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Delmhorst J-4 Moisture Meter
Our Score:
Delmhorst J-4 Moisture Meter

As with all pin meters, it can be very difficult to insert the pins far enough into hardwoods to obtain accurate readings. Attempting to do so often results in bent or broken pins. Also, short pins will not reach far enough towards the center of thicker slabs where higher moisture is found. According to the United States Department of Agriculture, boards should be read at a depth of one-fourth to one-fifth of its thickness.The Delmhorst J-4 is an analog pin-type meter that can be used for measuring moisture in wood and other building materials. This no-frills, basic meter performed well in our accuracy tests, except that it does not maintain its accuracy when surface moisture is present.

An optional slide hammer accessory is available for taking measurements at various depths. Adjusting for temperature and species requires the use of the correction tables in the manual.

Although this meter lacks some of the handy features of other wood moisture meters, its reasonable accuracy makes it suitable for many applications where a pin-type meter is preferred.


  • Better accuracy than most other meters.
  • Capable of being used with a variety of building materials.
  • Built-in calibration check.
  • Easy, two-button operation.
  • Ergonomically designed with sturdy construction.


  • Questionable pin durability.
  • Temperature and species adjustments require using a table.
  • Few extra features.
  • Range does not extend below 6%.
  • Surface moisture affects readings.

Objective Evaluation – Overall Score 3.7 out of 5.0

Objective test summary results for the Delmhorst J-4 Pin Analog wood moisture meter, achieving objective score of 73%

Accuracy – 4.5 out of 5.0

This meter provided reasonably accurate readings compared to ASTM D-4442 oven dry standards. The accuracy of the moisture content (MC) readings decreased at 23% and above.

Delmhorst J-4 Accuracy Test Results

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Surface Moisture – 1.0 out of 5.0

The Delmhorst J-4 provides significantly inflated readings when surface moisture is present, which indicates that operating this meter in high humidity environments where condensation may form on the surface could lead to questionable readings.

Bar chart showing the Delmhorst J-4 provides significantly inflated readings when surface moisture is present.

Learn about our surface moisture test procedures

Meter Temperature – 4.3 out of 5.0

Meter temperature had an effect on this meter’s readings when the temperature of the meter was high (110° F).

A low meter temperature of 34.8° F in the presence of low and high MC showed no change in the readings compared to the room temperature reading of 70.5° F.

A high meter temperature of 110° F in the presence of low and high MC, however, showed differences of 1% and 2%, respectively, compared to the room temperature reading.

Bar chart showing high meter temp impacted Delmhorst J-4 Meter readings

Learn about our meter temperature test procedures

Wood Temperature – 3.0 out of 5.0

Wood temperature had an effect on this meter’s readings.

A low wood temperature of 33.6° F in the presence of low MC increased 0.9% from the room temperature reading. In the presence of high MC, the reading increased 0.6%.

A high wood temperature of 110° F in the presence of low MC decreased the MC reading by 1.5% compared to the reading at room temperature while the high MC reading decreased by 3.8%.

Bar chart showing Delmhorst J-4 Wood Temperature meter readings were impacted by wood temp

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Reading Repeatability – 5.0 out of 5.0

The meter’s readings were highly repeatable.

Delmhorst J-4 Repeatability Test

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Drift – 5.0 out of 5.0

Readings with this meter showed no drift after 3 seconds.

Line chart showing the Delmhorst J-4 Pin analog wood moisture meter showed no drift after 3 seconds

Cable Interference – N/A

Unless an optional cabled accessory such as the slide hammer is used, the J-4 is not able to be tested for cable interference.

Delmhorst J4 cable test

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Subjective Evaluation – Overall Score 3.3 out of 5.0

Delmhorst J4 Subjective Review Summary

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Ease of Use – 3.8 out of 5.0

With only two buttons to push, one for calibration, and the other for obtaining the MC reading, this meter is easy to operate. Little use of the manual is needed except for using the tables to adjust for species and wood temperature.

Quality – 4.3 out of 5.0

Sturdy, durable construction. The meter itself is unlikely to break or malfunction with normal use. However, pin durability could have been better as we experienced problems with pin breakage during our testing.

Comfort – 3.5 out of 5.0

With an ergonomically-designed shape, this meter fits nicely in one’s hand. It is not compact enough to fit easily into a shirt pocket, but it does come with a hard case to protect the meter when transporting it from one job site to the next. The analog display is not the easiest to read when working in tight spaces.

Versatility – 1.0 out of 5.0

This is a single-mode meter (pin), which is typical. Readings on the display must be viewed upside down, which is not convenient, especially given this meter’s analog display. Capable of giving relative readings in a variety of building materials.

Range – 3.7 out of 5.0

The J-4 reads from 6% to 30% MC. It is not capable of taking measurements at very low moisture levels below 6%.

Features – 2.1 out of 5.0

Readings precise to the nearest 1%. This is a very basic meter with few extra features, but it does include a built-in calibration check. Lacks a HOLD function and low battery indicator. The meter can be used with either the built-in pins or an optional slide hammer accessory. Two types of contact pins are available: non-insulated, which should be pushed into the wood to their full length of a 5/16th inch, and insulated pins, which can be driven to the desired measurement depth.

Customer Service – 4.5 out of 5.0

Delmhorst customer service was knowledgeable, helpful and polite. The representative was able to answer all the basic questions about repairs, returns, etc. Fast response to both telephone and email inquiries. Manual available online.

Warranty and repair information:

  • One-year warranty on all Delmhorst meters, and a 90-day warranty for optional electrodes..
  • The meter must be physically inspected before the actual repair cost can be determined.
  • 3-5 business-day turnaround on repairs.

Our review is based on Moisture Meter Experts independent evaluation of the meter, which was purchased by Moisture Meter Experts or provided free of charge by the manufacturer. By purchasing this meter through the links above, Moisture Meter Experts may be compensated either by your purchase directly from Moisture Meter Experts or from commissions from an affiliate. View our Review Procedures section to learn more about our proprietary evaluation procedure and expertise in the field of moisture meters.