Best Moisture Meters for Firewood

For most households checking split firewood, the FLIR MR55 is our pick for its timber-group lookup, replaceable pins and automatic ambient-temperature compensation. Choose General Tools MMD4E for simple screening, or Delmhorst JX-20 when you need to enter wood temperature and select an external electrode. Test a newly split face, and compare a suitably corrected wood-moisture reading with EPA's below 20% moisture content guidance.

Quick picks

These are recommendations from manufacturer documents, with the scale limitations included in the choice.

Compare specifications and all conditions

FLIR MR55

Choose it for

Our main firewood pick

Wood display and limits

7–29% MC: ±2% MC; 30–99%: reference only; species fiber-saturation limit also applies

Temperature handling

Automatic, using ambient temperature

All specifications

Pins and package to compare

Replaceable 10 mm electrodes; standalone meter

General Tools MMD4E

Choose it for

Simple screening

Wood display and limits

Product page: 5–50% WME; manual: wood percentages; species calibration unresolved

Temperature handling

No user temperature correction documented in the linked manual

All specifications

Pins and package to compare

Product page: 8 mm pins, replacement pins, cap and battery

Delmhorst JX-20

Choose it for

Manual corrections and electrode options

Wood display and limits

6–60% MC nominal for Douglas Fir at 70°F; other species need their correction

Temperature handling

User-entered material temperature

All specifications

Pins and package to compare

Integral pins; JX-20W/CS includes case; JX-20/P01 adds a hammer electrode

Full comparison table ↔

Swipe to compare. Row labels stay visible.

Meter	Choose it for	Wood display and limits	Temperature handling	Pins and package to compare
FLIR MR55	Our main firewood pick	7–29% MC: ±2% MC; 30–99%: reference only; species fiber-saturation limit also applies	Automatic, using ambient temperature	Replaceable 10 mm electrodes; standalone meter
General Tools MMD4E	Simple screening	Product page: 5–50% WME; manual: wood percentages; species calibration unresolved	No user temperature correction documented in the linked manual	Product page: 8 mm pins, replacement pins, cap and battery
Delmhorst JX-20	Manual corrections and electrode options	6–60% MC nominal for Douglas Fir at 70°F; other species need their correction	User-entered material temperature	Integral pins; JX-20W/CS includes case; JX-20/P01 adds a hammer electrode

Meter	Choose it for	Wood display and limits	Temperature handling	Pins and package to compare
FLIR MR55	Our main firewood pick	7–29% MC: ±2% MC; 30–99%: reference only; species fiber-saturation limit also applies	Automatic, using ambient temperature	Replaceable 10 mm electrodes; standalone meter
General Tools MMD4E	Simple screening	Product page: 5–50% WME; manual: wood percentages; species calibration unresolved	No user temperature correction documented in the linked manual	Product page: 8 mm pins, replacement pins, cap and battery
Delmhorst JX-20	Manual corrections and electrode options	6–60% MC nominal for Douglas Fir at 70°F; other species need their correction	User-entered material temperature	Integral pins; JX-20W/CS includes case; JX-20/P01 adds a hammer electrode

Best for most firewood buyers: FLIR MR55

The MR55 manual provides timber groups and species tables, so there is a documented route from the log's identity to a setting. Groups 1–8 cover timbers; Group 9 covers plywood, drywall and OSB. Look up the actual species rather than using a generic building-material setting.

The important limitation is temperature: the meter corrects from ambient air, not a probe measuring the log's interior. Our recommendation is to avoid making a threshold decision on wood just carried between very different temperatures. Its quoted wood accuracy also stops at the species' fiber-saturation limit; a high reference reading is a reason to keep drying, not a precise water-content measurement.

Replaceable pins, a backlight and a worklight make this our practical middle choice. Bluetooth is optional: the current manual describes holding a reading and transmitting it to METERLiNK, rather than unattended logging. The older linked datasheet names FLIR Tools Mobile; these documents disagree on app naming.

See the MR55 and manufacturer specifications.

Best simple screening option: General Tools MMD4E

The MMD4E product page lists wood/building-material selection, reading hold, a cap calibration checker and replacement pins. It is our choice for someone who wants simple comparative checks and accepts the calibration qualification below.

General calls its wood range WME, while its currently linked MMD4E/MMD4E-B manual presents wood percentages without a species-correction table. We could not establish a species-specific conversion from these documents. Confirm that with General before treating a close reading as proof the wood meets a burning threshold.

Read the number, not just the colour: the current manual's wood high indication starts at 16%, which is different from EPA's firewood boundary. It also requires pin insertion of at least one-quarter of sample thickness for an average moisture reading. Short pins on a thick split cannot automatically satisfy that condition.

Variant trap: the current manual covers MMD4E and MMD4E-B. Its indicator blocks differ from the older MMD4E manual's separate coloured LEDs, and replacement-pin naming differs too: the current product page says PIN3, while the older manual says PIN3DE. Match replacement parts and instructions to the supplied meter; do not assume a suffix or a pin pack identifies a complete kit.

See the MMD4E package and current instructions.

Best for manual wood-temperature correction: Delmhorst JX-20

The currently listed JX-20 is our corrected-reading option. This recommendation covers JX-20, not a J-2000 listing: use the matching manual and parts. Its owner's manual supplied by Delmhorst Europe describes species, material-temperature and insulated/non-insulated pin corrections.

The reason to step up is control over those settings and external electrodes. Select NON-INS for integral pins and INS for an insulated electrode. The manual specifies a 26-ES hammer electrode for thicker wood and hardwoods over 4/4; it also specifies integral-pin use on wood up to 1½–2 in thick. Budget the electrode into your package decision if that describes your wood. Delmhorst's correction page treats values above 30% MC as qualitative; the nominal display range is not an accuracy guarantee throughout.

The regional package listing distinguishes JX-20W/CS, with a carrying case, from JX-20/P01, with the meter, case, 26-ES and ten contact pins. The SC version has different species/settings; JX-30 adds app features. Neither is the standard JX-20 covered here.

There is a documentation conflict: that listing says 72 species corrections; its linked November 2023 manual says 74. Confirm your species in the supplied meter instead of buying on the count alone. This is our specialist option, not the default purchase for a household stack.

How we choose

We compared official product pages, manuals, replacement-pin guidance and package contents. We have no published measurements of these meters; accuracy figures are the makers' claims. We weighted usable wood scales, species correction, temperature handling and serviceable pins above extra display functions. The EPA flyer supplies the split-face and burning context; EPA labels Burn Wise a historic programme and stopped updating it in October 2025. See our selection method.

Buying guide: compare the right moisture numbers

Wood MC, WME and relative readings are not interchangeable labels. A supported wood-MC measurement has calibration conditions, species assumptions and an accuracy range. FLIR's wood table and Delmhorst's correction instructions identify these limits; a percent sign alone does not.

WME means wood moisture equivalent. Protimeter explains that wood is the reference scale when its pin meters assess other building materials. WME is not inherently a meaningless reading on wood, but the label alone does not establish the correct calibration for an unknown species. For General, retain that uncertainty until the maker confirms it.

A relative scale compares wetter and drier locations. It does not automatically give an actual moisture percentage. Do not transfer EPA's firewood threshold onto a relative building-material reading, or onto a different material mode.

• Yes: Match the wood species to the maker's supported setting or correction
• Yes: Check the wood accuracy range and temperature assumptions
• Partly: WME: confirm what the calibration means for this wood
• No: Relative building-material readings cannot clear firewood against a wood-MC threshold

Cold logs: complete this settings worksheet

Delmhorst's correction guidance explains that colder wood reads lower on resistance meters. It says no temperature correction is needed between 50°F/10°C and 90°F/32°C for its calibration. Do not apply Delmhorst's correction tables to General or FLIR readings: they are not universal conversion tables.

The JX-20 listing gives a 0–255°F / −18–124°C temperature-correction range. Its regional manual confusingly labels that range “operating” and then separately gives 0–40°C as the operating range. Treat the wider number as correction capability, following the listing; use the narrower instrument limit and resolve any uncertainty with Delmhorst.

Our winter rule is simple: if wood temperature is unknown, the instrument is outside its operating limits, or the log is frozen, postpone the burn decision. Bring the setup into supported conditions and retest; an air-temperature display is not an interior-log thermometer.

Check the meter before checking the stack

Use the maker's electrical check before a sampling session and restore your wood settings afterwards.

A passing electrical check does not identify the species, establish log temperature or certify a stack. If checks keep failing, follow the maker's service instructions before relying on a reading.

Test a freshly split face

EPA illustrates splitting the wood, testing the newly split side and inserting the probes into the grain, with the meter's instructions providing the specifics. Choose several pieces from different parts of your stack, including pieces you suspect will be wetter; this is our suggested homeowner sampling routine.

Avoid standing water on the face, as General's current manual directs. Follow the chosen meter's pin-orientation and depth instructions. FLIR calls for insertion perpendicular to the wood's fibre structure; Delmhorst directs the pins parallel to the grain. Consult the matching manual rather than borrowing another brand's procedure. General's older manual warns against forcing pins into hard surfaces, and FLIR says not to strike its meter to drive them farther.

1. 1

   Prepare

   Check the instrument, species, scale, temperature basis and pins.

2. 2

   Split

   Expose a fresh interior face following EPA's illustration.

3. 3

   Measure

   Follow your meter's insertion instructions and take readings at several locations.

4. 4

   Record and decide

   Keep readings with their settings; flag wet or uncertain pieces for drying and retesting.

Keep a log, then decide what needs more drying

Use this suggested record each time; leave an unknown field marked unknown instead of guessing. Keep species separate. The JX-20 manual says changing species requires erasing saved readings, so copy a species batch before switching.

Keep drying pieces with supported interior MC readings at or above EPA's boundary. Also hold back pieces whose reading is close to it, whose species/temperature is unresolved, or whose display is reference-only. Our conservative recommendation is to resolve those uncertainties and retest, rather than letting a dry reading cancel out a wetter piece in an average.

Consider the sampled piece ready only when supported, appropriately corrected interior readings are below the guidance. Sampling pieces does not certify the entire delivery. Retain the record so the next check uses comparable settings.

Buying for a house survey too? Use our general moisture-meter guide and thermal-camera buying guide to compare those purchases separately.

Verdict

Choose FLIR MR55 for our best balance of documented timber settings and practical features. Choose General MMD4E for straightforward screening with its calibration qualification, or Delmhorst JX-20 for explicit material-temperature and electrode control. The useful result is a recorded interior reading with known settings; when that evidence is uncertain, keep drying and retest.