Can You Trust Digital Temperature and Humidity Indicators?

Is it time to upgrade your HVAC and refrigeration setup with a set of wireless digital manifold gauges? If you aren’t already, you should start.

These instruments are not required for competent HVAC work, but they do improve productivity and quality. To assist you to choose the correct digital HVAC gauges. I’ve outlined the features of the top models in this article.

Smart Testo Probes with Digital Measurements

Since they initially came out, I’ve been using Testo Smart probes. More advanced wireless Bluetooth capabilities may now be found in the newer, second-generation probes. Humidity-capacitive / NTC probes (605i), pressure probes (549i), and temperature clamps (115i) all have a claimed range of 350 feet. The wireless range for all other available accessories is 60 feet. This includes the Hotwire and vane anemometers, the manometer, the infrared thermometer, and the K-type thermometer.

Both the Testo Smart Probe app and the Measure Quick app are compatible with the Testo wireless digital gauges. Both applications do what they’re supposed to, but the measure fast app is packed with extras. You may use these instruments with up to six probes attached at once to swiftly determine a variety of system characteristics including superheat, sub-cooling, volume flow, etc. The program may be used to keep track of data and export trend logs to.csv or.pdf formats for easy sharing.


Extremely low price, the option to add more probes for a wider range of measurements, improved durability thanks to its second generation, user-friendly native software, and compatibility with the popular time and distance measuring tool Measure fast all add up to great value. Broad operating temperature range (58 to 302 °F), reputable Testo brand, and warranty. It may be difficult to get a new Teflon gasket for pressure probes given how long they last in comparison to a standard 1/4″ hose gasket. These digital HVAC gauges have been put through their paces and have come out on top.


Uses three AAA batteries yet has the same run time as probes that need just two. The Gen I devices had problems with Bluetooth communication and had no temperature correction for the pressure probes. Absence of an IP resistance rating.

Assembled manifold iConnect Probes

Of all of these digital HVAC gauges, the iConnect sensors are among the costliest. Is it prudent to invest in iConnect sensors? They were just too expensive at $1600, and the larger setup wasn’t worth it to me. The iConnect probes are fast and easy to use with the manifold software. Despite the fact that both the manifold and measure fast applications were created by Jim Bergman, Bergman has gone on record as saying that measurement quick’s in-app diagnostic tools are more reliable.

A maximum of 52 readings may be taken simultaneously from up to 12 separate wireless gauges when using a single Iconnect 900-c base station. However, the digital temperature gauges can only communicate data through the wireless pressure gauge by plugging into the latter’s radio receiver. Intent on minimizing manufacturing expenses, this was created.

Refrigeration multi-compressor circuit modules made to order are a notable addition. These digital HVAC gauges are the only ones on our list capable of keeping tabs on all of the refrigeration systems at once. While it is true that this function cannot currently be used with any MQ probest is being discussed as a possible future addition.


Exceptional build quality, Cooper-Atkins thermistors, a very extended operating range, and a number of independent refrigeration circuits.


When compared to the other digital gauges on this page, it is prohibitively expensive and cumbersome. They are also quite costly.

Smart Refrigerant Diagnostic Tool for the UEI Hub

Uei is taking too long to release its intelligent probes, and they ought to have ironed out the kinks first. The UEI Smart HUB2, HUB4, and HUB6 kits have generally been met with dissatisfaction from the people I’ve talked with. The software does not seem user pleasant, since it only offers the most fundamental computations and statistics and has a small library of just 44 different refrigerants. These HUB kits may now be used with the measure fast app.

The digital gauge probes have been criticized for failing after just a few usages, and some reports even claim they cease functioning entirely after only a few months. Unlike the connect probes, which are completely wireless on their own. The temperature clamp probes in this kit are wired to the pressure gauges and send data using the pressure gauges’ wireless components. If you’re really strapped for cash, this could work, but you’d be much better served saving up for one of the other digital gauge kits.


The HUB8 with an outside air sensor and micron gauge is expected to be introduced shortly, and it is cheap, easy to set up using Measure, and UEI is actively expanding and improving.


Bulky design, operating temperature range of just 32-176 °F, lack of comprehensive wireless operation.

Job Link Charge and Air Tool Kit, Field Piece JL3KH6

As with all of Field Piece’s HVAC equipment, the quality of their digital HVAC gauges for measuring refrigerant charge and air temperature is unmatched. These probes are excellent options because of their exceptional temperature and pressure precision and long-range Bluetooth that can transmit through most walk-in coolers and freezers.

Both the measure fast app and the native field piece app work with the JL3H6 kit. The native app is so bad that most people choose to utilize MQ rather.

The sensors are small enough to fit in a hardshell case and are built to withstand rough usage thanks to an IP55 designation that protects them from water.

Parker Set of Sporlan Smart Maintenance and Repair Utilities

There seems to be a lack of familiarity with the Sporlan SMART Service gauges compared to the others on this list. This kit has a tiny profile compared to the others; however, it comes with just four sensors. This set will have two wireless digital pressure gauges and two temperature clamps. It would seem that Sporlan does not provide any further probes as extras at this moment.

The Sporlan probes may be used with the measure fast app in addition to their own.

Some websites say that they are produced in the USA, but I can’t seem to track down any official documentation evidencing this.


Compact Sporlan item with durable Pelican carrying case and usable temperature range of -40 to 250 degrees Fahrenheit.


Wireless range of just 60 feet, hard-to-find CR2450 batteries, a hefty price tag, and fewer features than rival products.

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