How to put Freon in AC unit? [11-Step Guide to add refrigerant]

If you want to learn how to add Freon to your A/C unit, then you're in the right place!

In this guide, you will learn:

  • How to add refrigerant to AC units
  • Why your A/C may need Freon
  • What type of refrigerant your system needs
  • And more!
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"Freon" is a term used when talking about the refrigerant used in an air conditioner.

What some people may not realize is that Freon is actually the brand name given to one refrigerant in particular: HCFC-22 or R-22. 

The EPA stopped production of Freon in January 2020 (and new AC units stopped in 2010) because it depletes the ozone layer and has a global warming potential of 1815. To put that into perspective, carbon dioxide (CO2) has a global warming potential of 1.

What does this mean?

Although production has been banned for almost 3 years, some recycled Freon and old stock is still available. There are also alternative refrigerants that can be used in place of it. 

New refrigerants can't be mixed with the old, but your system can be evacuated and alternatives can be used to keep your system running. At the end of the day, you have to look at your options and decide what's best for you and your system.

Keep reading to learn how to put freon in an AC unit in 11 steps!

What You Need To Know Freon For AC Units?

One of the first things to know is that in most cases an EPA certification is required to purchase and handle refrigerants.

The environmental issues as well as the potential hazards in handling refrigerants is why a certification is required. Freon is a high pressure gas that boils at around -40F at atmospheric pressure.

If improperly handled, serious injury can occur.

Why Does Your A/C Need More Freon?

As a licensed HVAC contractor, this is a question I get all the time.

Your A/C is a closed loop between the indoor evaporator coil and the outdoor condenser. Because it's closed, there should never be a need to add any additional refrigerant.

If a technician tells you your system is low, or needs to be charged, it has to be a leak. If the leak is not found and fixed, your unit will continue to leak and more Freon will have to be added in the future.

In most cases, its best to find the leak before recharging your system to prevent additional issues down the road as recommended by the EPA.

Supplies & Tools For Replacing Freon In AC Unit

  • Proper Safety Equipment - Gloves, Safety Glasses, Long Sleeve Shirt
  • Refrigerant Gauges - Used to measure refrigerant pressures while the system is running
  • Refrigerant Scale - Used to keep track of how much Freon is being added to your unit
  • Tank of Refrigerant - Make sure you have the correct refrigerant for your specific unit
  • Temperature clamp - Used to measure suction line and liquid line temperature
how to put freon in ac unit

It is necessary to keep track of the liquid and suction line temps when putting in Freon.

How To Add Freon To AC Unit (11 Steps)?

  1. Determine If Your HVAC System Is Blowing Air
  2. Select And Purchase The Proper Refrigerant
  3. Wait For The Right Temperature
  4. Use Proper Safety Equipment
  5. Make Sure You're Comfortable Proceeding!
  6. Turn Off Power
  7. Connect The Refrigerant Gauge
  8. Connect The Temperature Clamps
  9. Turn Power Back On & Monitor
  10. Open Left Side Valve
  11. Store The Remaining Refrigerant For AC Unit

Step 1 - Determine If Your HVAC System Is Blowing Air

Before adding additional Freon, always make sure your indoor blower is moving air through your duct.

Check your air filter and make sure there's no ice or frost on the evaporator coil. The evaporator coil is the section of the A/C inside with the air handler or furnace. If there's ice or frost, it has to thaw before you can accurately add the proper amount of refrigerant. 

Set the fan to "on" and turn the A/C "off" to help thaw the evaporator coil if necessary.

Read Also >> What Are The Highest Rated A/C Coil Cleaners?

Step 2- Select And Purchase The Proper Refrigerant

Check the rating plate on the outdoor unit to make sure you are using the correct refrigerant.

These refrigerants have different pressures and temperatures and cannot be mixed. If the wrong refrigerant is added it can be a costly mistake. The system would have to be evacuated and flushed by a professional and it may even have to be replaced if too much damage is done.

The most commonly used refrigerants are:

  • R22 (Freon)
  • R410A (Puron)

If you aren't sure what your unit uses, call a technician or contractor and have them check for you.

As I stated above, a certification is usually required to purchase refrigerants. Depending on your area, a vendor may ask you to see your certification and you may have to go through a licensed contractor.

Step 3 - Wait For The Right Temperature

Outdoor temperatures need to be 60 degrees Fahrenheit or higher to accurately check system pressures.

Low outdoor temps will cause pressures to read on the low side and you can accidentally overcharge your unit.

Step 4 - Use Proper Safety Equipment

Make sure you use the proper safety equipment to handle Freon.

It can be dangerous to inhale and will burn your skin if you're exposed to it. I've been burned by it before, it can happen quickly and without warning.

Always wear gloves and safety glasses to prevent accidental injury. Long sleeves would be a good idea as well.

Read Also >> How To Prevent Mold In Air Conditioners?

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Step 5 - Make Sure You're Comfortable Proceeding!

Make sure you're 100% confident in moving forward.

Freon is dangerous and can even be deadly. There are trained professionals that do this every day and would have no issue taking care of this for you.

Following these steps and using some common sense will definitely help keep you safe, but accidents do happen and you should only continue if you're certain you can handle it.

Step 6 - Turn Off Power

Turn power off to the outdoor unit by shutting off the breaker or pulling the service disconnect.

The disconnect is usually a gray metal box with conduit running to it from the unit. Once the power is off, you can proceed to hooking up the gauges.

Step 7 - Connect The Refrigerant Gauge

The refrigerant gauge should have three hoses.

Typically the left side is blue, the middle is yellow, and the right side is red. The left side is called the suction side and should be hooked up to the port on the larger of the two copper lines at the outdoor unit.

The right side is called the liquid side and should be hooked up to the port on the smaller of the two copper lines. The middle hose should be connected to the refrigerant tank.

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Professional digital temperature gauges. Homeowners for DIY use would likely use analog temperature gauges.

Read Also >> Our Top Picks For HVAC UV Lights To Prevent Mold

Step 8 - Connect The Temperature Clamps

Place the temperature clamps on both copper lines to read suction line and liquid line temperature.

These temperatures are used to measure superheat and subcooling values, which are necessary to know when the system is charged properly.

Step 9 - Turn Power Back On & Monitor

Restore power to the outdoor unit and allow it to run for about 10 minutes. Place the tank on the refrigerant scale to keep track of how much you're putting into the unit.

Step 10 - Open Left Side Valve

Open the left side valve on the gauges to allow refrigerant to enter the suction line intermittently and watch the pressures and temperatures.

Continue doing so until the measurements match the manufacturers specifications, which are typically listed on the rating plate or door of the unit. 

Step 11 - Store The Remaining Refrigerant For AC Unit

Follow the instructions that come with your Freon tank for proper storage. Again, these refrigerants can be dangerous and must be handled properly.

Read Also >> Check Out Pictures Of Mold In HVAC Air Ducts

Frequently Asked Questions 

Can I Add Freon To My A/C Myself?

Yes, as long as you take the necessary safety precautions, have the right equipment to take proper measurements, and can legally procure the correct refrigerant for your unit.

How Much Does Freon For Air Conditioners Cost?

The cost of R-22 refrigerant varies widely. Because it's out of production, some places can list it for extremely high amounts. If you're buying it yourself, you'll have to buy the entire tank, which can cost upwards of $1000. If a contractor has refrigerant left and is willing to charge your system, its typically $100-$150 per lb.

How Do I Know If My Freon AC Is Low?

Most of the time, you'll know because it isn't cooling. There's usually ice on the evaporator coil and you may even hear a hissing sound. If the indoor and outdoor units are both running, and the system isn't keeping up, it's probably low.

Is Freon Banned?

The production of Freon for AC units production was banned in January of 2020. The refrigerant is hard to come by, but in some areas it is still available. Alternatives are also available and a technician should be able to steer you in the right direction for what could be used in its place if this refrigerant isn't available to you.

Read Also >> How To Know If The Condensate Pump Is Properly Running For Your A/C Unit?

Final Thoughts On Freon For HVAC Systems

If your system needs more Freon, there's most likely an underlying problem, like a leak.

Make sure you fix all other problems before recharging your system, so that you don't have to keep adding more and more. Always check your systems rating plate to make sure you're using the proper refrigerant and use the proper safety equipment to prevent accidental injury.

As stated by Energy.gov, any undercharging or overcharging of your HVAC system can damage it.

And, if Freon isn't available, ask about alternatives. Most of the time it's less expensive than replacing the entire system. 

Thanks for taking the time to read this article! 

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