Best AC Thermometers – 2021 Complete Review

A thermometer isn't the most exciting device, but it's one that is important in our lives. You use thermometers to take temperatures – in the HVAC world, temperature control is crucial.

Just a degree difference could represent a big change in the status of your equipment and compliance with certain regulations, such as the meat refrigerator at a supermarket. Precision is critical.

Taking an accurate temperature is essential for taking readings of subcooling, superheat, and air differences. AC thermometers are generally used to measure copper line temperatures, refrigerant, water, and air. All of these measurements are important in locating where a potential defect or hazard lies.

Comparison of the Best AC Thermometers

  • Non-contact as well as contact temperature measuring
  • Measures from 40 to over 1220 Fahrenheit
  • Very accurate readings with only 1 percent tolerance
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  • Temperature probe made from high-quality stainless steel for durability
  • Large easy to read display at a glance
  • Up to 8000 hours of battery life on a single AAA battery
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  • Best Digital AC Thermometer
  • Quite easy to use for temperature readings
  • Temperature probe made from high-quality materials for durability
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  • Best Car AC Thermometer
  • Easily reads from 0 to 220 degrees Fahrenheit
  • Protective cover for probe included
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How to Choose an AC Thermometer

A quality AC thermometer is useful when it comes to HVAC maintenance. Speed and accuracy are the top two must-haves for an HVAC thermometer, but consider the following as well:


Emissivity is a term used to describe the capacity of a surface to emit thermal radiation. Keep in mind that not all surfaces radiate the same infrared vitality. With this in mind, the best AC thermometer will be one that has settled or customizable settings that will take into account the different infrared vitality of each surface.

Fluke 561 HVAC Pro


An AC thermometer must be able to withstand the kind of work that is necessary for maintaining an air conditioning unit.


The best AC thermometer should display and record an object's temperature quickly. This helps you save time and will give you the best readings.


Accuracy is an important feature that an AC thermometer should have, especially when you consider the fact that you're working with expensive machines. The more accurate the thermometer is, the better the temperature reading will be.

Temperature Range

The best AC thermometer should have a good temperature reading range, which means that it should measure a wide range of temperatures.

Review of the Best AC Thermometers

Now that you know what to look for in the best AC thermometer, let's take a look at our favorite thermometers on the market today.

Best Overall:
Fluke 561 HVAC Pro

Fluke 561 HVAC Pro Infrared Thermometer, -40 to +1022 Degree F Range


  • Easy to use
  • Extremely durable
  • Adjustable emissivity
  • Infrared thermometer
  • Accuracy spec of +/- 1 degree


  • A bit pricey
  • Doesn't come with a clamp

What Recent Buyers Report

The Fluke 561 is incredibly easy to use infrared AC thermometer. You can quickly and accurately take readings of your AC unit without any temperature fluctuations. This product is accurate within one degree, which is much better than most other AC thermometers.

The only downsides are that it's a bit pricey and that it doesn't come with a clamp to hold the thermometer while you take temperature readings.

Why it Stands Out to Us

What stands out the most about this product is its accuracy and how easy it is to use. Using this infrared thermometer, you won't experience any temperature reading fluctuations while taking a temperature reading.

The Flue 561 is made from high-quality, durable materials, so you know that it will last you for years to come. Another great thing about the Fluke 561 is that it has adjustable emissivity, which is essential for AC thermometers.

Bottom Line

If you need an AC thermometer that's easy to use, durable, and has adjustable emissivity, you should consider getting this product. It doesn't come with a clamp to hold up the thermometer while you take readings, and it's on the pricey side, but you won't regret purchasing this thermometer.

Fieldpiece SPK2

Fieldpiece SPK2 Folding Pocket in-Duct Thermometer with MAX/MIN Hold and Stainless Steel Probe


  • Large display
  • Low battery alert
  • Auto shut-off feature
  • Compact with a folding feature
  • Economically priced for everybody's budget


  • No backlight
  • The response time is a bit slow

What Recent Buyers Report

The Fieldpiece SPK2 takes accurate and quick air temperature readings effortlessly. It has a foldable design, so you can easily put it in your pocket while you work, ensuring that you always have it handy. You'll also find that this thermometer has a hanging hook, so you won't lose it or misplace it.

Why it Stands Out to Us

This thermometer has a large display that is very easy to read, but it doesn't have a backlight. The temperature measurement range is quite large, ranging from -58 degrees to 392 degrees F.

It has an auto shut-off feature, which is perfect for conserving the battery of the Fieldpiece SPK2. You'll find that this product is priced to be fit into everybody's budget, so you won't feel like you're breaking the bank by purchasing such an important piece of HVAC equipment.

Bottom Line

The Fieldpiece SPK2 is reliable, accurate, and fast. It's a device that all HVAC technicians can use without any difficulty. Plus, you can easily keep it in your pocket thanks to the foldable design, and you can hang it up when you finish using it.

Best Digital AC Thermometer:
UEi Test Instruments PDT650

UEi Test Instruments PDT650 Folding Pocket Digital Thermometer,Yellow


  • Auto shut-off
  • Three-year warranty
  • Provides accurate readings
  • Can record minimum and maximum temperatures
  • Can measure temperatures from -58 degrees to 572 degrees F


  • Not very durable
  • Slow to take temperature readings

What Recent Buyers Report

The UEi Test Instruments PDT650 is a great digital thermometer because of all the features it offers. It has a wide temperature reading range, can fold into itself, has a magnetic mount, and a large display. It will provide you with reliable and accurate temperatures, but it does take a while to get those temperature readings.

Why it Stands Out to Us

UEi Test Instruments is a tried and trusted brand with years of experience in manufacturing and designing high-quality thermometers. This AC thermometer's versatility is incredible; you can use it for HVAC, refrigeration, and food services.

It comes with a built-in magnetic mount so you can hang it up on your fridge when you finish using it. The temperature range is also impressive for a digital AC thermometer.

Bottom Line

This thermometer is very reliable and accurate, and it's easy to store when you're not using it. It's very simple to use, and you can use it for other projects that require accurate temperature readings. While it might not last you years to come, it's definitely worth the money.

Best Car AC Thermometer:
InterDynamics TH-27

Interdynamics Certified A/C Pro Car Air Conditioner Test Thermometer, Helps Diagnose AC Performace and Checks Outlet Duct Temperature and Ambient Temperature, includes Holder and Clip


  • Easy to calibrate
  • Very accurate and reliable
  • Compact enough to carry around with you
  • Temperature range of 0 degrees to 220 degrees F
  • Checks duct temperature and ambient temperature


  • Can be difficult to read
  • Tick marks are every 4 degrees

What Recent Buyers Report

The InterDynamics TH-27 is the best automotive AC thermometer you're going to find. It does exactly what it's supposed to do and provides you incredibly accurate temperature readings right out of the package. The temperature reading range is vast for a car AC thermometer. However, this thermometer can be hard to read due to the small display.

Why it Stands Out to Us

For being a car AC thermometer, the InterDynamics TH-27 provides you with accurate and reliable readings. You can use this AC thermometer right out of the box and still receive an accurate reading. The temperature range is impressive as well, which is why it's the best car AC thermometer.

The recommended temperature range for your car's AC is highlighted in green so you can see it easily without having to guess where it should be. It's also very compact, so you can keep it on hand in your car for whenever an AC issue arises.

Bottom Line

The InterDynamics TH-27 is the best car AC thermometer that you're going to find on the market. You can use it right from the package and get an accurate reading. While you might have to calibrate it every once in a while, it's easy and quick to do.

5. Etekcity Lasergrip 774

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  • Auto shut-off function
  • Designed to be durable
  • Fahrenheit and Celsius reading options
  • Can take temperature readings from a distance
  • Will display the temperature reading for 15 seconds


  • Isn't always accurate
  • Can be difficult to aim

What Recent Buyers Report

This AC thermometer is very popular because it has a history of excellent performance. The Etekcity Lasergrip is a reliable, accurate, and versatile product that can read temperatures ranging from -58 degrees to 716 degrees F. However, it can be inaccurate at times, depending on the surface you're taking a read of.

Why it Stands Out to Us

The first thing that stands out to us is that it can display a temperature reading for 15 seconds before disappearing. This makes it so you can record the temperature changes easily.

Another thing is the temperature range because it's one of the largest ranges you'll find on an AC thermometer. The Etekcity Lasergrip also has an incredible temperature reading distance that makes it, so you don't have to be too close to the object you're measuring. 

Bottom Line

This product is a versatile and durable AC thermometer that will provide you with accurate readings without you needing to get too close to the object you're measuring. It's available at a reasonable price point for most people, and you can use it for various projects.

Are AC Thermometers Universal?

AC thermometers can be universal, but some aren't. If you go with an AC thermometer that is universal, you should be able to use it for more than HVAC systems (i.e., refrigeration systems).

This all depends on which type of thermometer you go with. For example, if you go with a car AC thermometer, that thermometer will only work your car's AC unit. But if you went with an infrared or digital thermometer, you should be able to use it for more than one purpose.

What Do I Need to Know Before Buying?

There are a few things that you need to know before buying an AC thermometer.

Not All Thermometers Equal

All thermometers are different. One AC infrared thermometer could have a wide temperature range, and another has a small temperature range. When you search for the best AC thermometer, keep this in mind, so you know to treat every thermometer as a separate item.

Fieldpiece SPK2

Expensive Doesn't Mean Accurate

While it's true that the more expensive a product is, the higher quality the materials are. But this doesn't mean that you have to go with the most expensive AC thermometer on the market.

Price isn't the feature that you want to define a thermometer by. Instead, think about what situations you're going to be working in and about the features you need.

Only Go with Features You Need

The last thing you want to do is go with an AC thermometer that doesn't have the features you need for the job you're working on. An example of this would be working with copper lines and having an infrared thermometer.

In this situation, you have a thermometer that will bounce off the reflective surface and give you inaccurate readings – you would be better off with a digital thermometer.

So, before you purchase an AC thermometer, the thing about what you're going to be using it for the most so you can narrow down the features you need.

Types of AC Thermometers

There are a few different types of AC thermometers that you'll run into when searching for the best AC thermometer. Below is a guide to help you understand the differences between the types of AC thermometers:

Dial Thermometers

This type of AC thermometer is very inexpensive and straightforward to use. They combine a stainless-steel probe, dial face, and bimetallic spring, and you can place it into the AC unit at key points. This type of thermometer does take a few minutes to stabilize and vary in accuracy. However, they are easy to calibrate if necessary.

You don't want to choose a dial thermometer if it has too large a temperature range; a smaller temperature range will provide you with a much more accurate temperature reading.

Digital Thermometers

Digital thermometers work very similarly to dial thermometers, but they have digital displays instead of a dial face. They do require batteries and can be a bit more costly.

Air Flow Thermometers

These AC thermometers have curved probes that air passes through to give you a quick air temperature reading. These thermometers aren't easy to insert into ductwork because they require a large opening.

Infrared Thermometers

These thermometers can take temperature readings from a distance and provide you with very accurate readings. However, you can't use them to take direct temperature measurements of the air.


AC thermometers are important tools for all HVAC technicians. While a good thermometer might come with a high upfront cost, they will provide you with the best temperature readings and ultimately save you time. When it comes time for you to choose your next AC thermometer, we hope that you remember the information in this article to make the best choice.

People Also Ask

AC thermometers are critical HVAC tools, so, understandably, people have questions regarding them. Below you'll find some of your questions answered for you to provide you with a better understanding of AC thermometers.

How Much is an AC Thermometer?

The price of an AC thermometer will ultimately depend on which type you go with. However, you can expect to find a price range from $7 to $200.

How Long Do AC Thermometers Last?

Again, this will depend on the type of AC thermometer you purchase and what it's made from. If it's made from high-quality materials, such as stainless steel, you can expect your AC thermometer to last for two to three years, longer if you take care of it. Plastic thermometers might last you a few months.