How Long Does It Take To Thaw A Frozen Air Conditioner? (Unfreezing)

If you have a frozen AC unit, you will have to unfreeze it before you can start using it again. How long does it take for an AC to unfreeze? We will look into how long does it take to thaw a frozen air conditioner naturally, and with quicker unfreezing methods.

Note: You must not run the air conditioner before all the ice is gone. If you do, you might damage the all-important compressor, and compressor replacement costs almost as much as a new AC unit.

When we talk about how long does it take to thaw a frozen air conditioner we are basically talking about how long does it take for the ice, accumulated on the indoor evaporator coils, to melt completely.

how long should you wait for an air conditioner to be unfrozen

As we have mentioned in this article about how to unfreeze an AC unit fast, there are 4 methods of how to thaw a frozen air conditioner. Natural AC defrosting can take a day or more, but with speeding the thawing process, it can take less than 1 hour to thaw a frozen air conditioner.

Let’s first look at how long should it take to unfreeze an AC unit if you just leave it at room temperature. Afterward, we will look at how to speed up the process by using an AC fan or a hair dryer:

How Long Does It Take For An AC To Unfreeze Naturally?

If you shut off the unit, the air conditioner will unfreeze itself. This can, however, take quite a lot of time. During this time, the ice on the evaporator coils is slowly being turned into water.

How Long Does It Take To Thaw A Frozen Air Conditioner
Ice on the evaporator coils looks brownish color due to inclusion of dirt, dust, and so on. It can take quite a long time to melt without some help.

Ice has a very high latent energy; 336 kJ per kg, to be precise. When you leave an AC, the speed of thawing a frozen air conditioner depends on:

  • Indoor temperature. Higher temperatures will unfreeze the air conditioner faster. Usually are dealing with room temperature (77°F).
  • Amount of accumulated ice. If the ice on the AC coils has been accumulating for some time, it will take longer for all the ice to be melted.

As a general consensus, it can take about 1 day to thaw a frozen air conditioner naturally. It is, however, very hard to determine exactly the time it takes for the AC to thaw completely in this way. We usually say that every air conditioner can be unfrozen in 2 days maximum.

In any case, you should not turn on the ‘Cooling’ setting if you are not sure that all the ice on the indoor AC coils has been turned into water and drained adequately. That’s why it is always best to check the coils themselves – remove the cover and the access panel – to make sure all the ice is gone and wait for about 30 minutes for all the water to be drained.

after how much time to check if air conditioner is unfrozen

Now, you can speed up the unfreezing process by either increasing the airflow over the coils, the temperature of that airflow, or both:

How To Minimize The Time It Takes To Thaw A Frozen Air Conditioner?

As we explain in the article about unfreezing methods cited above, you can fasten up the unfreezing process by:

  • Running AC fan only. You should turn off the ‘Cooling’ mode. You can switch the AC fan mode from ‘Auto’ to ‘On’. This will increase the airflow over the frozen evaporator coils and thaw them quicker (in under 1 hour).
  • Using a hair dryer to thaw the frozen air conditioner faster. A hair dryer provides both an increase in airflow and in airflow temperature; it can thaw all the ice of the evaporator coils in less than 30 minutes.
  • Optional: Turning on ‘Heat’ mode, if you have a heat pump. Heat mode will switch the flow of refrigerant and warm the frozen evaporator coils very quickly. It can take less than 10 minutes to thaw a frozen air conditioner with the heating mode.

In any case, after all the ice is gone, you should always wait for about 30 minutes in order to be sure that all the water was adequately drained.

All in all, we have seen that how long does it take to thaw an air conditioner depends on if we just leave it to unfreeze naturally, and if we provide airflow (with fan only setting), use a hair dryer or even ‘Heat’ mode to unfreeze the AC unit. It should take a maximum of 2 days for the air conditioner to thaw completely. We can also speed up the unfreezing process to less than 1 hour or even less than 10 minutes.

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