Signs of AC Freon Leaks and What You Should Do

Lydia Schapiro
Written by Lydia Schapiro
Updated April 3, 2023
A high efficiency modern AC-heater unit
Photo: galinast / iStock / Getty Images Plus / Getty Images


  • When an AC refrigerant leaks, your AC unit will be less efficient.

  • A common sign of an AC refrigerant leak is higher-than-usual utility bills.

  • There are some DIY fixes, but you may have to hire a professional. 

  • Common causes for AC refrigerant leaks include metal erosion and wear and tear.

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When your AC refrigerant leaks—a common homeowner issue—the appliance doesn’t work as effectively as it should. A “drip, drip” may sound daunting, but it’s actually a pretty common problem you can fix. From troubleshooting tips to warning signs, use this guide to learn how to identify and fix an AC Freon leak. 

What Is an AC Refrigerant?

AC refrigerant is a chemical compound used within an air conditioner. The refrigerant’s job is to absorb heat and provide cool air after running through the compressor and evaporator. Essentially, an air conditioner’s ability to cool your home is dependent on the AC refrigerant properly operating. 

What Causes AC Freon Leaks?

There are a few common reasons for AC refrigerant or Freon leaks, including:

  • Improper installment: When certain components and pieces are not secured, your AC may leak. 

  • Metal erosion: Metal erosion causes small holes to form, resulting in refrigerant leaks. 

  • Factory defects: If an AC unit leaves the factory defective, leaks may occur over time. 

  • Wear and tear: The rubber seals on the valve stems of AC units tend to wear out over time which can cause leaks. In addition, the outdoor components may accumulate rust, endure wear and tear, and lead to leaks. A broken Schrader HVAC valve could also cause refrigerant to leak.

Signs That Your Refrigerant Is Leaking

When your air conditioning unit is malfunctioning, you may not know how to diagnose the issue. Any one of these warning signs below could warrant a call to the pros. 

Higher Utility Bills

An AC that leaks is less efficient because it has to work harder to cool your home. This means you’ll probably have higher utility bills. If you’re noticing utility bills that are higher than usual for no apparent reason, this could be a sign of a Freon leak.

Longer Cooling Time

A less efficient AC unit won’t cool your house as quickly as usual. 

Increased Humidity 

Air conditioner units contribute to lowering the humidity levels in your home. If your humidity levels increase or fluctuate drastically, you may have a refrigerant leak. 

According to the Mayo Clinic, the ideal indoor humidity level is 30% to 50%, meaning the air contains 30% to 50% of the maximum amount of moisture it can hold.  

Hissing Sounds

Over time, metal might erode in your components, causing cracks or holes in the coils. If you notice hissing noises, you could have a leak that needs repair. 

If Your AC Refrigerant Is Leaking, Do This First

If you suspect you have an AC refrigerant leak, first things first, turn off the thermostat. When you keep a spewing AC running, you may cause more damage to the unit and release more refrigerant into your home.

How to Fix a Leaking AC Refrigerant

A technician air-conditioning repairman checking electric at circuit
Photo: Eakrin / Adobe Stock

A common cause for AC refrigerant leaks is that the condensate drain line is clogged. This component allows for condensation to escape the AC unit. If water builds up in the element next to the condensate drain line (the condensate drain pan), it can clog and leak over time. 

1. Access the Condensate Drain Pipe

To fix an AC leak, start by locating the condensate drain pipe, usually outside your home. Look for a white or copper pipe near the outdoor unit. Check your owner's manual if you have no luck finding the pipe. 

2. Clean Out the Pipe

Next, attach a dry or wet vacuum cleaner to the end of the pipe and use it to clean out any blockage. 

3. Replace the Filters

Still leaking? Try replacing the air conditioner’s filters. You’d be surprised how much debris and dirt accumulate on these filters, block airflow to the evaporator coil, and—you guessed it—cause leaks. 

4. Call a Professional

If the leak issue persists, contact a local AC repair pro equipped with the knowledge and tools to diagnose the issue and repair your AC unit. You can expect an AC service to cost between $75 and $200, depending on the type of AC unit and the size. 

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