How Do Infrared Refrigerant Leak Detectors Work?

Infrared refrigerant leak detectors are some of the most popular refrigerant leak detectors that are used by day to day professionals in the HVAC industry. Most green guys in the industry will buy one of the cheaper detectors on the market just to have one in their tool bag. Usually, it’s a heated diode detector that will have the sensor go out on them after working on a larger leak or after dipping the probe in water. (Yes, this happens.) Don’t even get me started on what kind a homeowner or do-it-yourselfer will purchase.

I am a huge fan of Infrared leak detectors for one reason and one reason only. Quality. These types of detectors scream quality and with quality comes long lasting and dependable tools. As I get older I’ve slowly come to realize that buying an expensive tool today is much better than replacing a shoddy tool again and again. Here’s the question though, how exactly does an Infrared detector work? What are the Pros and Cons of these types of products? Should you get an Infrared or should you look at maybe a Heated Diode or an Ultrasonic detector?

The How

Infrared detectors are quite a bit different than their heated diode competitors. With a heated diode they detect anything that contains Chlorine or Fluorine. When they detect a leak you can move the probe closer and closer until you have an exact pin-pointed location. This is what most techs and mechanics are used to in their day to day work.

Infrared refrigerant leak detectors find refrigerant by sampling an area in a slow an deliberate sweeping pattern. So, instead of moving your probe to the exact location you would sweep your probe back and forth or up and down until your alarm sounds.

While you can’t hold your probe still with an Infrared unit you will find, that after some re-training yourself, that you’ll be able to pin-point leaks even better due to the sweeping back and forth motion. The biggest advantage of Infrared detectors is that it will trigger the same regardless of what refrigerant it is coming across. This is quite a bit different when comparing to a heated diode that reacts differently depending on the type of refrigerant.

Pros & Cons

Jut like with everything else there are Pros and Cons to purchasing an Infrared refrigerant leak detector. Let’s dive in and take a look at what they have to offer:


  • The sensitivity levels on Infrared sniffers are top notch. Most of these models can detect leaks as low as 0.10 ounces per year. This is as good as it gets as far as sensitivity. I have yet to see any detector on the market today that goes under that magical 0.10 ounces per year number. Now, truth be told there are corona or diode models out there that do the same but there are much more benefits to an Infrared unit then just sensitivity.
  • You will notice that when shopping for an Infrared detector that the lifespan of a sensor is much much longer than your typical leak detector. While standard detectors on the market may have their sensors last for twenty, thirty, or fifty hours of work a Infrared detection unit will see it’s sensor last up to one-thousand hours. There are some units out there that claim their sensor will last for ten years. Imagine that, not having to change the sensor on your detector for ten years. You save yourself the hassle as well as the money. (Sensor replacement for other units can be as high as forty-dollars.)
  • Some users have stated that they had to relearn how to use an infrared detector when comparing to other more traditional detection methods like Corona Suppression or Heated Diodes. With the Infrared detection units you have to keep moving the sensor instead of letting it sit in one place. The reason this is necessary is the unit will zero itself out ever few seconds. The point of this to prevent saturation to your detector. So, if you’re in a tight or small room and there are multiple leaks it may be very hard to get a solid reading from your diode or corona reader not to mention you have the risk of overwhelming and damaging your detection sensor. With the Infrared though, since it zeros out ever few seconds, it will not be overwhelmed as it adjusts to the room and air around it and will look for higher concentrations of refrigerant allowing you to easily find the source of the leak.
  • As I said above, having an infrared detection unit may even negate the use of other methods as you’ll be able to track down exactly where the leak is using just your sensor. No more finding the general area and then spraying soap and water on it looking for bubbles. No more ultraviolet dye. With the infrared you should be good to go. Now, do keep in mind that there are always are surprises when diagnosing a unit and you very well may end up needing an alternative leak detection method in some cases. The point that I am trying to make here though is that the use of these other detection methods will drastically decline with the purchase of an infrared refrigerant leak detector.

The Cons

  • I mentioned at the beginning of my post that Infrared refrigerant detectors are top quality. Well folks with top quality comes top price. These types of units are the best detectors on the market today and you need to be prepared to pay that extra cash to own one. Most Infrared units are between three-hundred to four-hundred dollars a unit. Yes, I know it is quite expensive but the thing to keep in mind is the life span of this unit. If you’re a business owner with a whole bunch of techs under you then I could see why you don’t want to absorb the cost of these units, however if you are a tech who has to buy their own tools or an independent guy then I would highly recommend getting yourself an Infrared unit today. Forget the cost and just bite the bullet.
  • Every detector comes with a warranty, as they should. The reason I am putting warranties under the Cons category here is due to the length of the warranty and what most of them will uphold if there is a warranty claim filed. If you buy a unit you will notice that the warranty term is either one or two years. That is a pretty standard warranty claim for any detectors, even the cheaper ones. My concern is that if you spend all of this money on a top quality detector and for whatever reason you get a defective one but you are outside your one year warranty then you are most likely out of luck. Sure, you can try to call the company up and negotiate but they have all the chips in their corner at this point. If I’m going to be paying this much for a detector then I would expect at least a three to four, maybe even a five year, warranty.
  • The last con I can find on these units is a small one. It is a complaint about how you have to keep sweeping your sensor back and forth with an Infrared unit. I explained why this is necessary above but some users have complained that it is very difficult to do a sweeping motion in very tight or confined spaces. I could see this being an issue and maybe this is where more traditional detection methods could come into play such as dyes or a soap and water solution.

Recommended Infrared Detectors

Alright folks so we’ve gone over how these detectors work, the Pros & Cons, but now we need to review what we here at RefrigerantHQ recommend.

Whenever I recommend a product I always like to use the Good, Better, Best model. What is that? Well you see there are three different kinds of consumers or customers. There are the guys who want the cheapest thing there but still will work, the good; then there are the guys who want decent quality but they are a bit timid on the cost, the better; and then you have the guys who want the premium product, the best.

The problem here is that with Infrared detectors there really isn’t a low entry point or even a medium entry point. All of the comparable units are right around the same price and right around the same quality. At the time that I am writing this the three units that I would recommend are all right between three-hundred to four-hundred dollars. (Prices are subject to change at any time.) Instead of my usual approach of Good, Better, Best I am going to suggest to you the top three Infrared detectors on the market today. It will be up to you to make your decision from there. If you need some more input feel free to check out each product’s official RefrigerantHQ’s review by clicking on their links below.

Robinair 22791 Refrigerant Leak Detector

Robinair 22791 InfraRed Refrigerant Leak Detector

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Fieldpiece SRL2 (K7) Refrigerant Leak DetectorFieldpiece SRL2(K7) Advanced Refrigerant Leak Detector

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Inficon D-Tek Refrigerant Leak Detector

Inficon D-TEK 712-202-G1 Select Refrigerant Leak Detector

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In conclusion that is a brief synopsis of how the Infrared refrigerant detectors work, the benefits and drawbacks, and RefrigerantHQ’s recommended products. Thanks for reading and I hope that I was able to answer your question.