The Extech MO220 is a pin-style, conductivity moisture meter specifically designed for wood applications though it also measures moisture in other building materials.
It scored reasonably high in accuracy tests when measuring moisture content (MC) in the mid-range. However, this meter and its heavy duty probe accessory are incapable of taking readings when the MC is 7% or below.
Considering the challenges and frustrations we experienced while using the cabled push pin accessory, as well as the limited range for measuring MC in wood, this meter, and its push pin probe are not recommended for purchase.
- Built-in calibration check.
- Auto temperature adjustment with included temperature probe.
- Built-in species adjustment by selecting from different wood groups.
- Only measures wood MC down to 7%.
- Getting the push pins to penetrate the wood sample is challenging.
- Surface moisture significantly affects readings.
- Cable push pin probe failed to provide consistent, repeatable readings.
Extech MO220 Wood Moisture Detector
The Extech MO220 is a pin-style, conductivity moisture meter specifically designed for use in the wood industry
Objective Evaluation – Overall Score 3.7 out of 5.0
Accuracy – 4.1 out of 5.0
This meter’s cabled push pin probe showed mixed results when tested for accuracy. Although readings in the mid MC range were fairly accurate when compared to ASTM D-4442 oven dry standards, this meter did not perform as well at high and low MC ranges. In fact, this meter was unable to read samples with a MC below 7%.
Learn about our accuracy test procedures
Surface Moisture – 1.0 out of 5.0
After applying slight surface moisture to wood, the MO220 cabled push pin probe showed extremely inflated readings. These surface moisture results indicate that operating this meter in high humidity environments where condensation may form on the surface could lead to questionable readings.
Learn about our surface moisture test procedures
Meter Temperature – 5.0 out of 5.0
Meter temperature had a small effect on this meter’s cabled push pin probe reading.
A low meter temperature of 34.8° F increased the reading less than 1% in the presence of low MC compared to the room temperature reading of 70.5° F. In the presence of high MC, the reading also changed less than 1%.
A high meter temperature of 110° F in the presence of low MC changed the reading 0.4% while the reading taken in the presence of high MC decreased by 1.6%.
Learn about our meter temperature test procedures
Wood Temperature – 4.7 out of 5.0
Wood temperature had little effect on the readings taken with this meter’s cabled push pin probe, especially when the MC of the wood was low.
A low wood temperature of 33.6° F had almost no effect on the reading in the presence of low MC compared to the room temperature reading of 71.5° F. In the presence of high MC, the reading decreased by 2%.
High wood temperatures had very little effect on the reading in the presence of low MC compared to the room temperature. In the presence of high MC, it decreased by 1.8%.
Learn about our wood temperature test procedures
Reading Repeatability – 2.0 out of 5.0
The cabled push pin probe accessory failed to provide consistent, repeatable readings.
Learn about our repeatability testing procedures
Drift – 4.0 out of 5.0
Readings drifted slightly by 0.2%.
Cable Interference – 1.0 out of 5.0
This meter’s reading using the cabled push pin probe showed a decrease in accuracy due to cable interference.
Learn about our cable interference and drift testing procedures
Subjective Evaluation – Overall Score 3.5 out of 5.0
Learn about our subjective testing procedures
Ease of Use – 2.8 out of 5.0
This meter is simple enough to operate, but we found it challenging to get the cabled push pin probe to penetrate wood samples to the required depth. Battery installation is also not very convenient, requiring the use of a screwdriver. Documentation in the manual could be more comprehensive.
Quality – 5.0 out of 5.0
This meter has a solid, durable feel, and appears unlikely to break or malfunction with normal use.
Comfort – 4.5 out of 5.0
This meter itself is lightweight, compact, and fits easily in a shirt or jacket pocket. Its ergonomic design and rubberized grips along the sides make it comfortable to hold. However, the accessory probe felt uncomfortable in the hand.
Versatility – 2.0 out of 5.0
This is a single-mode meter (pin), which is typical. It is intended primarily for wood and includes eight different scales to choose from, depending on the species of wood.
Range – 3.7 out of 5.0
The manual indicates the range is 6% to 44% MC. However, we found it is not capable of obtaining readings below 7%.
Features – 2.8 out of 5.0
Readings precise to the nearest 0.1%. Low battery indicator. Built-in calibration check. Features automatic temperature compensation when used with the temperature probe. Lacks a HOLD function for use in tight spaces. Unlike Extech’s pinless counterpart, the MO280, this meter does not offer an audible or visual alarm for when the MC is outside the acceptable range.
Customer Service – 4.0 out of 5.0
Customer service appears knowledgeable and is able to answer all the basic questions, including the cost of repairs, turnaround time on repairs, etc. Prompt response provided to telephone calls, but the response time to our email inquiry was over 48 hours. The meter comes with a 1-year warranty. There is a flat rate for repair, the repair warranty is only 60 days.
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.