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Can You Recharge A Window Air Conditioner? | An Easy Guide

Window air conditioners will need to be recharged as they age and leak. However, the process must be performed by a professional HVAC technician, as handling the refrigerant requires special equipment and certification. Plus, refrigerants are flammable and toxic if not handled with care.

Can You Recharge A Window Air Conditioner

Window air conditioners are the most popular heating, ventilation, and air conditioning (HVAC) systems for individual rooms and small spaces.

Window air conditioner units work by drawing in warm air, passing it over evaporator coils that contain a refrigerant, and then expelling the cool air back into the room. However, over time, the refrigerant in a window air conditioner unit can get too low for the AC to run effectively. 

That said, you might be wondering if you can recharge a window air conditioner yourself to restore its cooling power and perhaps save a few bucks. While refrigerant recharge is possible, it is not a do-it-yourself task. Hence, I always recommend hiring a professional HVAC technician to recharge window AC units.

That said, regular maintenance is important for window units to enjoy optimal cooling performance. So, make sure you clean or replace any dirty air filter, clean the condenser coils, and inspect the unit for any signs of damage. 

To get started, here are some signs that your window AC requires a refrigerant recharge… 

Signs That A Window Air Conditioner Needs To Be Recharged

Signs That A Window Air Conditioner Needs To Be Recharged

1. Reduced Cooling Capacity

As your window air conditioner ages, it will start to be less effective in lowering the temperature of the room. To check the cooling capacity of the window AC, place your hand in front of the unit and feel the amount of cold air blowing. If you feel low air pressure or warm air, it’s high time you get the refrigerant recharged. 

2. Your Electric Bill Is Higher Than The Usual

Another sign could be a high electricity bill, which can be due to leaking refrigerant. As it leaks, it will consume more power and cost more money to run it. If your electric bill is unusually high, it may be an indication that you need to recharge your refrigerant. When that happens, check for any leaks and fix them immediately.   

3. Ice Buildup On Evaporator Coil

A build-up of ice on the refrigerant line or evaporator coils can be another sign that you need to recharge your window air conditioner. Such a build-up of ice indicates that the refrigerant in your window AC units is leaking and freezing outside the refrigerant line or evaporator coil. When that happens, you will have to fix the leak and recharge the refrigerant of your window AC unit.

4. A Bubbling And Hissing Sound From The Refrigerant Line

Lastly, place your ear in front of the AC and check if there is a bubbling or hissing sound coming from the refrigerant. If you hear any bubbling and hissing sound, it indicates a leak. As such, you must fix the leak and recharge the window AC unit immediately.

All of these signs listed above can happen one at a time or even together at once. So, carefully observe them and recharge your window air conditioner even if you notice only one of the signs.     

How To Recharge A Window Air Conditioner

Once you observe signs that your window AC unit may need to be recharged, you should know how to do that. If you are unsure of it, follow these easy steps on how to recharge a window air conditioner:

Step 1 - Turn Off The Unit

To prevent any unwanted accidents, turn off the unit and unplug AC power plugs and sockets.

Step 2 - Locate The Refrigerant Lines And Service Valves

Once you have removed the air conditioner from its place, dismantle the window AC unit using a screwdriver and locate the service valve. You will also find the refrigerant lines behind the unit, near the condenser coils.

Step 3 - Check For Leaks

After you locate the service valve, check for any leaks. Some easy ways to check for leaks; 

  • Apply some soap over the refrigerant and start the unit; if you see any bubbles forming, it means there is a leak. 
  • Use a leak detector, as it will give a visual or audio signal in case of a refrigerant leak. 
  • Fill some fluorescent dye in the unit, turn it on, and then use an ultraviolet lamp or leak detection flashlight.
  • Nitrogen can also be used, but it will require the help of an expert as all the valves need to be closed off. 

Step 4 - Attach The Refrigerant Hose To The Service Valve 

Using the manual guide, locate the compressor. After finding it, attach the service valve to your kit. Also, attach the tap (valve) to the other free line.

Step 5 - Check The Pressure Gauge

Next, use a two-pressure valve gauge to check the pressure of the refrigerant. Check the window air conditioner unit's manual for the correct pressure gauge. Set the pressure according to the manual guide instruction. If you need help with how to do it, you can call a professional to check the pressure gauge, as it can get complicated. 

Step 6 - Add Refrigerant 

Now that you have checked the pressure gauge, you can add the refrigerant. You can do this by turning on the window AC unit and keeping it at the maximum setting. Connect the tap and service valve of the air conditioner to the freon tank, slowly add the refrigerant and recharge it.  

Step 7 - Monitor The Pressure Gauge 

Check the window AC unit's user manual for the required amount of refrigerant and monitor the pressure gauge accordingly. Once the gauge indicates reaching the required amount, decrease the unit power. Any extra refrigerant beyond what is required is a waste of resources. 

Step 8 - Disconnect The Refrigerant Hose And Close The Service Valve

Plug out the air conditioner and disconnect the refrigerant hose by removing the tap and service valves connected to the freon tank. By doing this, you close the tap and service valves, and stop the flow of extra refrigerant into the air conditioning unit. Anything beyond the instructed level is a waste of refrigerant and money.   

Step 9 - Turn On The Unit And Check For Leaks

You can turn on the unit again and check for leaks. If there are no leaks, your window AC will start cooling the room properly. However, if there is a leak, it will still cause a problem, indicating that the fix was improperly done and ineffective. As such, it will be best to hire experts, as the problem may be beyond your expertise. 

When To Call A Professional

Knowing when to call a professional is important so that you do not damage the device even more with a DIY project. So, it is in situations like those listed below that you should get immediate professional help.  

1. When There Is A Refrigerant Leak  

It may be time to call a professional if your window AC unit is still not cooling after you have recharged it because of leaks in the unit. Fixing a leak can get complicated if you do not have the right tools and skills. Therefore, instead of troubling yourself with the work, hire a professional expert on window AC units.

2. When The Unit Is Still Not Cooling After Recharging. 

You may have tried to recharge the refrigerant yourself; however, the cooling system may not work despite doing that. This could be due to several reasons. For example, it could be the depletion of Freon that needs replacing. If that happens, you should call a professional to diagnose it, as the problem could be due to other issues. 

3. When The Unit Is Making Strange Noises

If you hear a strange noise coming from the Window AC unit, the problem might not just be about leaks and leaking refrigerant. For instance, it could be the case that there is a broken part inside the window air conditioner, and it will have to be replaced. In such a case, it will be more beneficial to call and get professional help, as diagnosing an air conditioner requires expertise. 

Tips For Maintaining Your Window Air Conditioner

Once you recharge your window AC unit, maintaining it from time to time will be crucial so that it does not break again. Here are some simple tips on how to maintain your window air conditioner. 

1. Regularly Clean Or Replace the Air Filter

Keeping a timely schedule for cleaning the air conditioner is important. To clean the unit, fill a spray bottle with water and add some hydrogen peroxide. After that, spray the mixture in front and at the back of the unit. The hydrogen peroxide mixture works as a cleaning agent for the unit. You must turn the unit off before you do that. 

A window AC has a removable air filter that collects dust and other particles. You can remove the air filter inside the unit and clean it with water. Once it's dry, place it back and turn on the window AC. 


If the air filter is too dirty and cannot be cleaned, replace the air filter with a new filter.

2. Keep The Unit Away From Direct Sunlight

Another way to maintain your window air conditioner is to keep the unit away from direct sunlight. As direct sunlight will heat the unit both outside and inside, the cooling will be less effective. Therefore, see if you can place your window AC in a place where it would not be exposed to too much sunlight and heat. 

3. Clean The Coils and Fins

It would be best to clean the coils and fins regularly, as they can become less effective with the accumulation of dirt. As the coils and fins in the unit can get bent, you will have to straighten them if that happens, as it can lead to premature breaking. Take a knife or fin comb and wear proper gloves to comb through the bent areas. Slowly and carefully straighten all the bent areas as best as you can.   

4. Keep The Room Well-Ventilated

Lastly, you have to keep the room well-ventilated when you use a window air conditioner so that the cooling effect can be optimized with a better flow of air in the room.  

In order to ventilate the room, keep the windows open and close the doors that lead into other rooms. This will result in more effective cooling as there will be better airflow around the room. 

FAQs About Your Window AC Unit

  • What is Chlorodifluoromethane?

    Chlorodifluoromethane (CFC-22 or R-22) is a colorless, odorless gas belonging to the family of chlorofluorocarbons (CFCs). It was used as a refrigerant in air conditioning and refrigeration systems due to its ability to absorb and release heat efficiently.

    However, it was later discovered that CFCs were harmful to the environment. For instance, releasing this gas into the air can deplete the ozone layer, thereby exposing the environment to UV radiation. 

    Hence, nowadays, alternative refrigerants like hydrofluorocarbons (HFCs like 1,1,1,2-Tetrafluoroethane) and hydrochlorofluorocarbons (HCFCs) are used in newer window AC units. These refrigerants are not fluorophores, but they do contain fluorine atoms, which give them their unique properties.

  • What does the United States Environmental Protection Agency state about Window Air Conditioners?

    The United States Environmental Protection Agency (EPA) regulates the use of AC units to reduce the environmental impact caused by their functioning. One of the key regulations is the Energy Star program, stating that an Energy Star-certified window AC consumes about 9% less energy than standard models.

    One of its guidelines also mentions the safe disposal of HVAC equipment, as they contain refrigerants and other chemicals that can harm the environment. As such, EPA recommends proper recycling and disposal at designated facilities instead of dumping your old ACs in landfills. 

  • How does refrigerant work?

    Refrigerants work by changing phases from a liquid to a gas and back to liquid again in a continuous cycle, absorbing and releasing heat in the process. 

  • Can You Recharge A Window Air Conditioner

    Final Words

    That said, I tried my best to show an easy way to recharge your window air conditioner. You can follow these easy steps mentioned above for a step-by-step guide on how to recharge your window AC unit. 

    Along with that, you must regularly maintain your window unit in order to avoid the need to recharge. Without a proper schedule for maintenance, your window air conditioner unit will break sooner than you expect and cause problems. So, clean and follow a maintenance routine as regularly as possible. 

    Lastly, some of the problems with your window AC unit will require professional help as it will require special tools and expertise. Based on the severity of the problem, you should hire an expert on window AC so that they can fix the problem. 

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