CRITICAL FLAW ALERT!
This meter exhibits a critical flaw—namely its inability to read below 8% moisture content. This flaw renders the meter essentially unusable for a number of common applications, including for flooring installations and furniture making. We deducted one star from our overall rating to reflect this critical flaw.
The Extech MO220 is a pin-style, conductivity moisture meter specifically designed for use in the wood industry. The MO220 offers several useful features, including built-in calibration check, species adjustment, and auto temperature adjustment.
It scored reasonably high in accuracy, especially in the mid-range from 9% to 18%. but cannot provide readings when moisture content (MC) is less than 8%.
We experienced bending and breaking of its pins, which would be a likely source of frustration for anyone using this meter.
Given its limitations, we do not recommend this meter for anyone who needs to measure wood with low MC.
- Built-in calibration check.
- Auto temperature adjustment with included temperature probe.
- Built-in species adjustment by selecting from different wood groups.
- Not capable of obtaining measurements below 8% MC.
- Pins easily bend or break.
- Easy to hit the wrong button and change the species setting.
- Surface moisture significantly affects readings.
Objective Evaluation – Overall Score 4.1 out of 5.0
Accuracy – 4.0 out of 5.0
This meter lacks the capability of taking readings below 8% MC. It provides good accuracy in the 9% to 18% MC range and slightly less accuracy in the upper range of MC.
Learn about our accuracy test procedures
Surface Moisture – 1.0 out of 5.0
After applying slight moisture to wood, the Extech MO220 showed extremely inflated readings. 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 – 4.6 out of 5.0
Meter temperature had some effect on this meter’s readings.
A low meter temperature of 34.8° F in the presence of low MC increased the reading 0.4% from the room temperature reading of 70.5° F. In the presence of high MC, the reading decreased only by 0.6%.
A high meter temperature of 110° F in the presence of high MC showed a 0.5% decrease in the reading from room temperature. In the presence of high MC, it dropped 2.2%.
Learn about our wood temperature test procedures
Wood Temperature – 4.0 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 decreased the reading less than 1% from the room temperature reading of 70.5° F. In the presence of high MC, the reading decreased by 2.1%.
A high wood temperature of 110° F in the presence of low MC decreased the reading 1.2% from the room temperature reading. In the presence of high MC, it dropped by 3%.
Reading Repeatability – 5.0 out of 5.0
Extech MO220 meter readings were highly repeatable.
Learn about our repeatability testing procedures
Drift – 5.0 out of 5.0
Readings taken with this meter did not drift after 3 seconds.
Cable Interference- N/A
The cable interference test is not applicable to this meter, except with the use of the push cable accessory. Please refer to the separate Extech MO220 push cable review.
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 – 2.5 out of 5.0
This meter is simple enough to operate, although when using the meter without the probe, it is easy to accidentally hit the species button, thus changing the species setting. If this isn’t noticed immediately, subsequent readings will not be correct. Battery installation is not very convenient, requiring the use of a screwdriver. Documentation in the manual could be more comprehensive.
Quality – 4.3 out of 5.0
This meter has a solid, durable feel, and in most respects, seems unlikely to break or malfunction with normal use. However, we experienced a significant problem with pins frequently bending and breaking. We recommend that the user of this meter plan ahead and have a supply of replacement pins handy.
Comfort – 4.5 out of 5.0
This meter 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.
Versatility – 2.0 out of 5.0
This is a single-mode meter (pin), which is typical. Readings must be awkwardly viewed upside down after pins are inserted into the wood. This meter 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 states that the range is 6% to 44%, but in practice, we found this meter is not capable of taking readings below 8% MC.
Features – 2.8 out of 5.0
Readings precise to 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 the Extech 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. 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.