Taking temperature readings is a fundamental part of any HVAC technician’s job, from studying air differences in the supply and return to reading super-heat and sub-cooling.
In this guide, we’ll walk you through some of the best HVAC thermometers sold today and explain how to select the right one for your job and budget.
What's In This Buying Guide
Best HVAC Thermometers
Fieldpiece makes the SPK2 durable compact thermometers for HVAC work, where this probe turns to fit into any pocket.
This HVAC thermometer is a little too heavy for a shirt pocket, but slips simply into a pants pocket.
It has a magnet that attaches to useful duct function and a screen that lights up when required.
It takes around a minute to obtain a reading but is a fantastic low-cost, reliable unit that works really well.
This is a fantastic thermometer to fast-check general temperature readings.
The Signstek 6802 is a digital thermometer that includes sensor probes to get accurate readings.
This is a budget unit built more for home use or part-time HVAC tech and works well enough for this use.
The Fieldpiece ST4 is an excellent digital thermometer built for the professional HVAC technician who will use a thermometer a lot.
The unit includes several attachments like clamps, one for liquid, and one for the suction line.
The Fluke 561 is an Infrared Thermometer created for the professional HVAC tech.
If you want to acquire temperature readings at a distance, this is a great choice.
It's a great tool for reading temperature on vents up high or low without needing to find a ladder out or kneeling down.
The REED SD-947 is another specialized HVAC thermometer that has many good features.
It reads a temperature range of -148 to +2372 Fahrenheit and quite accurate, +/-0.4%.
The display shows up to four temperature results in precisely the exact same time that comes in handy in various scenarios.
A very nice feature is that the real-time data logger that the data stored on an SD-card could be removed, stored, and copied.
What Are HVAC Thermometers?
Temperature measuring tools find the temperature of vapors, liquids, and solids.
Water, air, and refrigerant in copper lines measure the typical substance for temperature level.
Whatever the medium to be measured, the methods for evaluating the validity of the instruments are alike.
HVAC technicians should have thermometers that are accurate from -50°F to 250°F to measure outdoor temperatures, air flow, refrigeration lines, coolers, ambient temperatures and condenser lines.
In addition, they may need to measure the temperature of water temperatures as high as 220°F for ordinary service.
A variety of instruments may be needed to measure temperatures over 250°F - for example, flue gas analysis from the gas and oil-burning appliances, special thermometers are used.
In the past, most technicians relied more on glass than alcohol or mercury thermometers.
New Electronic digital thermometers, however, are what's used now and provide the most precise readings.
Digital Thermometers are easy, economical, and capable of taking measurements. Although the electronic instrument cost more, they could retain precision for longer times.
Pocket thermometers are often utilized in a pinch for taking quick a fast measurement but aren't as accurate as detector probes built into digital.
Accuracy is more significant than the lower temperature goes.
Where small temperature variations are measured. A 1°F air doesn't seem like much until you've one level off and or -1°F and attempt to have an exact temperature drop over the water heat exchange that just has a drop of 10°F. You'll have a built-in 20% degree of error.
How To Select A Best HVAC Thermometer
This depends upon the job. Pocket thermometers are an excellent tool to carry around and get general readings, like checking your Delta T, outside air temp, comfort calls, etc..
They do have some error but give an overall reading that point you in the right direction. Infrared thermometers are great in theory but usually do not meet the hype that encompasses them.
This may vary from company to company as to accuracy. An infrared thermometer can give an overall reading and are great in some instances. By way of instance, return air that's high up can get a fast general reading.
An infrared thermometer will not work well with copper lines that scatter the infrared detector, either.
Again, manufacturers have some great models out there, but infrared is mostly good for obtaining generalized readings, spotting thermal differences in a complex environment, and obtaining readings at a distance - in my experience.
The most precise reading you can get is using an electronic HVAC thermometer. The leads built into several HVAC meters like Fieldpiece HS33 are great multi-purpose temperature measuring equipment.
A specialized Digital thermometer with sensor probes are also a fantastic tool to use.
Last but not least is the sturdiness of your thermometer - it must hold up to all types of abuse that all HVAC technicians will put it through.
Remember, each instrument has its own place, and usually 2-3 kinds of thermometers are used depending upon the circumstance.
There are many great HVAC thermometers available, with a number of our favorite picks given above.
As always, make sure you read reviews on Amazon, HVAC tech forums and elsewhere to make sure a particular unit is the right fit for you.