Can You Recharge a Window Air Conditioner? (How To Guide)

When you hear someone saying they want to recharge their window AC, they mean adding more coolant to it and maintaining the system’s refrigerant pressure.

Many people who wish to do the job themselves would ask, “can you recharge a window AC on your own?”

Yes, you can take the DIY route and recharge a window AC. However, if you need to add Freon to your climate control system, you’ll likely need the services of a cooling technician.

Convention dictates that you should have a yearly checkup for your AC, where the technicians check your coolant levels and see if its weight and pressure are maintained.

Meanwhile, some window air conditioners are more energy-efficient than others and require fewer maintenance checks.

Window AC Parts Diagram

What Is An Air Conditioner Refrigerant

A refrigerant is a fluid inside air conditioners that removes heat from the room and throws it into the atmosphere.

How does it work? To do this, it goes through phase changes, transitioning from liquid to gas when absorbing heat and back to the fluid when compressed.

Several refrigerants are available to use. What differentiates them is their thermodynamic properties, toxicity, non-corrosive nature, and flammability. The most common option is CFCs.

Freon was the name of a refrigerant ‘R-12’ developed by Dupont, and it was the most common CFC used as an air conditioner refrigerant. However, CFCs were found to deplete the ozone layer and were aptly phased out.

In the last two decades, CFCs were replaced with HCFCs, the most common one being ‘R-22’. But these refrigerants still contain chlorine which is not ecologically friendly.

Therefore, manufactures came up with HFCs to remove chlorine from refrigerants. This variant poses no significant ecological risk.

Keep in mind that the most common HFC in use is R-410A, also called Puron, and has high energy efficiency.

Window AC Refrigerant

Signs That Your Air Conditioner Needs Recharging

Without sufficient refrigerant, your AC won’t be able to cool any space properly. But before you go about calling for a technician, there are a few ways to tell if your AC needs recharging:

Increased Energy Bills

If you notice a sudden spike in your energy bill and you haven’t been using your air conditioner more than usual, it could be a sign that you have a refrigerant leak.

Without sufficient refrigerant, your AC cannot get rid of enough heat per cooling cycle, making your system work harder than average to provide cooling at the same rate. The longer the run time of the air conditioner, the higher your energy bill

Warm Air Blowing From Supply Vents

Since refrigerants absorb heat from your home and transfer it outside, low refrigerant levels mean that heat transfer is insufficient. Therefore, your AC won’t absorb enough heat, and you might notice warm air coming through your supply vents.

Ice Or Frost On Your AC

If you notice ice or frost on your air conditioner, it could be a sign of low refrigerant levels. With deficient refrigerant levels, the temperature of the refrigerant can drop below the designed temperature, causing ice to build on the evaporator coil or the refrigerant lines.

Related Article Why is the AC Freezing Up?

Hissing Or Bubbling Noise

If you notice any hissing or bubbling noise emanating from your outdoor AC unit, it could be the sound of refrigerant escaping from a leak. A hissing sound signifies the refrigerant is leaking in gas form, while a bubbling indicates a liquid leak.

How To Remove Freon From A Window AC Unit

You can only remove Freon from an air conditioner by using a machine known as a reclaimer. This machine is specially designed to capture Freon, filter out any impurities from it, and store it for later use.

According to the EPA, only Section 608 certified professionals can handle Freon removal from air conditioners and refrigerators.

It addresses the handling and recycling of refrigerants and seeks to reduce refrigerant emissions into the atmosphere. This rule applies even if you’re adding Freon to window AC units.

You must first remove Freon for your AC unit to be liable for disposal. Then, you should call your municipality waste disposal department and seek the disposal guidelines for Freon in your local area.

Please take note of all the instructions and make sure to follow them closely!

How To Recharge A Window AC

Recharging the refrigerant in a window AC is not something that most people do and hence are not familiar with the process. But is there a way to recharge a window air conditioner on your own?

Yes, you can go the DIY route and recharge a window AC unit by yourself, provided you have the right tools and follow the prescribed instructions.

Homeowners can employ two methods of recharging their window air conditioners; the technology-enhanced method or the DIY low-cost method.

The latter is the more-used method by most homeowners. However, we would strongly side against this as there can be some security drawbacks.

Before attempting to recharge the refrigerant in your window air conditioner, you will need these parts:

  • Bullet Valve
  • Refrigerant
  • Recharge Hose

You can find these parts in most window air conditioner recharge kits at Walmart or other home maintenance stores like Home Depot or IKEA.

Windows AC Parts Diagram in 3D

Low-Cost Method To Recharge A Window AC
  • Join the Bullet valve into the low-pressure line
  • Join the refrigerant can’s flow into the recharge hose
  • Join the recharge hose with the Bullet valve

A bullet valve is a simple tool that allows you to add a recharging port into your air conditioning unit. Window ACs lack service ports, so a bullet valve will enable you to connect to the line quickly.

Furthermore, the type of refrigerant your air conditioner uses will usually be mentioned on the appliance.

Older units use R22 which is out of service nowadays, with newer units using R-410A. Whenever you are recharging an AC, make sure not to mix two refrigerants!

Additionally, each air conditioning unit will require a particular pressure to be able to cool effectively.

With low refrigerant, the pressure in the unit will also be low, rendering it unable to cool. An overfilled AC unit will also deem the pressure too high, providing inefficient functionality.

Recommended Method To Recharge A Window AC

The first step you need to follow is to check for any leaks. If there is only a tiny slow leak, you can get by with a slight boost of refrigerant every year or so. However, a fast leak will need to be repaired quickly before you refill any refrigerant.

You can detect leaks through visual inspection or more detailed techniques like filling the system with nitrogen and using soap to look for bubbles from the source of the leak.

You can also buy leak detectors at home improvement stores. Keep in mind that most leaks occur near joints, where they require soldering.

Meanwhile, window air conditioners do not have service ports where you can hook your gauges, so you can either solder a port or use a piercing valve kit. A piercing valve is the most popular technique to install a Schrader Valve on an air conditioner.

After you have repaired any leaks and installed a service port, it is time to add the refrigerant. We already mentioned how to put Freon in window ACs, but most units use R-410A today so make sure to read your device’s label.

Also, remember that you will need an HVAC gauge and the required refrigerant for your appliance.

Hook your gauges to the service interface and the refrigerant tank, and make sure to watch the pressure on the gauges.

People Also Ask (FAQ)

How much does it cost to recharge a window air conditioner?

A professional window air conditioner recharge can cost you anywhere from $100-$150, depending on your unit’s model. Some units require more work, thus cost more to recharge,

How long does Freon on a window air conditioner last?

Freon refrigerant is typically supposed to last for a lifetime, but you should expect it to last at least 10-15 years if there is no leakage.

Is it bad to run an AC with low freon?

Running your air conditioner on low freon can be pretty taxing for your compressor and can cause severe damage to your unit. Therefore, you should refrain from doing so and check your Freon levels often.

Is it okay to spray water on your air conditioner?

Yes, it is okay to spray water on your air conditioner but not on all parts. Some electrical components are exposed, and you should try to keep all liquids away from those regions.


These are some of the ways you can attempt a window air conditioner Freon refill by yourself. Remember to follow the instructions, use the correct refrigerant, and contact a technician if you encounter any significant issues with your unit.

Related Article How Does a Window AC Work?

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.