My AC Is Frozen: How Long To Defrost?

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Updated May 17, 2023

Even the best air conditioners can run into maintenance issues. One such problem is a frozen AC unit. There are a variety of signs and reasons why this might happen, but regardless, it’s important to know how long a frozen air conditioner needs to de-ice. Typically, it takes approximately 1 to 4 hours to defrost an AC unit. The actual time can be influenced by the extent of ice buildup, the ambient temperature, and the size and efficiency of the AC system.

This will allow you to better plan the steps on how to tackle this issue with the expectation of how much time you’ll need.


  • Various factors can cause ice in your air conditioning unit, but the biggest is having a dirty filter that causes poor airflow or leaking refrigerant.
  • A frozen unit can lead to an overall breakdown of the internal processes, so ensure you’re doing preventative maintenance to avoid this.
  • It can take anywhere from one hour to an entire day for your air conditioning unit to thaw, depending on how iced-over the unit is.

How Long Does it Take to De-Ice an Air Conditioning Unit?

A block of ice built up in your system is not good for your air conditioning unit. In fact, this can lead to a busted AC and a desperate call to an air conditioning repair service.

Insider Tip

De-icing your AC correctly will help you avoid expensive water damage.

The defrosting process can take anywhere from an hour to an entire day, but it really depends on how much ice there is. While waiting for the air conditioning unit to thaw, replace the air filter and check for other sources of wear and tear. This will help ensure you won’t have to worry about this or other problems moving forward.

If you’re curious about the individual parts of your AC, try learning about how long an air conditioner compressor should last.

Causes of Ice Build-Up

There are a few common culprits, but the biggest issue is dirty air filters. A dirty filter suffocates your air conditioner by blocking airflow.

Another common problem is refrigerant leaks, which can cause frozen coils. If you have a refrigerant leak, you must call an AC technician right away. Refrigerant gas can be hazardous, and you don’t want to breathe it in or attempt to fix this issue yourself.


Keep an eye on your condensate drain as your AC thaws, or it might overflow.

Learning how a window air conditioner works will help you understand these systems more thoroughly. If you have a wall-mounted unit, you should instead learn how a wall-mounted air conditioner works.

STAT: The turnover for the sanitation, heating, ventilation, and air conditioning (HVAC) industry in Germany has been rising steadily during the last decade, growing by over 17 billion euros between 2012 and 2022. (source)

How Long Does an Air Conditioner Need to De-Ice FAQs

Should I call a repair service to de-icing my AC?

That depends on how comfortable you are working with fixing this type of problem. If you have no HVAC experience, it might be better to call an HVAC technician to do it for you.

How do I clean a dirty evaporator coil?

You can make a mixture of detergent and warm water, and spray it on your coils. From there, use a soft brush to wipe away any dirt and debris that has collected here.

What can I do to ensure proper airflow in my air conditioning unit?

There are a few things that you can do to encourage proper airflow in your AC, including:

  • Cleaning the entire unit regularly
  • Keeping the blower fan in good condition
  • Replacing clogged filters quickly

What are the signs that my blower fan is malfunctioning?

The first sign that you have a bad blower motor is poor airflow. Fan motor issues can cause repercussions across your entire AC unit, so ensure you take care of this problem quickly.
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