Freon Leak Detector: Everything You Need to Know

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Last updated: 
June 14, 2019

If you think you need a Freon leak detector, then our guide will help you determine which one meets your prerequisites. Prolonged exposure to Freon can lead to lung fluid buildup, lung failure, heart issues, brain damage, and even death. If your HVAC unit is placed outside and you think you are safe from all these risks, think again, since it can easily enter your home.

It’s true that Freon is a heavy gas and will pool at ground level, but this still means it’s hazardous for children and pets. In addition, a refrigerant leak can raise your energy bills as much as 35%. Here are the main types of Freon leak detectors and their advantages and disadvantages:

an example of a freon leak detector

Professional Freon Leak Detectors:
Types and Features

Before jumping into the whole refrigerant leak detection equipment discussion, we want to mention that “Freon detection” generally refers to identifying all types of refrigerants.

Here are the most common and the most efficient methods to detect Freon leaks:

Liquid Detector

You can easily create a liquid Freon leak detector at home, by mixing soap or laundry detergent with water. Apply the resulting substance on piping and wait for bubbles to appear. That means you localized the leak and can proceed to seal it tight. This method is widely used by amateurs and professionals. However, you can also purchase liquid Freon leak detectors that are ready-made.


  • Very cheap.
  • Easy to make and use.


  • Not suitable for inaccessible spaces.
  • Not as accurate as other methods.
  • The ready-made ones have little to no advantages over homemade ones.

Note: Soapy solutions are best used together with other detection methods.

If you already tried it and didn't consider the old soapy water a reliable Freon leak detection method, you have a few other options available. These are manufactured and designed specifically for this purpose, thus being reliable and precise.

Infrared Detector

These devices use infrared sensors to detect any refrigerant leaks in your home. They smartly use refrigerants’ different reflectivity to infrared radiation to give accurate results in real time. An infrared Freon leak detection device has an accuracy of +/- 1.8°F for temperatures between 32 and 212 degrees Fahrenheit.


  • Instant results.
  • Can detect R404A, R407C, R410A, R134A, R417A, R422A, R507A, R143A, R125, and R245fa refrigerants.
  • Highly accurate if used within their maximum efficiency temperature range.
  • No risk of false positives due to moisture, oil, or gas leaks.
  • Can be used within a minute from starting the device.


  • Naturally, it cannot be used to detect leaks from areas that are not visible.
  • Their accuracy drops in environments colder than 32 and hotter than 212 degrees Fahrenheit.
  • They are almost useless in environments colder than -4 or hotter than 932 degrees Fahrenheit.

Electronic Detector

There are 2 types of electronic Freon leak detectors available: Negative corona and heated diode devices. Negative corona Freon leak detectors create a high voltage electric arc that is sensitive to refrigerants. When the electric corona detects Freon leaks, the device rings an alarm to let you know.  Heated diode Freon leak detectors use heat to break refrigerant molecules apart into Fluorine and Chlorine ions, which can be detected by heated diodes.

These devices have been around for a few decades, and impressed professionals from the start with their accuracy and newer models are much more precise.


  • Can detect leaks in inaccessible areas.
  • They are more precise as technology advances.


  • Negative corona electronic Freon leak detectors can malfunction in areas with high concentrations of refrigerant. This has been a problem ever since the beginning and, although significant progress has been made, it can still affect their functioning today.
  • False alarms are also likely when other chemicals are present in the air with both types of electronic detectors.
  • They have a fairly short range.

Fluorescent Dye Detector

Many professionals choose light-responsive dyes instead of soapy solutions to detect Freon leaks. These can be injected into the refrigeration system and is carried by the refrigerant through piping. Then, you can use a UV light to see where the dye leaked out of the system. This method is considered the best Freon leak detector at the moment.


  • Highly accurate.
  • They are not affected by other chemicals.
  • No false positives.
  • They pose no health threats.


  • They cannot be used for larger industrial systems or car ACs since visibility is a must.
  • Depending on the size of your system and the diameter of the puncture, it can take up to a few hours or even days to see results.

Halide Torch as a Detector

Halide torches can be used to detect Freon leaks. Chlorine-based refrigerants will change the flame’s color from blue to green. They use a probe hose to draw in air, which is then exposed to a copper reactor plate that has been previously heated.


  • This method shows instant results.
  • Halide torches make it easier to locate leaks.


  • It can only detect CFCs (chlorofluorocarbon-based refrigerants) and HCFCs (hydrochlorofluorocarbon-based ones).
  • It uses an open flame, which can be dangerous in some environments.
  • Many things can interfere with their accuracy: Wind can make it impossible for the device to collect the gas, thus leading to false negatives.
  • In addition, direct sunlight can make changes in the flame’s color hard to observe.

Ultrasonic Detector

These detectors are high precision systems that detect seal failures and pipe punctures in compressed air and gas systems. An ultrasonic leak detection device identifies the high-frequency noise refrigerants produce when leaking. They can accurately detect leaks up to 65 feet away and make it easy to identify the source thanks to an integrated point sight.

In addition, they can use a laser pointer to accurately detect leaks in areas with restricted access. Many have a transparent reflector, which offers precision without obstructing visibility.


  • Equipped with a highly-sensitive detection sensor.
  • Extremely precise in localizing the Freon leak thanks to visual stimuli.
  • Long-distance Freon leak detection.


  • Their accuracy is not satisfactory when used in noisy environments. Although many have features that prevent background noise from interfering with the results, it still affects the final result.

Note: Ultrasonic refrigerant leak detectors can be used together with a soapy solution to increase their precision. The sound of bubbles bursting will be easier to detect by these devices.

Other Tips & Tricks

If none of these methods identified a Freon leak, you seem to be safe. However, if you still suspect something might be wrong with your appliance’s refrigerant piping, you can perform a pressure test. For this, you will need a tank of pressurized dry nitrogen. It should go without saying the gas should be oxygen-free, but we want to highlight this aspect anyway. If you use a soapy solution, a 10-bar nitrogen flow should be enough to make the liquid bubble up.

In addition, keep the following in mind:

  • Never stop investigating after finding a leak. Check the whole system since leaks and punctures are most often caused by wear.
  • Choose high-quality piping and joints. These are less likely to wear out and will last longer.
  • Cap all valves. Uncapped ones are the most common source of refrigerant leakage.
  • Never place appliances that use refrigerant in unstable areas. Vibrations, physical shock, or chafing will deteriorate the piping which will, in time, start to leak.
  • Never ignore maintenance or try to reduce costs by choosing cheap repair services. You might get lucky by avoiding maintenance and professional repair services, but not for long.

Choosing the Best Leak Detector

Keep the below in mind to ensure you get the best value from the freon leak detector.

Detecting the Types of Refrigerants

To find the most suitable leak detector, one has to determine the refrigerant types to handle. That machine has to detect all of the refrigerants. The important thing to remember is that a detector that can detect many refrigerants can cost more than the ones that identify leaks of common refrigerants. Checking one's field application and expertise is important for that.

Working Speed

Everybody knows that time is money. Spending a lot of time on finding leaks with an inappropriate detector will frustrate the buyer and waste their time, so identifying leaks immediately is crucial. The buyer should choose a model that has good-quality sensors, has less warm-up time, as well as features that quickly detect the leak. Choosing the top brands is the safer option, as opposed to risking time for money on the cheap brands.


Detectors come with different types of sensors to identify the leak in the HVAC system. The best detector comes with good sensor quality and durability. The better the quality of the sensor, the higher the price.


The battery of the detector is another crucial aspect that buyers must examine. Having a good detector is useless if the battery lasts for a short period. The minimum prescribed time for a battery to last is a full day so that the user can get the job done efficiently. Modern leak detectors contain rechargeable batteries, helping the buyer save money and time from frequently purchasing new ones.


A broken detector won't help anyone, so make sure that the leak detector contains a warranty. Although top brands provide good-quality HVAC tools that last for a long period of time, the buyer needs to determine the warranty period since the detector can malfunction. It happens even to the top brands.

Freon Leak Monitoring Systems

If you want to make sure a future refrigerant leak will not go unnoticed, a multi-point refrigerant monitor is what you need. These use audio and visual signals to let you know when a leak has been detected. Here’s what to keep in mind when looking for a permanent refrigerant monitoring system:

  • The refrigerants your appliances use should be the most important factor. You don’t want to end up with a device that only detects CFCs and HCFCs when your fridge has HFC.
  • The device’s placement should be the next aspect you think about. The main unit should be placed in a highly visible spot in your home – like the hallway. At least one sensor should be right next to the appliances that use refrigerants.
  • Keep in mind that air conditioners or heat pumps with fans will direct the air in a certain direction.

Freon Leak Detector Final Thoughts

Please don’t try to install these devices by yourself unless you are a specialized technician. Your family’s health and lives are at stake, so cutting corners should not be an option with a freon leak detector. Never hesitate to reach out to us. You can email us with your questions or queries.

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