Updated at: 12-08-2022 - By: Sienna Lewis

When you turn on your window AC, does it blow out lukewarm air? You don’t think the air is as crisp as it used to be, do you? Then you need to roll up your sleeves and educate yourself on how to recharge a window air conditioner. The following explains why we have reached this conclusion.

There is a leak in the closed-loop mechanism of the air conditioner if it suddenly stops blowing cool air. Due to the leak, the refrigerant has been lost. This is the only material capable of reducing the temperature of warm air. If you don’t refill it, your air conditioner won’t work as efficiently as it did before.

The modern window air conditioner is a device that is installed in the window casing to cool the air. Typically, they are put to service during the warmer months and then either shut down or dismantled during the colder months. However, they will eventually run out of juice and need to be recharged, just like any other electronic item. It is not unusual to need to recharge a window air conditioner.

When a window air conditioner has a leak in its closed-loop system, it won’t provide cool air. Your air conditioner’s performance will suffer because of this leak if the refrigerant is not replenished. Let’s dive deeper into whether it’s time to recharge your window air conditioner, what factors into that decision, and how to do it yourself.

How To Recharge A Window Air Conditioner

Make sure it is legal in your area to work on air conditioners before we go into the basics of how to recharge a window unit. Almost all of them don’t.

Because of this, we advise that you consult your local statutes in order to draft a regulation that will allow you to attempt such a project. You shouldn’t fill up your AC unless you’ve verified that doing so won’t put you in violation of any regulations.

How To Recharge a Window Air Conditioner Unit – HVAC How To

1. Get The Necessary Supplies

Refilling a window air conditioner requires the following supplies:

  • Gloves
  • Safe vision aids
  • Screwdriver
  • Detector of Leaks
  • Refrigerant
  • a Freon kit

2. Unplug The Unit

In order to turn off a window air conditioner, all you have to do is remove the plug from the power outlet it is connected to, as opposed to the much more involved process of turning off a central air conditioner. In order to disassemble and inspect their inner workings, all that is required is to remove the plug.

3. Wear Personal Protective Equipment

Before continuing, double-check that you are using protective eyewear and gloves. Freon, the refrigerant you’ll be adding, is a potent carcinogen. And if it comes into contact with unprotected skin, it can induce frostbite. Please, then, take all the safety measures you can.

4. Open The Window AC Unit

Most ancient window air conditioners’ inner workings are exposed by simply sliding the front ends out of the way. Some, especially newer models, require the use of a screwdriver for disassembly. Examining the owner’s manual is the best way to learn how to operate your device properly.

5. Check For Leaks

Here are a few ways to look for water leaks:

  • To use soap, combine equal parts liquid detergent and water. Apply it to the valves, hoses, pipes, and other moving parts involved in the transfer of the refrigerant, and then power up the system. Observing the occurrence of bubbles can help locate a leak.
  • Turn on the leak detector and protect the outdoor part of it from drafts by covering it up. Run the leak detector’s probe near the outside condenser unit while it’s on. Depending on the type of leak detector, an audible or visual signal (or both) will be produced if a leak is present.
  • Nitrogen: This technique should be carried out by professionals only. It requires closing any valves that connect to upstream or downstream apparatuses, pressurizing the unit with nitrogen, monitoring its pressure at the start and then measuring the pressure after a few minutes. Pressure loss indicative of a leak is discernible.
  • This procedure, which employs fluorescent dye, is straightforward enough for amateurs to carry out. All that needs to be done is to inject a tiny amount of fluorescent dye into the system and turn it on. The dye follows the refrigerant around and collects at all potential leak points. A leak detection flashlight or UV lamp can be used to locate the source of a leak (it will be glowing).

9 Easy Steps to Recharge a Window Air Conditioner

6. Fix The Leak

A slow leak in your unit means that you can get away with not fixing it and instead just “boosting” the system to make up for the lost refrigerant. However, if the leak is rapid, the region through which the refrigerant is escaping may need to be soldered back together.

7. Connect The Valves To The Compressor

You should consult the user handbook to identify the location of the compressor and the two lines leading away from it. After that, connect the service valve in your toolkit to the compressor’s line. At the very least, one line should be unattached to the compressor. Fasten it to the tap’s shutoff valve. Your Freon kit will feature both of these necessary valves.

8. Connect The Valves To The Freon Kit

Almost all Freon kits include a graphic that shows how to attach the two valves (service and tap) to the Freon container. The diagram will help you place the Freon tank or other refrigerant container between the two valves.

Final Step: Recharge Your Window Air Conditioner

Check for leaks and make sure all connections are tight. Then, activate the air conditioner in the window and set the power to maximum. The Freon tank is now connected to the air conditioner via the service and tap valves, and the refrigerant will begin to flow in the other direction.

To find out how much Freon your system needs, see the manual. When the Freon tank’s indicator reads full, turn off the machine immediately. In order to start your air conditioner, you must first disconnect it from the wall, then turn off the service and tap valves.

Things To Know About Recharging A Window AC Unit

If you want to get the most out of your recharge process, you should know these two things before you get started:

In a closed-loop system, refrigerant (also known as Freon) will only run out if there is a leak. If your system is low on freon, you likely have a leak that needs to be fixed before you can recharge it. Recharging it could extend its useful life by several years if the leak is minor.

Use The Same Refrigerant is very important. Older AC units were using R-22 refrigerant. The AC units that were built since 2000 were using R-410A refrigerant, which is the most popular type till today. The newer units contain R-32 refrigerants. Check on the label on your window air conditioner to see what type of refrigerant does your unit use.

I Can’t DIY This: Who Do I Call?

Refrigerant consistency is crucial, so make sure you always use the same kind. R-22 was the original refrigerant used in air conditioners. R-410A refrigerant is still the most widely used variety, and it was used in all air conditioners manufactured after the year 2000. Refrigerants of R-32 type are used in the newest models. Your window air conditioner should have a label indicating the type of refrigerant it uses.

The Environmental Protection Agency (EPA) stipulates that anyone you employ to re-gas your window air conditioner must be licensed in HVAC. Simply utilize our site to find licensed HVAC specialists in your area. In addition, if you need assistance recharging your air conditioner, you may easily identify qualified service providers in your area. Just consult Google for assistance.

We’ve written a comprehensive piece explaining the inner workings of a Smart HVAC system for anyone interested in reading it.


1. Can You Put Freon In A Window Air Conditioner?

A port for adding Freon is typically not pre-installed in window air conditioners. It takes about 1-2 pounds of refrigerant to properly charge a single air conditioner.

2. How Much Does It Cost To Recharge A Window Air Conditioner?

Having a professional recharge a window AC can cost anything from $100 to $150. In contrast, do-it-yourself kits for replacing refrigerant may be purchased for $20 to $30, however it’s recommended that a pro do the job.

3. Can I Recharge My Window Air Conditioner Unit Myself?

Due to potential dangers to one’s health and the environment, the EPA advises against DIY Freon AC recharge and replacement. In order to replace the Freon in your air conditioner, you must hire an EPA-certified service expert.

4. How Do You Check Freon In Window Air Conditioner?

To determine whether or not the Freon level in your window air conditioner is enough, you should feel the air coming out of the vents. Keep a thermometer adjacent to the unit at all times to see if the air is actually getting cooler than it should be. You should record the temperature a few minutes later.

5. How Long Does Freon Last In A Window Air Conditioner?

The compressor and refrigerant of a window air conditioner usually last between 12 and 15 years. Of course, how often you run your air conditioner and how well it is maintained also play a role.

How To Recharge a Window Air Conditioner Unit – HVAC How To


Finally, it is important to note that in most parts of the country, it is against the law for anybody who is not a professional HVAC technician to recharge their window air conditioner. However, even if you are within your rights to lawfully power up your unit, you should still seek the advice of an expert if you run into any problems.

On the other hand, it is just as important to only refill the system with the amount of refrigerant that is actually depleted. The Environmental Protection Agency (EPA) cautions that while undercharged systems have higher operating costs and are less efficient, overcharged systems have a larger chance for leakage.