How To Put Freon in an AC Unit 2025: What You Need to Know

If your air conditioner isn’t cooling like it used to, low refrigerant could be the cause. In older systems, this often means the unit is low on Freon—a type of refrigerant that absorbs heat and cools the air. While newer units may use different refrigerants, many homeowners still wonder: How to put Freon in an AC unit, and can they do it themselves?

The answer is a bit more complex than a simple yes or no— In this guide, we’ll explain what Freon is, how to tell if your AC needs more, and what’s involved in adding Freon to an AC unit. Most importantly, we’ll cover why this task should be left to the pros!

Can You Put Freon in an AC Unit Yourself?

While technically, it is possible—legally, it IS NOT advised. Handling refrigerant, including Freon, requires EPA Section 608 certification. This is because Freon can be dangerous if mishandled and harmful to the environment if released improperly.

Adding Freon to an AC unit also involves more than just pouring something into a tank. It requires:

• Diagnosing a leak (refrigerant doesn’t just disappear)
• Repairing the leak before recharging
• Using proper gauges and equipment to measure pressure
• Ensuring the correct amount of refrigerant is added

Doing this incorrectly can lead to poor performance, system damage, or even personal injury. For these reasons, recharging an AC system is a job for a licensed HVAC technician.

What Exactly Is Freon?

Freon is a brand name for a class of refrigerants. Its job is to circulate through your AC system, absorbing heat from inside your home and releasing it outside. Without enough refrigerant, your system can’t cool the air efficiently—or sometimes at all.

Due to environmental concerns, certain refrigerants are slowly being phased out and are no longer produced in the U.S. However, many older units still rely on it, and some technicians can still service these systems using only recycled or stockpiled supplies, which, of course, all have an end-of-life limit as they are no longer being manufactured, and a regulated and mandated replacement has been set.

Signs You May Need to Put Freon in an AC Unit

Before putting freon into an AC unit, it’s important to recognize whether or not your system actually needs it. Here are the most common signs of low refrigerant:

• AC blowing warm or room-temperature air
• Longer cooling cycles or system running non-stop
• Ice forming on the refrigerant lines or evaporator coil
• Hissing or bubbling sounds from the unit (possible leak)
• Higher-than-normal energy bills
• Your home feels humid and uncomfortable

If you’re noticing a few of these issues, it’s possible your system is low on refrigerant.

How AC Professionals Put Freon in an AC Unit & What the Process Looks Like

Even though homeowners should never attempt this themselves, it helps to understand the process. Here’s a general breakdown of how a professional puts freon in an AC unit:

1. Confirm Refrigerant Levels Are Low

The technician will use pressure gauges and temperature readings to confirm that the refrigerant is low and that a recharge is necessary. They’ll also check for other issues that could be causing poor cooling.

2. Locate and Fix Any Leaks

Since refrigerant is sealed in a closed-loop system, it should never run out. If levels are low, that means there’s a leak. A tech will locate the leak, repair it, and make sure the system is sealed before adding any refrigerant.

3. Connect the Manifold Gauges

Next, they’ll connect a manifold gauge set to the service valves on the outdoor unit. This allows them to monitor refrigerant pressure and put freon in an AC unit accurately.

4. Add the Correct Type and Amount of Refrigerant

The Type and amount of refrigerant added to your air conditioning system are important. Using a certified refrigerant cylinder, the AC technician will add Freon to the AC unit slowly while monitoring the system pressure. They’ll adjust until the pressure and temperatures match the manufacturer’s specifications.

5. Test and Monitor the System

Once recharged, the tech will test the system to ensure it’s cooling properly and check for any remaining issues.

Why Only Experts Should Add Freon To Your Air Conditioner

We get it—DIY AC repairs can be tempting. But when it comes to how to put Freon in an AC unit, the risks outweigh the savings. Improper handling can damage your system, void your warranty, and even pose health risks. Plus, if your system still uses R-22 or even R-410A, you should strongly consider upgrading to a newer, more efficient model that uses modern refrigerants.

Final Thoughts On Putting Freon In An AC Unit

Understanding a professional’s process for how to put Freon in an AC unit is useful knowledge, but it’s not something you should ever attempt to do on your own. If you suspect your system is low on refrigerant, your best move is to call a licensed HVAC technician who can safely diagnose the problem, fix any leaks, and recharge the system if needed.

At Cruz Air & Electric, we offer expert AC repair, refrigerant leak detection, and Freon recharging services in Humble, TX, and the surrounding areas. We’re licensed, local, and here to keep your home cool—without the guesswork.

Need Freon added to an AC unit? Contact our local AC service team today at 281-446-4272 for fast, affordable maintenance and repair solutions.