Reusable or Single-Use? Which Rapid RH Sensor is For You?

Smart Systems, Smart Sensors, Smart Choices is more than just a clever-sounding tagline; it represents a new way of thinking with the Rapid RH®. With the introduction of the 5.0 reusable Smart Sensor, Wagner Meters is also introducing the concept of Smart Choices: Customers should be able to choose which model is the fastest, the easiest, and the lowest cost per test for their particular situations.

As you’re considering the options, it may help to run through a comparison of single-use and reusable relative humidity (RH) sensors.


Rapid RH® L6 Smart Sensor

Even though the L6 is referred to as “single-use,” it is not removed or discarded after taking a sensor reading. Once placed in a test hole, the Rapid RH® L6 Smart Sensor is neither removed nor unnecessarily handled and is always equilibrated. The sensor continues to be functional, and moisture conditions can be monitored over an extended period of time if desired.


  • Most accurate and lowest cost per test when compared to calcium chloride (MVER) and other RH testing methods. The L6 can save more than 100 hours of labor and wait time over the less accurate MVER test.
  • Fastest model for RH testing. There is very little site prep required for this sensor. Once the test hole has been drilled and cleaned out, the sensor is placed in the hole, covered, and allowed to equilibrate, or acclimate. Once equilibrated, the reading is taken and recorded, then the hole is covered. If the slab is not ready, test readings can be repeated, without having to go through the process of placing sensors, equilibrating, etc. Time savings are built into the L6; there is no cleanup, no calibration checks, and no time spent removing the sensor.
  • Easiest model to use for ASTM F2170 compliance. Each test location has its own sensor, which comes with a NIST-traceable certificate of calibration. If paperwork is not your thing, the L6 removes the need for calibration checks and extensive record-keeping. Just record the location of the sensor on a test location map, then file it in a safe place with the NIST-traceable certificate of calibration that came in the box with the sensor, and your compliance paperwork is done.

Who might benefit from the L6 single-use?

  • If you believe that “time is money,” the L6 is likely the sensor for you. This sensor gives you the fastest, most accurate measurement of moisture conditions, allowing you to move on to the parts of your business that actually generate income for you.
  • If you don’t do a lot of concrete moisture testing, you should probably consider using the L6 when you need to test. ASTM F2170 requires reusable sensors to undergo annual recertification of their calibration, and you’ll need to add that cost into your cost-per-test calculations. If you aren’t doing many tests in a year, you could end up spending more per test for reusables than for the single-use L6.
  • Large jobs: Even with extremely affordable pricing on the reusable Rapid RH® 5.0, the cost of a reusable sensor inventory large enough to eliminate leapfrogging could be prohibitive.

Free Download – Which Rapid RH Sensor is Right For You?


Rapid RH® 5.0 Smart Sensor

Most people involved with concrete moisture testing are familiar with reusable sensors. As you’ll see in the following list, there are a number of disadvantages to conventional reusable sensors. After discussing the pros and cons, we’ll show you how the reusable Rapid RH® 5.0 Smart Sensor was designed to eliminate those disadvantages.


  • Cost per test goes lower every time the sensors are used. Buy the sensor once, and use it as many times as you wish (keeping in mind the annual recertification requirements noted below).


  • Additional time and labor costs: Obviously, the reusable sensor will have to be removed from the test hole, and stored for future use. A larger concern is the ASTM F2170 requirement that a sensor must undergo a calibration check within 30 days prior to any testing. This can take 1-3 hours per sensor.
  • Higher cost of equipment: Reusable sensors are more expensive than single-use, and many contractors will purchase a small number of sensors, then leapfrog them on larger jobs. Unfortunately, this also leads to skipping the equilibration step, which significantly reduces test accuracy.
  • Yearly recertification or replacement requirements: As mentioned above, ASTM F2170 requires reusable sensors to undergo annual recertification of their calibration or replacement with a newly certified sensor, so that cost must be factored into any cost-per-test or ROI calculations.

The reusable Rapid RH® 5.0 Smart Sensor eliminates most of the major disadvantages of reusable RH sensors:
Rapid RH 5.0 Smart Sensor

  • Lengthy calibration checks: Each 5.0 comes with its own EasyCare CalCheck — a protective base integrated with a consistent RH generator. The sensor is stored in an optimal environment, always equilibrated, and always ready for an instant calibration check.
  • Affordable pricing/leapfrogging: The initial cost of investing is now low enough that it’s possible to have a larger inventory of reusable sensors, removing the need for leapfrogging.
  • Be sure to check out the Rapid RH® annual recertification program.

Who might benefit from the 5.0 reusable?

  • Testing services: If you offer testing services, reusables make sense. The new time-saving features of the 5.0 will save you much more time and money.

Frequent testing, especially for larger jobs: If you do a lot of testing in the course of a year, then the reusable allows you to drive your cost per test to the absolute lowest possible and still retain accuracy. Also, the initial cost of inventory is low enough to remove any need to leapfrog sensors. Now you can afford to have all of the sensors you need to get the job done in one pass.


The Rapid RH® Smart Sensor L6 remains the standard for fast, easy, and low-cost concrete moisture testing. The new reusable Rapid RH® 5.0 eliminates the problems inherent in conventional reusable sensor design. Rapid RH® now has the Smart Choice for any application.

You choose.

Last updated on September 2nd, 2021

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