How To Unfreeze AC Unit Fast

You do not want to have an AC unit that has frozen up. If this occurs, your indoor environment will become very uncomfortable. This is particularly common during hot days.

When your AC unit freezes up, it will be unable to cool the air inside your home to the required temperature. This means that the indoors will be pretty hot and uncomfortable. The good news is that you can quickly unfreeze your AC unit.

In this guide, we take you on a step-by-step procedure on how to go about it. We also explain a few things that you can do to prevent your AC unit from freezing up again in the future.

How to Unfreeze an AC Unit

Unfreezing your AC unit need not be a complicated process. Here is a simple procedure that you can use to complete it. It takes about 24 hours altogether to remove the ice from the components of your unit and get it back into excellent working condition.

1. Switch off the thermostat of the AC unit

This will enable you to work perfectly when unfreezing the unit. However, suppose you do not switch the thermostat off. In that case, the unit will continue sending the abnormally cool refrigerant to the outside unit, thus defeating the purpose of thawing the unit’s coils.

2. Turn on the fan

This step helps to unfreeze the surfaces of your coils fast. The fan will continuously blow warm air over the coils of the unit. This will melt the ice that may have accumulated on the surface of the coils.

3. Replace the air filter

A dirty and overused air filter can also cause your AC unit to freeze up. This is because a dirty air filter clogs the way your AC unit works. All the components of the AC unit end up straining when the air filter is dirty. Therefore, check the air filter to determine if it is dirty. If this is the case, replace it with a new one.

4. Check for other possible additional faults

Faulty thermostats, low refrigerant levels, and drainage problems are some of the most common technical faults that can cause your HVAC system to freeze. Sadly, these causes are too complicated for you to solve by yourself.

The best thing to do if you suspect that the freezing cause is any of them is to call a certified technician. Your technician will help you fix such technical issues and ensure that your unit is back in perfect condition.

Why Do AC Units Freeze Up?

Your AC can freeze up because of many reasons. Mostly, the causes are mechanical faults in one of the many components of the AC unit. Occasionally, it may occur because of low refrigerant levels inside the unit. Here are a few important causes of your AC unit freezing up.

Drainage Problems

Drainage problems occur when the coils of your air conditioner become frozen. The air conditioner functions by condensing water vapor into liquid form. When this process is interfered with because of ice forming inside the coils, your air conditioner will not drain the water properly.

This means that it will be forced to use a lot of power to cool your home sufficiently. Nevertheless, it will fail to attain the required temperature because of the resulting drainage problems.

Faulty Thermostats

Your air conditioner relies on the thermostat to ensure that it cools the home to the proper levels. If the thermostat is faulty, your air conditioner will not accurately tell when to stop the cooling process. Thus, the air conditioner may either cool your home insufficiently or excessively. If it cools your home insufficiently, this means that the home will remain relatively hot.

Low Refrigerant Levels

For your air conditioning unit to function ideally, the refrigerant must remain at the ideal level. If the refrigerant decreases drastically, the coils inside your air conditioner will become quite cold.

When the coils are pretty cold, ice will begin to form and deposit within. This will cause blockages and the resulting problems of your air conditioner failing to serve you according to your expectations.

Signs that AC Unit is Frozen

There are many signs of how your AC unit is frozen. Learning how to tell if the air conditioning unit is frozen will save you valuable time unfreezing the system. Otherwise, you may waste a lot of time troubleshooting the HVAC system when the problem is simply freezing up.

Here are a few clear signs that you should look out for to tell if your unit is frozen up.

The presence of ice on the parts of your HVAC

The presence of ice particles on any part of your HVAC is a clear sign that the system has frozen up. When your HVAC freezes up, the temperature of the refrigerant falls dramatically. Also, the inside of the coils of your system becomes very cold.

The abnormally cold temperature in the inside components of your HVAC causes ice particles to settle on the parts. Thus, if you open your HVAC and see ice deposits on some parts, take this as a clear sign that your AC has frozen up.

Warm instead of cool air coming from the air supply vents

If you put your hand over any of the air supply vents and detect that the air is warm instead of being calm, it means that your system has frozen up. When your AC unit freezes up, it fails to cool the air that it releases appropriately.

This means that the air is abnormally warm instead of being cool. In the end, the air in your room remains quite hot because the unit is unable to release cool air to reduce the ambient temperature.

Hissing sound

If you hear a strong hissing sound coming from your unit, you may have to check the unit to find out if it has frozen up. The hissing sound alone cannot be taken as a clear sign that your unit has frozen up. You may have to check for other signs, including ice deposits on parts of the unit.

How to Prevent an AC Unit from Freezing Up in the Future

You can do nothing to prevent technical faults inside the components of your AC unit from occurring. However, there are a lot of things that you can do to prevent some common causes of freezing up of the AC unit from occurring. Primarily, you can prevent this from happening by maintaining your unit well.

Here are a few tips to help you keep your AC unit in good form and prevent it from freezing up.

  • Change the furnace filter regularly. Air filters have specific periods during which they are helpful. In some cases, the filters may become clogged even before the indicated period expires. Regularly check and replace them on a timely basis.
  • Keep the coils clean. Dirty evaporator coils can cause your AC to freeze up. To prevent this from happening, keep the evaporator coils of your AC unit clean always.


Whereas some of the causes of your AC unit freezing up are technical faults, others are purely maintenance issues. You can prevent your AC unit from freezing up by ensuring that the filter and coils are always clean. Nevertheless, if freezing occurs, you can unfreeze your system using a simple procedure.

At times, you may be forced to call your technician to help resolve some complicated issues that may have caused the coils to freeze up.