How to Check the Freon in a Home Air Conditioner

Below we’ll get into what freon is, how it works in an air conditioner and how to check your air conditioner for low freon levels.

Let’s get started.

What is Freon?

Freon is a type of refrigerant widely used in air conditioning units. It plays a critical role in the refrigeration cycle that enables air conditioners to cool your indoor spaces.

The evaporator coils in your AC unit absorb heat from the surrounding air, which causes the Freon to evaporate. This phase change from liquid to gas allows it to absorb heat efficiently.

Conversely, in the condenser coils located in the outdoor part of your air conditioner unit, the Freon is compressed and condensed back into a liquid state, releasing the heat it previously absorbed. Thus, the cycle continues, providing you with cool, comfortable indoor temperatures.

5 Signs Your Air Conditioner is Running Low on Freon

Keeping your air conditioning running optimally means keeping a close eye on your AC refrigerant level. Here are five tell-tale signs your air conditioner may be low on Freon:

  1. Increased Energy Bills: If your air conditioner is low on Freon, it will have to work harder to cool your space, leading to increased energy consumption and higher energy bills.
  2. Inadequate Cooling: If your home isn’t getting cool enough even when the AC is running, low refrigerant levels might be the cause.
  3. Ice on the Refrigerant Lines: Ice on the refrigerant lines or the outdoor unit could signal a Freon leak, leading to lower Freon levels.
  4. Hissing or Bubbling Noises: These sounds can indicate a Freon leak in your air conditioner unit.
  5. Frequent Circuit Breaker Trips: If the AC is continually tripping the circuit breaker, it could be due to low Freon levels, causing the AC unit to overwork.

5 Ways to Check if the Freon is Low in Your Air Conditioner

Checking your AC unit for low Freon levels can be done in several ways. However, always remember that regular maintenance by a certified HVAC professional is recommended.

  1. Visual Inspection: Look for ice on the evaporator coils and refrigerant lines, a clear sign of low refrigerant levels.
  2. Use a Refrigerant Slider: This tool can help you correlate the pressure and temperature of the Freon to see if they match the normal levels for your type of refrigerant.
  3. Check the Air Temperature: Measure the temperature difference between the air input and output. If the temperature difference is less than it should be, this might indicate insufficient refrigerant levels.
  4. Listen for Bubbling Noises: If you hear a bubbling noise from your air conditioner, this could indicate a refrigerant leak.
  5. Use Pressure Gauges: If you are knowledgeable about AC units, you can check the refrigerant pressure. Low pressure indicates a loss of refrigerant.

Should You Change Your Freon or Have an HVAC Professional Service Your AC?

While it’s important to monitor your air conditioning, when it comes to servicing your AC unit, it’s best left to the professionals. Working with refrigerants requires special certification due to the environmental impact and safety concerns associated with these substances.

HVAC professionals are equipped with the necessary knowledge, tools, and experience to diagnose and repair issues like refrigerant leaks or low Freon levels.

How Much Does it Cost to Refill the Freon?

The cost of refilling the Freon in your air conditioner can vary widely based on your location, the type of refrigerant your AC unit uses, the amount of refrigerant needed, and the HVAC contractor you choose.

However, it’s important to remember that if your AC unit is low on Freon, there’s likely a leak that needs to be addressed. Simply refilling the refrigerant tank won’t fix the underlying issue.


Understanding the role of Freon in your air conditioner, recognizing the signs of low refrigerant levels, and knowing when to call an HVAC professional can help you maintain a well-functioning AC unit.

Regular maintenance of your air conditioner unit not only ensures a comfortable indoor temperature but also helps you save on energy bills. Always remember, when dealing with refrigerants, safety comes first. So, when in doubt, call the professionals!

About Roy Cohen

Roy Cohen has a burning passion for heating, cooling, and ventilation. He aims to help you save money on expensive repairs and bring you the best HVAC products. He has years of experience behind him in HVAC repair and garage maintenance.

You can find Roy at his LinkedIn or his email: [email protected]

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