Moisture Meters for Firewood (The Ultimate Guide!)

Firewood moisture meters can be a valuable tool for anyone with a wood stove, fireplace, or masonry heater.

We always monitor the moisture content of our own firewood before burning it to make sure we are at the optimal moisture level. This complete guide will explain what they are, how they work and review the many firewood moisture meters out there so you can choose the one best for you!

Moisture Meter Comparison

What does a Moisture Meter do?

Moisture meters detect moisture levels in certain materials such as wood and masonry. Often they can be used to determine if there's a leak in a house. For example, let's say you are interested in buying a house, but discover a water stain in the attic near the chimney...but the sellers say that it was an old leak that has been fixed. With a moisture meter, you can test the wood to find out if the water leak is recent or not.

Or, similarly, you have some drywall that appears wet. With a moisture meter, you can figure out where it's the wettest to locate the leak.

For our purposes, a wood moisture meter measured the dryness of a piece of firewood to determine whether or not it is good to burn.

Why do I need a moisture meter?

A moisture measuring system is usually used for fuel combustion in open fires and stoves. Burning wet wood may also cause serious problems with wood stoves, fireplaces, masonry heaters and chimneys...and lungs!

Wet wood produces more smoke...which can cause respiratory issues. According to the EPA, smoke contains "particulate matter" that can contribute to asthma and bronchitis.

In a more spectacularly violent scenario, burning wet wood produces more creosote. Creosote can build up in your chimney to a point where it can ignite into a chimney fire. While your chimney is built to handle smoke, a fire inside can crack the lining and allow fire to transfer to the wood framing of your house.

By testing firewood with a moisture meter, you can be sure that the moisture content of your firewood is at a low enough level.

And, believe it or not...wood can be too dry to burn. Wood that is TOO dry also burns less efficiently. Wood burns by heat converting it to gas...it's that gas that actually burns. (Which is why flames look like a gas and not a solid!) When wood is too dry, it burns (converts to gas) so fast that the stove air intake can't provide enough oxygen to keep up...so the gasses go up the chimney and out into the atmosphere unburned...and unconverted to heat. (Just think of all that money spent on firewood going "up in smoke." Yikes!

Unless you're a gray-bearded old-timer that can tell the species of a tree by the sound it makes when you spit on it...you can't get reliable moisture reading without a meter!

And, not trying to be cynical here, but what some unscrupulous firewood dealers sell as "seasoned" wood....well...let's just say I wouldn't rely on it. When you tell them that you have a moisture meter and would like to check how seasoned it is before you shell out good cash for chunks of wood, you can be sure you'll get what you paid for!

How dry should my firewood be?

For the reasons mentioned above, well-seasoned firewood should have a moisture level between 15-20%.  Splitting wood can help it season faster!

How firewood moisture readers work

Moisture meters either use electromagnetic fields or electrical current to measure wood moisture.

Pin vs pinless moisture detectors

Most Moisture meters are either Pin-based or Pinless. Pin-based moisture meters monitor the resistance of wood when you push the pins into the wood.  A pin-based wood moisture tester sends a small electrical current from one pin, through the material being tested, then back to another pin. Since water is an excellent conductor of electricity (which is why you're not supposed to play with toasters in the bathtub), the meter is measuring moisture content based on wood resistance

Pinless moisture meters use pads to create electromagnetic waves in the wood. By measuring changes in the waves, the meter calculates moisture content.  They can usually measure moisture content down to 3/4" below the surface and don't leave holes in the wood from the pins.  (Which is why they're often called "non-destructive."

Temperature and Moisture Readings

Temperature does affect moisture readings.  Some moisture meters have built in temperature compensation but others do not.  If you choose a meter that doesn't factor in temperature, try to test wood at similar temperatures for consistent readings.

How do I use a firewood moisture meter?

Pin

First, turn the power on!

Then, many moisture meters have "modes" for different species of wood. Oak, for example, is much denser than pine, so to get more accurate readings, better quality moisture meters account for this.

So choose the mode best suited for that species of wood.

Next, cut or split the piece of wood in half. Since the pins only penetrate the wood a few sixteenths of an inch, and wood will dry from the outside in, you will only get accurate moisture content readings if you get away from the edges.

After you split the wood, stick the pins into the wood and look at the moisture reading on the digital readout. (Be careful with the pins...push firmly but carefully...and pull the meter straight back out of the wood so that you don't bend or break the pins!). If the wood is really hard (like hickory or black locust) use an awl or a small drill bit to pre-drill holes for the pins.

Since there can be variations in wood, for the most accurate readings, repeat the process 2-3 times to get an average.

(It kills me when I read reviews and some wack-job complains that "this meter sucks and doesn't give accurate readings. I got 3 different moisture levels!" Dude...it's wood...it's going to have variations...it's what wood does!)

Pinless

Like the pin-style moisture meter, turn it on first!

Next, if your moisture meter has different scales, select the wood type that you are testing.

Also, split the wood in half so that you get the most accurate reading from the inside of the wood and not the edge exposed to air. (Pinless moisture meters read a bit deeper...down to 3/4 of an inch, but still not really deep enough to get to the center of a piece of firewood).

Then read the percentage from the LCD display.

Features to look for

Measuring Range

A firewood moisture meter doesn't have to have a large measuring range. I mean...really...7 points would do: 14-21%. Anything higher needs to dry more...anything less should get hosed down. (Or burned in the fire pit!)

Some meters report from 2% up to 99%. However, measuring a moisture content between 6-40% would be more than adequate.

Accuracy

Consumer-level moisture meters' accuracy usually falls around 2%. And some models don't even provide accuracy numbers. But let's be real here, folks...we're not entering Narnia. Being plus or minus a few percentage points isn't going to burn down the house. Especially given the challenges for ascertaining a consistent moisture level anyway.

Doing rough math, I have about 1500 pieces of firewood in my woodshed...I'm not testing every single one. So while some sites who want to sell you high-end moisture meters tout the importance of precision accuracy, I recommend something reliable in a fair price range.

Built-in Modes

Although precision accuracy is overrated (IMHO) for a firewood moisture meter, reliably reporting the ballpark moisture level IS important. And built-in modes or scales do that.

Some moisture meters offer up to 8 modes. Others only 1. Since there's such a significant difference between the density in wood species, you want to at least start in the ballpark with the right moisture meter settings.

At a minimum, I would choose a firewood moisture meter with 4!

Calibration

Measurement instruments themselves are often inconsistent. If you don't believe me, use three different tape measures to find the width of your refrigerator. (Then post the results in the comments. I'm curious...but will bet a set of splitting wedges that they're not all within a sixteenth of an inch)

My lovely bride who works in a medical lab running machines worth more than our house that have to be calibrated. The hospitals buy "control" specimens with known values so she can test the machine

So a calibration feature on a moisture meter helps get an accurate moisture reading.

Backlit LCD Screens

For some strange reason, now that I'm in my 50's my arms have gotten shorter...I can't read small print because I can't hold the words far enough away from my face. Couldn't possibly be my eyes...

Anyhoo...having a large backlit LCD screen, though not critical, is a nice feature to have in my book!

Auto Power Off and Low Battery Alert

I don't care much about low battery functions alert. I don't foresee any emergency situation where I'll need to check wood moisture to save the world. I can wait until I find a new battery.

However, knowing that I have oodles of stuff flying around my head, I KNOW that forget to turn the darned thing off and blast through a battery each time I use it. And, in several reviews I read, purchasers complained that some models turn on when stuffed into a shirt pocket. So I'll take the auto power-off option!

What are the best moisture meters for firewood in 2021?

Best Pin Style

The Tavool wood moisture meter (MT270) is a great moisture meter that does an excellent job balancing useful features at a reasonable price.

With eight calibration scales for multiple species of wood and a built-in self-calibration, you can be sure to get an accurate reading for moisture levels.

This moisture meter works with moisture levels ranging from 6-60% with an accuracy of +/- 2%.

It has a large backlit LCD screen, auto power-off, and comes with 3 AAA batteries.

This moisture meter boasts a 4.5-star rating with over 2600 reviews. Reporters say they are "able to quickly get an accurate measurement" of moisture content and that that the moisture meter is "durable and sturdy."

One cool aspect of this digital wood moisture meter is its temperature compensation feature. By factoring in temperature, it reports more accurate firewood moisture.

Best Pinless Moisture Meter

The best moisture meter in the pinless category is the Dr. Meter MT-500. This pinless moisture meter (also called a "non-destructive" meter because it doesn't require you to poke holes in firewood or building materials to measure moisture content) also provided great value.

It boasts a total of 10 modes and one reviewer called it "very accurate for the price."

This moisture meter works with moisture levels ranging from 4-80% with an accuracy of +/- 2%.

It has a large backlit LCD screen, auto power-off, low battery warning and comes with 3 AAA batteries.

This moisture meter garners a 4.5-star rating from over 650 reviews. Reviewers report that it is a "Terrific little device. Easy to calibrate, and afterward, gave me consistent/repeatable measurements on a variety of different woods."

The 1-star reviews (only 6%) fell into 3 categories...the unit didn't work on arrival, it gave inconsistent measurements, and was "difficult to use."

Best Runner-Up Firewood Moisture Meter (Pin-Style)

I'm intrigued by the Giant Viking moisture meter. Its moisture level range is 6-60%, it offers 8 modes, and is fairly accurate (according to reviews).

It has a large, backlit LCD screen, auto-off, longer pins, and a protective cap.

It appears to be a relatively new product with only 66 reviews, but it averages 4.5 stars. Reviewers report that "The meter work(s) perfectly and could not be easier to use."

In a world of imported products with often poor customer service, this company makes it a priority. This firewood moisture meter offers a " 3-year-replacement-warranty. If it lets you down, we’ll replace it. No questions asked."

To support this, one reviewer reported that the moisture meter worked great, but called the company with questions, and "All questions were immediately answered by the company's representatives quickly and effectively."

Best Runner-Up Firewood Moisture Meter (Pinless)

The Wintact WT630 firewood moisture meter looks interesting. Like most of the other highly rated firewood moisture meters, it has 8 modes, auto shut-off, and a large backlit screen.

Unlike other meters, it has a wider measuring range (.5-70.5%), more accuracy (+/- 1.5%). In addition, it claims to measure moisture level to a depth of up to 2 inches! (Most only get down 3/4 of an inch.). Detecting moisture this far below the surface keeps you from having to split the wood so much to get accurate moisture readings.

Reviews give it 4.5 stars (over 650 reviews) and say that this is a "good meter that reads quickly and consistently."

One 2-star review reported that this firewood moisture meter struggled with accuracy when trying to get the sensor pad to sit right when he didn't have a flat test surface. This review also reported that the instructions were "so mangled and confusing that reading it aloud would make for a good comedy routine."

Final Thoughts

Firewood users should invest in a good wood moisture meter. Whether you want to make sure that the wood moisture of the firewood you are buying is what the seller claims or you want to make sure that you are burning firewood safely and efficiently, good moisture meters will help.

Use this guide to pick the best moisture meter that fits your budget and lifestyle.

Frequently Asked Questions

Q. What is a good moisture reading for firewood?

A. For burning efficiency, health safety, and chimney maintenance, firewood moisture content should fall between 15-20%.

Q.How do I test my firewood with a moisture meter?

A,If you have a pin-style firewood moisture meter, remove the protective cap from the pins, turn on the moisture meter, calibrate it (if it has that function), then insert the pins into the firewood. Press the "hold" button (if the moisture meter has that function) and read the moisture content from the meter screen.

Q. Can you burn 30% moisture wood?

A. You can...but you shouldn't. Putting wet wood in a wood-burning stove creates excess creosote which could lead to a chimney fire. Even burning firewood with high moisture content in a firepit releases unhealthy particles into the atmosphere. Instead, stack firewood that has high moisture content and let it dry. Use a firewood moisture meter to check the drying wood in a few months!