Homeowner Articles Common Causes of AC Refrigerant Leaks and How to Avoid Them

Are you experiencing reduced cooling or a completely non-functional air conditioner? One possible cause of these problems could be a refrigerant leak in your AC system. AC refrigerant leaks can be a frustrating and costly issue for homeowners, but fortunately, they can be prevented and repaired with proper maintenance. In this article, we’ll discuss some common causes of AC refrigerant leaks, ways to detect and diagnose them, and how you can avoid them for good.

Understanding AC Refrigerant Leaks

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Before we dive into the causes and prevention strategies of AC leaks, it’s important to have a basic understanding of what refrigerant is and why it’s important for your air conditioner’s functionality:

  • Refrigerant is a substance that is used in air conditioning systems to absorb heat and transfer it outside, thereby cooling the indoor air.
  • It is a critical component of your air conditioning system that helps to absorb and release heat in order to cool your home.
  • As the refrigerant moves through your AC system, it undergoes a phase change from a liquid to a gas and back again, allowing it to remove heat from the indoor air and transfer it outside.
  • Your air conditioner relies on a specific amount of refrigerant in order to function properly and efficiently.
  • Refrigerants are classified by the Environmental Protection Agency (EPA) as either “ozone-depleting” or “non-ozone-depleting.”
  • The most common refrigerant used in air conditioning systems today is R-410A, which is a non-ozone-depleting refrigerant. However, older air conditioning systems may still use R-22, which is an ozone-depleting refrigerant that is being phased out due to its harmful effects on the environment.

Signs of a Refrigerant Leak

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If your AC system is low on refrigerant, it can cause a variety of problems.

Some common signs that you may have an AC refrigerant leak in your air conditioning system include:

  • Reduced cooling or complete lack of cool air
  • Increased indoor humidity levels
  • Increased energy bills
  • Hissing or bubbling noises coming from the indoor unit
  • Frozen evaporator coils
  • Water pooling around the indoor unit

Reduced cooling or complete lack of cool air is one of the most obvious signs of a refrigerant leak. If your air conditioner is blowing warm air or is not blowing cold air or any air at all, it could be a sign that there is a refrigerant leak. This is because the refrigerant is responsible for absorbing the heat from the indoor air and transferring it outside. If there is not enough refrigerant in the system, it will not be able to cool the indoor air effectively.

Increased energy bills can also be a sign of a refrigerant leak. When your air conditioner is low on refrigerant, it has to work harder to cool your home. This means that it will use more energy and result in higher energy bills.

Hissing or bubbling noises coming from the indoor unit can also be a sign of an AC refrigerant leak. This is because the refrigerant is under pressure and can cause these types of noises when it escapes from the system.

Frozen evaporator coils are another sign of an AC refrigerant leak. When there is not enough refrigerant in the system, the evaporator coils can freeze over. This can cause your air conditioner to stop working altogether.

Water pooling around the indoor unit is also a sign of a refrigerant leak. When the evaporator coils freeze over, they can cause the condensation that is normally collected in the evaporator coil drip pan to overflow and leak out of the unit.

Common Causes of AC Refrigerant Leaks

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Now that we’ve covered the basics of refrigerant and how to identify a serious coolant leak, let’s take a closer look at some of the common causes of air conditioner refrigerant leaks.

Wear and Tear on AC Components

Over time, the natural wear and tear on your air conditioning system can cause it to develop leaks.

This can include the refrigerant lines, coils, and fittings. As parts become worn, they can develop cracks or holes, allowing refrigerant to leak out. One of the most common areas for wear and tear to occur is the refrigerant lines.

These lines are responsible for carrying the refrigerant from the compressor to the evaporator coil and back again. They are typically made of copper or aluminum, which can become brittle over time. As a result, they may develop tiny cracks or pinholes that allow refrigerant to escape.

In addition to the refrigerant lines, the coils and fittings in your air conditioning unit can also become worn over time. The coils are responsible for absorbing heat from the air, while the fittings connect different parts of the system together. If these components develop cracks or holes, they can also allow refrigerant to leak out.

Corrosion of Metal Parts

If your AC system is located in a humid environment, it may be more prone to corrosion. This can cause metal parts of the system to rust or corrode, eventually leading to leaks.

The most common metal parts to corrode in an AC system are the refrigerant lines and coils.

These components are typically made of copper or aluminum, which are both susceptible to corrosion. When these parts corrode, they can develop small holes or cracks that allow refrigerant to leak out.

Damaged or Improperly Installed Connections

During installation or maintenance, it’s possible for connections between different parts of your AC system to become damaged or improperly secured. This can cause refrigerant to leak out over time.

One of the most common causes of damaged connections is over-tightening. When connections are tightened too much, it can cause the metal to warp or crack, leading to leaks.

In addition, connections that are not properly secured can also lead to leaks over time.

Manufacturing Defects

In some cases, defects in the manufacturing process of your air conditioning system can lead to leaks. This can include issues such as faulty soldering or defective parts.

If your AC system was manufactured with a defect, it might be more prone to developing leaks over time. For example, if the soldering on the refrigerant lines is not done properly, it can cause tiny cracks to form that allow refrigerant to escape.

Overcharging the System

If too much refrigerant is added to your AC system during installation or maintenance, it can create excessive pressure and cause leaks in the system.

When an AC system is overcharged, it can cause the pressure inside the system to become too high. This can cause the refrigerant lines and other components to become stressed, leading to cracks or holes that allow refrigerant to escape.

How to Detect AC Refrigerant Leaks

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If you suspect that you have an air conditioner refrigerant leak, it’s important to have it diagnosed and repaired by a professional HVAC technician.vNot only can an HVAC refrigerant leak lead to decreased efficiency and increased energy bills, but it can also be harmful to the environment and your health.

Here are some of the methods that may be used to detect a refrigerant leak:

Visual Inspection

A technician may visually inspect your AC system for signs of refrigerant leaks, such as oil or debris around fittings, coils, or other parts.

They may also look for signs of corrosion or damage to the system that could lead to a leak. In addition to checking the AC unit itself, the technician may also inspect the refrigerant lines and connections to ensure that everything is properly sealed.

Electronic Leak Detectors

Electronic leak detectors can be used to detect leaks by sensing changes in the air or gas around your AC system.

These detectors are highly sensitive and can detect even small leaks that may not be visible to the naked eye. The technician will use a handheld device to scan the AC system and pinpoint the location of the leak.

Ultraviolet Dye Leak Detection

A special dye can be added to your AC system which will glow under UV light if there is a refrigerant leak present. This method is particularly useful for detecting small leaks that may be difficult to find with other methods.

Once the dye is added to the system, the technician will use a UV light to inspect the AC unit and identify any areas where the dye is present.

Soap Bubble Test

A technician may perform a soap bubble test by applying a solution of soap and water to potential leak points and watching for bubbles to form where there is a leak.

This method is a simple but effective way to detect leaks and can be used in combination with other methods to confirm the presence of a leak. The technician will carefully inspect the AC system and apply the soap solution to any areas where a leak is suspected.

In conclusion, if you suspect that your AC system has a refrigerant leak, it’s important to have it diagnosed and repaired as soon as possible.

A professional HVAC system technician can use a variety of methods to detect and locate the leak and then make the necessary repairs to ensure that your AC system is running safely and efficiently.

Preventative Measures to Avoid AC Refrigerant Leaks

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The best way to avoid costly and frustrating leaks is to take preventative measures to maintain your system.

Here are some strategies to keep your air conditioning system leak-free:

Regular Maintenance and Inspections
Scheduling regular maintenance and inspections from an HVAC professional can help to identify and prevent potential leaks in your AC system. This includes checking refrigerant levels and inspecting components for wear or damage.

Proper Installation and Repairs
Ensuring that your AC system is installed and repaired by a qualified professional can help to ensure that all connections are secure and parts are installed correctly.

Using High-Quality Components
Choosing high-quality AC components can help to prevent leaks and extend the lifespan of your air conditioning system.

Monitoring Refrigerant Levels
Regularly monitoring your AC system’s refrigerant levels can help prevent leaks and ensure your cooling system is functioning efficiently. If you suspect a leak, immediately contact a professional HVAC technician to diagnose and repair the issue.


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Refrigerant leaks can be a costly and frustrating issue for homeowners, but there are a variety of preventative measures that can be taken to avoid them. By understanding the common causes of your AC units’ leaks, detecting and diagnosing them early, and taking steps to maintain your AC system, you can keep your home cool and comfortable all summer long.

If you need a reliable and professional HVAC professional to check out your AC and keep it running smoothly all summer long, keep your cool with Upstate Home Maintenance Services.

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