Quick and Effective Tips to Unfreeze Your Air Conditioner for Optimal Cooling

Unfreezing an air conditioner is important because a frozen air conditioner can damage your compressor. Having a frozen air conditioner during the scorching summer months can be miserable and an inconvenience. If you’re running your air conditioner frozen and your compressor becomes damaged, this can not only be expensive, but a pain to repair.

If you need to unfreeze your AC unit fast, you should turn off your unit, switch your thermostat fan on, locate the source of the problem, and monitor the thawing over a few days. These are important steps to ensure that your AC unit is completely thawed and dried out.

When dealing with a frozen AC unit, you’ll probably start running into signs of a problem before you even notice it is frozen. While going through this process, you may run into low refrigerant levels, dirty filters, faulty blow motor fans, and more. Taking these proper steps below will not only help you defrost your unit, but could also save you money down the road.

Signs That Your Air Conditioner is Frozen

Three signs that your air conditioner is frozen are that it blows out warm or hot air, has visible ice on the air conditioning unit, or there is water leaking from your unit. When your air conditioner becomes frozen, the majority of the time it is due to a frozen coil. This can happen with air conditioners for windows or even portable units.

When your air conditioner is frozen, you can spot these problems on your own, as well as fix them. In some cases, your refrigerant line may be frozen if it’s not the coil. This would be an extreme circumstance and is hard to tell since they are well hidden.

1. AC is Blowing Warm or Hot Air

If your air conditioning unit is blowing warm or hot air, this could be due to a frozen coil. If your coil is not absorbing heat for a certain amount of time, this will cause your coil to become frozen. Certain things could prevent hot air from being around your coil.

If your coil is frozen, this means your airflow is being obstructed somehow. A reason for this can be due to a dirty air filter. Any dirt that gets into your unit could block air from entering the return vent, thus creating your coil to freeze. 

2. Visible Ice on the AC Unit

If you have visible ice on your AC unit, you may have ice on the inside too. Checking for ice on the inside of the unit can be difficult, but if not dealt with can cause more damage. If you live in a humid part of the country, it’s very common that you’ll see your AC unit dripping water.

Not only can water drip on the outside when this occurs, but it could also build up on the inside. One way to check if your unit has ice on the inside is if your drip pan is full of water. A full drip pan will show you that you had ice built up somewhere in the unit.

3. Water is Leaking From the AC Unit

If your AC is frozen and leaks water from the bottom, this could be due to a dirty air filter, low refrigerant level, a crack in your drain pipe, or your evaporator coil is frozen. When you begin to notice water leaking from the bottom, you’ll need to investigate further to find the root cause. In some circumstances, you may need to call a technician to fix it.

If you have a dirty air filter, it’s good to change them every 60 to 90 days. Replacing your air filter may help with the leaking. If you have a low refrigerant level you’ll want to call your local HVAC technician to restore your levels.

What Could Cause An Air Conditioner To Freeze Up?

If you have an AC unit, there are several reasons why it may freeze up. Some of these reasons may be a low refrigerant level, lack of airflow, mechanical problems, clogged condensation lines, a power issue, or dirty coils. AC units freeze up a lot, so many of these issues commonly occur.

If you suspect your AC is malfunctioning, your entire AC unit will become disrupted. A malfunctioning AC unit will cause your evaporator coil to tell the refrigerant to over-cool, which would cause freezing. By understanding these common reasons for your AC unit freezing, you can get ahead of the problem and try to prevent freezing and any further damage. 

A Low Level of Refrigerant

To check how much refrigerant is left in your AC unit, you’ll need a thermometer and a refrigerant slider. The first thing you’ll want to do is check what type of refrigerant your AC unit uses. Second, you’ll want to check the pressure by checking the gauge.

Third, you’ll want to find out what the temperature is of condensation and evaporation. Fourth, you’ll want to use your thermometer to measure the temperature on your installation. Lastly, you’ll want to calculate your superheating and subcooling.

Once you have determined that you have a low level of refrigerant, you should contact your HVAC technician to refill your refrigerant. This process can’t become expensive so you must have this completed by a technician.

Lack of Airflow

A dirty filter can cause a lack of airflow in your AC unit, causing it to freeze. This occurs when cold air is trapped inside your unit and will cause ice to form on your coils. Before your AC unit begins to freeze, you may be able to notice some red flags that point to a freeze beginning.

To replace the filter in your AC unit, you’ll first want to turn your unit off to prevent any dirt or debris from blowing around. Once you have turned off your unit, you’ll want to open up the vent and remove the dirty filter. When replacing your filter, you’ll want to ensure that your airflow arrows are pointing toward your HVAC unit.

Mechanical Problems 

Your AC unit may also freeze up due to a broken blower fan. Your air conditioning unit has a blower fan that operates by using a motor. The blower fan will pull warm air from inside your home and push out cooler air from the unit.

If you have a broken blower fan or motor, your air conditioner won’t have enough airflow, which would then cause ice to form. If you don’t have enough air moving throughout your AC unit, the evaporator coil will collect condensation and freeze. If you do have a broken motor, you will notice very little or zero air moving through your vents or a slow fan speed.

Clogged Condensate Lines

If your AC unit has frozen, this could be caused by clogged condensate lines, which could lead to larger problems down the road. When you have a clogged condensate line, this will cause your unit to hold more water than it’s supposed to. Once your AC unit has dipped below freezing level, the water that is held inside the unit will make your evaporator coils freeze.

Another problem you may run into if your AC unit is collecting too much water from a clogged condensate line is that you’ll notice water collecting at the bottom of the pan. Having a clogged condensate line will cause your pan to overflow, which would then create damage inside your home.

A Power Issue 

Another reason your AC unit may freeze up is due to a power outage. During the summer and the scorching hot months, often you may run into a severe thunderstorm that could take out your power. During severe thunderstorms, lightning will sometimes cause your power to go out and trip your breaker.

Even other reasons not due to storms may cause a power outage and your breaker to trip. When your circuit-breaker trips, this will cause your AC to shut off, but could also cause it to freeze unexpectedly. The power will affect the blow motor, which would then cause your evaporator coil to freeze.

Dirty Coils

Dirty coils are one of the most common reasons for your AC unit freezing. When your coil is frozen, ice will block the air from flowing in your system. A tiny bit of  ice can eventually turn into blocks of ice if you have a dirty coil.

Dirty coils can cause your AC unit to freeze because the dirt prevents the coils from absorbing water. If your AC unit is frozen and is older than a decade, it’s worth just replacing the entire unit. Coil replacements are more than just replacing a regular part.

If you suspect that you need a coil replacement, you should contact an HVAC technician that will help you with replacing your entire unit. New evaporator coils would help your AC unit run again, but it will cost you more money down the road. 

How to Unfreeze an Air Conditioner Unit Fast

If you need to unfreeze your air conditioner unit fast, there are certain steps you’ll want to take before beginning the process. First, you’ll want to turn off your AC unit to prevent any further damage from occurring. Second, you’ll want to switch your thermostat fan on to continue to unfreeze your unit and begin the drying-out process.

Third, you’ll want to determine what is causing your unit to freeze, such as a dirty filter, faulty blow fan motor, or low refrigerant levels. Lastly, you’ll want to closely monitor your AC unit to make sure there aren’t any additional damages and that your unit has completely thawed and dried out. 

Step 1: Turn Off Your AC Unit

To turn off your AC unit, you’ll need to do more than just simply turn it off from your thermostat. Even if you have a change in temperature one night, this could cause your AC unit to briefly turn back on. If your AC unit briefly turns on, outside weather may get into the inside of your AC unit and cause damage.

To prevent your AC unit from turning back on, you’ll need to shut your unit off completely. To turn your AC unit off completely, you’ll want to locate your breaker switch that’s on the outside. Find the breaker switch under a flip-up area located near the condenser unit and turn the switch to the off button.

Step 2: Switch Your Thermostat Fan To ON

When you need to unfreeze your AC unit fast, turning on your thermostat fan can help speed up the process. Once you have melted all of the ice in your AC unit, you’ll want to turn the thermostat fan on the “fan only” mode. When the thermostat is on the “fan only” mode, this will continue to unfreeze your AC unit and will dry out your system.

Any ice that is left over will melt and this will dry the inside of your AC unit. If you still have moisture on the inside of your unit and you turn the unit on too early, this could cause your AC unit to refreeze.

Step 3: Locate The Source Of The Problem

There are a few common reasons why your AC unit is freezing up. Some of these reasons are that a dirty filter is causing a blockage, you have low refrigerant levels, or you have a faulty blow fan motor. If you have a dirty filter, this will create very little airflow and will cause your AC unit to freeze.

If you have low refrigerant levels, this is a big problem for AC units and one of the main reasons why they freeze. If your levels are low, this will cause an expansion which will decrease the temperature and cause your unit to freeze. Lastly, a faulty blow fan motor could cause an AC unit to freeze if you don’t have enough air blowing throughout your system.

Step 4: Closely Monitor Your Air Conditioner

Once you have completely thawed your AC unit, you should closely inspect it to make sure it is free of ice and completely dry. Before you turn your AC unit back on, you’ll want to make sure this step is completely done. You’ll want to closely monitor your air conditioner for at least a few days.

During the summertime, you’ll want to keep your AC unit working in tip-top shape, especially on really hot days. Having routine maintenance and your unit inspected will help you spot and address problems early on to prevent your AC unit from freezing and thawing. 

How Long Does It Take An AC Unit To Defrost?

To defrost your AC unit, this may take you anywhere from 2 to 24 hours to thaw out completely. The length of time it takes to defrost generally depends on the size of your AC unit. Other factors that determine the time is the temperature outside and how much ice has built up on your unit.

If you have a larger AC unit and the temperatures are cooler outside, your unit may take longer to defrost. If you have a smaller AC unit, this may take you anywhere between 2 to 8 hours to completely defrost. If the temperature is hotter outside, this will also help speed up the thawing process.

What Should I Watch For While It is Defrosting

While your AC unit is defrosting, you should watch out for your drain pan and the condensate drain line. Your drain pan is designed to catch any water that runs out of your AC unit, so naturally, when defrosting you’ll want to keep an eye on this particular spot. Not watching out for the drain pan can cause it to overflow and damage your home.

You’ll also want to watch out for your condensate drain line. If you have a clogged condensate drain line, this will not only cause your unit to freeze but may also cause unwanted bacterial growth.

1. The Drain Pan

With every AC unit, there is a drain pan that is designed to catch any condensation that happens to drip from your unit. If you have a frozen coil or low refrigerant levels, this may cause your drain pan to become filled with water. If you see that your drain pan is filled with water, the first thing you should do is check your coils.

When you need to remove the water from your drain pan, you’ll want to use a shop vacuum, and then get rid of the water. In addition, you’ll also want to make sure you remove any dirt that has built up around or inside the drain to make sure your water can drain properly. 

2. The Condensate Drain Line

If your AC unit is frozen, you should also keep an eye out for your condensate drain line. If you have a clogged condensate drain line, this will keep water inside of your unit which will cause your unit to freeze. If there is moisture inside of your condensate drain line, this can also cause a freeze and your AC unit will turn off.

To make sure your drain line isn’t clogged, you should do a proper check once a month. If your condensate drain line is clogged, this will also cause your drain pan to overflow with water, which may cause bacteria. In case your drain line becomes clogged, you can pour bleach down the opening of the line. 

Can I Pour Hot Water On My Frozen Air Conditioner?

Yes, you can pour hot water on your frozen air conditioner to unfreeze it. Even though there are other routes to take to start the thawing-out process, pouring hot water on your AC unit will help unfreeze the coils. If you choose to pour hot water on your unit, there are some things you should keep in mind.

If the temperature drops after you have poured hot water on your unit, this may cause your unit to refreeze. If you’ve poured hot water on your AC unit and it still hasn’t solved the problem, you should contact your local HVAC technician.


If you need to defrost your AC unit, you should check for low refrigerant levels, dirty coils, a faulty blow fan motor, or a clogged condensate drain line. In addition, you should also make sure you don’t have any furniture blocking air vents in your home that would obstruct airflow.

Leave a Comment