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Temperature and Humidity

To keep a solid wood acoustic guitar in prime, playable condition, it's surrounding temperature and humidity must be controlled. These two forces are quite powerful, and, an instrument that isn't properly stored will succumb to damage. So, a climate controlled environment is essential.

If you grew-up in a cold weather climate, particularly one that is dry, you likely suffered from cracking lips during the winter months. You probably didn't like the feeling, but just accepted it as beyond your control. Working with wood, particularly sensitive instruments, clearly demonstrates that necessary precautions are paramount to stabilization. Just like your skin, if you take care of it, an acoustic guitar will play better and need less corrective maintenance. Therefore, the very same conditions we as humans feel most comfortable are the exact same conditions that are best for wood instruments, most particularly, solid and hollow body.  To do this for the best results, you'll find that trying to constantly control the environment in all situations will be very difficult. Instead, purchase a digital hygrometer and by checking it periodically, you will become sensitive to the right conditions that are best for your acoustic. However, just having a hygrometer isn't enough, you also need to know how to use it.

The amount of relative humidity in the air, or the RH level, can be measured by a hygrometer. The RH level, is therefore the amount of moisture which can be held in the air prior to its reaching a point of saturation. When the air temperature rises, it can hold more moisture. During the winter months, people heat their homes, offices, workplaces, and studios to stay comfortable. Doing this causes three things to happen:

1) The RH level, or, amount of moisture in the air drops as the air temperature rises.

2) As cold air is heated, the amount of moisture decreases, and, this means as the interior air warms up to 75 degrees or more, the RH level will drop significantly. This means that the necessary amount of moisture needed for your skin and instrument isn't sufficient.

3) Heating a home, office, work space, or studio, by its very mechanics, dries the air inside. The result is less moisture in the air, which means your acoustic guitar can warp over time, especially as the winter months gone on and the heat is used daily.

Dealing with Low Air Moisture Levels

In general, homes have an average range of humidity of between 30 percent and 50 percent. The human body enjoys about this same range, and, your acoustic guitar also benefits from between 45 percent to 50 percent. Room humidifiers are inexpensive appliances and make a great way to balance the RH level, which will also feel more comfortable to you.

Should you not have a humidifier, do not want to purchase one, or, travel a lot with your guitar, you'll have to regulate the RH level of your carry case. There are cases which do help to protect your instrument from any sudden temperature and moisture changes, as well as provide protection from physical damage. The case is generally the best place to store your acoustic guitar, even when at home.

You can monitor the RH level of your case by placing a hygrometer inside the case, near the body of your instrument, but do not place it inside the accessory case. Put a small humidifier inside the accessory compartment. This separation will provide an accurate measurement of the amount of moisture your guitar is exposed to inside the case. Do not place a humidifier inside the sound hole in the body of your acoustic because this can easily damage it through outright leakage or just too much moisture. Instead, use a reliable humidifier, two if necessary, and place these inside the accessory compartment to provide separation. Put the hygrometer near the heel of the neck of your instrument to get the best reading. Should the RH level remain low, place the humidifier next to the headstock, but secure it in place to prevent shifting and to prevent leakage.

For instrument owners that live in a hot and dry climate, like the southwest, use a swamp cooler rather than an air conditioner to increase moisture levels in the air of your home, which will not only benefit your instrument, but feel good to you.

Warnings about Low Humidity Levels

When the RH level in the air falls below 40 percent, the wood and lacquer might begin to crack over time. In addition, the top will also start to drop, and the action will be lower. The lower the action, the more the strings will begin to buzz, like when frets are out of place. If it's exposed to dry conditions long enough, it will cause the lacquer to check, and the glue in the seams will begin to lose its adhesive qualities. What's more, dry conditions can cause the fretboard to shrink, allowing the ends of the frets to protrude past the edge of the binding.

Such problems will make your guitar uncomfortable to play and can lead to permanent damage. One of the first signs of this is a noticeable drop in the lower and top action. You might also see hairline cracks along the bridge pin holes. These early warning signs allow you to take action to restore moisture levels before more serious damage occurs.


Warnings about High Humidity Levels

Though more humidity is generally not of as much concern, because wood can absorb moisture, it nonetheless is more difficult to correct. Should your guitar be in a high humidity environment, then simply turn on your home air conditioner, or, lower its temperature. The result will be a drop in the RH level in your home, which will in turn, cause it to be better environment for your guitar. If you live in a high humidity climate, do not cool your home with a swamp cooler as this will only increase the moisture level in the air, exposing your guitar to many problems.

When the humidity reaches 65 percent or more, the top of your instrument will rise, increasing the action, which can make it difficult to play or unplayable. It can also damage the lacquer, and the braces can begin to form an impression on the top. The points where the top is glued to the internal structure, which include the tail blocks, head blocks, bridges, and braces, can also be affected. This can cause difficulty in playing, as well as, permanent damage.

Avoid Sudden Humidity and Temperature Changes

Rapid changes to the temperature and moisture levels can be very damaging to your instrument. For instance, going from a climate where the humidity level is saturated, well above 70 percent, to a dry environment, where the RH level is below 40 percent, can severely inflict damage. This is why professional musicians traveling from state to state and country to country take preventative measures to protect their gear. The strings are loosened when before air travel and placed in heavy cases. Likewise, your guitar will be best protected by its case, so, keep it there as much as possible.


In the first three to five years, acoustic guitars are most sensitive to humidity levels. During this period, it is imperative that it remain stabilized, which will prevent future problems. The majority of vintage instruments are less susceptible to changes in moisture levels than a new guitar.

This is precisely why we go to such great lengths and only build guitars with dry tone woods. Using a specialized machine, known as a dehumidification kiln, we prepare our tonewoods. Over a period of two to three weeks, our woods are treated with the dehumidification kiln, through incremental and small temperature increases under a 40 percent RH level. During the time our tone wood is in the machine, it can shrink by as much as 3/8", or, even more. This clearly demonstrates how much of an impact moisture has on wood. As the bound moisture decreases, the tone wood becomes stabilized, and, this applies a level of protection for RH changes when the instrument is completely assembled. This doesn't mean that your guitar won't be affected by moisture changes, and, you should always exercise caution.

Moisture Restoration

If a guitar does become dried out, more humidity is needed to restore the instrument and prevent further damage. To reintroduce moisture to the wood, you'll have to place a humidifier inside the body and seal off the sound hole. This must be done with a lot of caution because it too can cause damage. You'll have to ring out excess moisture if necessary and place your instrument in its case for about three days, then, check it. You can also place a humidifier under the headstock, to provide the fretboard and bridge with more moisture. In addition, you can oil the fingerboard and bridge. It can take up to two weeks to bring the instrument back to good condition.

After restoring moisture to your guitar, you might find that not all the problems have been fixed. It may need professional attention, but these are generally inexpensive procedures. If you cannot restore your instrument's moisture and continue to have problems, you can contact us and we will provide you with instructions, or, we may need to make repairs.

Temperature Damage

Just like high levels of humidity can cause damage, so can high temperatures. Low temperatures, particularly when below freezing, can damage the lacquer. It is important to note that slow changes in temperature and humidity are less damaging than rapid changes. If you travel and the temperature differs from one location to another, allow your guitar time to acclimate. When an instrument is shipped or transported, especially during the winter, and, there is a significant change in temperature, it should be left in its case for at least 12 hours before it is opened. Why it might not be damaged right away if the case is opened, it could well sustain damage the next day because of the sudden change.