motor blower might also face exterior issues. An excellent example of this is a low voltage supply. ACs require a good amount of electricity to function correctly, and if there isn’t an adequate amount of it, the motor blower won’t work as fast as it should.

If you have moisture in the surrounding air, matters only get worse. When high humidity is present, it won’t take long for the cold air to settle and form into ice. This ice will stick to your AC’s coils and insulate them, leaving no chance for any warm air to touch the coils.

How Do I Keep My Air Conditioner from Freezing Up?

If your air conditioner has already frozen inside or outside, we’ll show a couple of methods that you can use to fix it.

Step 1: Thaw out the ice

The first order of business is to switch off the AC and prevent any potential harm to the system.

You could turn the thermostat off while keeping the system on to turn off the compressor and keep the fans on. This may thaw out the ice quicker. However, the best thing would be not to perform such a thing unless you’re sure of the problem. The reason for saying this is that freezing can cause permanent damage to your air conditioning unit if not appropriately treated.

So, your most reliable option is switching off the AC completely to ensure no damage to the compressor. Note that the compressor is the most valuable and priced component of an AC. If broken, you’ll be left no option other than to pay a fortune for repairs or even replacements. Regardless of the weather, wait an entire day to ensure all ice is melted down to the very last bit.

Now, you might be tempted to break the ice quickly by inserting a sharp object (knife). However, this action will be no short of breaking a component inside the unit. So keep yourself away from the urge of hurrying the thawing process and be patient enough to wait an entire day.

Step 2: Drying

Once you’ve waited an entire day to melt the ice, the next step is drying the evaporator coils. From here you’ll have to rely on a good sunny day.

Let your AC coils rest in the heat or at an everyday place in your house that can help them dry. Feel free to use a paper towel if you want to. Now, set the system back correctly. After this, turn the AC back on and only allow the blower (or fan) to operate through your thermostat.

This process can vary depending on the type of thermostat you have. Once the blowers start working, your evaporator coils should dry out completely in around 5-15 minutes. Once the coils are dried up, your AC should work normally and cool indoors.

Of course, if you feel hesitant about doing these steps all by yourself, don’t shy away from calling the repair service. If you’re not sure of a component or area of the air conditioning unit, bringing the mechanics is your most suitable choice.

How Can You Protect an AC from Icing Up?

Now that we’ve made it clear on how to fix your AC when froze up, go through this guide to avoid this from happening in the future.

In most cases, the air conditioners freeze up due to the low maintenance of the HVAC (Heating, Ventilation, and Air Conditioning) system. Once these are checked regularly, you can easily prevent your AC from freezing. Besides, if you often do not inspect the air conditioner units, you will have such issues.

However, there’s not just one factor contributing to A/C freezing up, and thus, to avoid ice formation do as follows.

1. Clean the Air Filter

One of the primary reasons for a low airflow in the AC unit is that the air filter is dirty. This indirectly lowers the airflow towards the evaporator coils, which is essential to keep the AC coil from freezing up as constant humid air blows on it. Moreover, it puts pressure on other parts of the AC unit. Therefore, it’s best to make sure you clean the air filter monthly to avoid freezing the evaporator coil.

2. Check the Refrigerant Levels

Another way the evaporator coil can become cooler is if there’s a leak in the AC components or the refrigerant wasn’t installed correctly. But, again, you’ll require a professional HVAC technician to solve the problem in such scenarios.

3. Optimal Fan Speed

Apart from this, it’s also possible that the fan speed has reduced or isn’t sufficient enough to heat the evaporator coil enough to prevent it from freezing. So, contact a professional that will increase the fan speed to an optimal level to avoid the freezing of the coil.

4. Examine the Condensate Drain Every Week

Lastly, examine the condensate drainage system every week. This is extremely important as most water vapor condenses to water within the AC in humid weather conditions, but that’s not a problem as this water will drain out.

However, if any blockage or disruption stops the water from draining, it will freeze onto the evaporator coil; thereby, the ice will congest the drain. To avoid this, check upon the AC drain, especially during the summer seasons, make sure the water drips into the pan and pours out from the floor drain.


To conclude, there are various aspects that the AC might end up getting frozen. The most straightforward methods to prevent this are switching off the AC when not in use, cleaning the AC components, and having regular maintenance checkups of your air conditioner.

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