Humidity and Instruments

A lot of research has been done regarding this topic. Since it is at the core of what we do, we have some expertise on humidity's effect on stringed instruments.



What is the difference between absolute and relative humidity?

Absolute humidity is the total mass of water vapor present in a given volume or mass of air. It does not take temperature into consideration.

Relative humidity (RH) is a measure of how much water vapor is in the air. From a technical standpoint, relative humidity is defined as the ratio of the actual vapor pressure of water vapor to the saturation vapor pressure of water; in other words, how much how much water vapor is in the air and how much water vapor the air could potentially contain at a given temperature. It varies with the temperature of the air: colder air can hold less vapor and warmer air more. So changing the temperature can change the relative humidity, even when the absolute humidity remains constant.

Relative humidity is what we and the instruments "feel". When the RH is within the comfortable range of 40-60%, humans and instruments are happy. When the RH drops to lower levels, everything feels dried out and obviously as the RH climbs it can make an already hot day miserable.

Our hygrometers read RH and temperature, which are the two most important factors to consider when looking at moisture levels of the instrument's wood.

What is the average relative humidity around the world?

Does humidity stratify or naturally move within a closed environment?

Moist air rises, which is why hurricanes grow in size as they move over warmer portions of the ocean. Therefore, within a closed environment such as our humidors, the moist air will naturally rise. This is why we recommend placing the Boveda Two-Way Humidification packets in the packet holders in the lower corners of our single instrument humidors. For our ClimaCabs, we position the Acoustic Remedy Humidity Control System below the floor of the upper section and blow moist air into the cabinet.

What regions require the most humidification, dehumidification, or both?

In general, most regions in the United States will require some humidification. The winter months tend to be particularly dry inside of homes anywhere that uses a forced air furnace or wood stove to heat the interior. Many of these locations also experience relative humidity that is actually higher outside than it is inside during the winter months.

We recommend keeping the relative humidity between 45-55% inside the humidor . If you are experiencing levels above the upper end of this range, we would recommend implementing some dehumidification process. Most of the time this will occur in regions of the world with already elevated ambient humidity levels, such as the southeast United States or Asia Pacific. The top five wettest states, with the average relative humidity are: 1.) Alaska - 77.1%, 2.) Florida - 74.5%, 3.) Louisiana - 74%, 4.) Mississippi - 73.6%, and 5.) Hawaii - 73.3%. All of these locations would likely benefit from dehumidification only because they will not typically require heating in the winter months.

Measuring the internal relative humidity levels inside your home or building is important because each time the humidor is opened, you are introducing air into it and therefore effecting internal levels. We highly recommend monitoring these levels to understand what humidity control is required. Our line of Bluetooth monitoring devices are a simple and easy way to do this. In addition, a large number format hygrometer such as a ThermPro will assist with seeing the humidity levels from across the room.

Effects on Instruments

A lot of research has been done on the effects of improper RH on instruments. The luthiers have been preaching proper humidity control for years and in general, the average musician has learned to pay attention to this important topic. Listed below are some general conditions that can be experienced if the instrument is subjected to less than desireable humidity for extended periods of time. One interesting thing to understand is the large and rapid swings in humidity are the most dangerous because the instrument is swelling and contracting quickly. The main goal of any adequate humidity control regimen is to keeps things consistently in the 45-55% range. Instruments subjected to variances of approximately 5% downwards or upwards from this ideal range, for short periods of time, will not result in any catastrophic or lasting damage.

Dry Instrument Symptoms

  • Warped top (bowed or cupped)
  • Neck bow
  • Change in tone of instrument
  • Sharp fret ends
  • String action too low/notes buzzing
  • Cracking of the neck and/or body
  • Lifted bridge
  • Finish checks, cracks, or “orange peeling”

Wet Instrument Symptoms

  • Unusually swollen top

  • High string action
  • Unusual warp on the top, back or both at the end-block.

  • Improper neck angle. Sighting the neck to the bridge, the frets will appear to hit below the bridge

Instrument Types Effected

Although acoustic instruments tend to be the most prone to significant damage, electric solid body instruments are also affected. Acoustics, semi-hollow body, and hollow body electrics may need the most attention, but ulimately they all need proper care!

Submit Your Question About Humidity

If you have a question related to humidity, please contact us and we will be happy to answer to the best of our ability.
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