Humidity Control

Piano Tuning Phoenix by Wes Flinn RPT

Mythological Greek Phoenix

Humidity Control

— by Wes Flinn RPT

‘Humidity Control’

* “Humidity Control” in regard to pianos includes any of the various remedies or methods of controlling the surrounding humidity level (referred to as “RH”, or “Relative Humidity”) of the air where a piano is located.

Click here, or Scroll down to end of this entry for a list of available “evaporative” units — Note that small medicinal “mist” type units will not work

The reason for this extreme attention given to “humidity control” in dealing with pianos, is that an acoustic piano (see definition above) is constructed necessarily by design of wood or wood product derivatives, and is extremely vulnerable to severe humidity conditions. Very simply, it can break up, crack apart, deteriorate or become non-functional when the humidity levels in the air around it become too low or too high and outside of its design parameters. A piano is not alone is this predicament, as all wooden products suffer this limitation — it is well understood how solid wood furniture cracks and breaks apart in low humidity conditions, and how expensive musical instruments like violins or cellos or clarinets and even brass instruments need protection and humidification to prevent damage from adverse humidity conditions.

If you feel this attention to humidity control for pianos is exaggerated, even irresponsible, I humbly suggest that this attention is very well founded. The reality is that your piano, when located in adverse low humidity conditions, really will crack or break or self-destruct in some way. It is not a matter of “if”, but rather a matter of “when”. I have observed new pianos “explode”, and older pianos become useless, deteriorating into firewood because of storage or location in uncontrolled humidity situations, such as garages or storage units or vacation houses.

Almost every piano I visit in Arizona is suffering from some form of low humidity damage, in the form of pinblocks deteriorating to softness, soundboards showing stress cracks, tunings becoming very instable, pitch levels going crazy. Sometimes inner parts in the action are suddenly breaking, which requires immediate and expensive repair to avoid further damage. Often the damage is already fatally done, and the piano becomes useless without extensive repair — for examples, see Review #10 on this Website, describing a Kawai 7-foot home concert grand piano shipped to Arizona from Florida, which was both shipped and stored improperly before delivery: what should have been a simple tuning became a $3000 raising from the dead, because the pinblock was ruined, and most all glued parts of the action separated and had to be repaired, which in turn necessitated a Full Maintenance Service as well as totally re-tuning; and, also see Review #22 on this Website, describing the early and effective results of an area humidifier.

Low humidity conditions affect a piano most severely, suddenly

High humidity conditions affect a piano, not as severely or suddenly

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The simple and least expensive solution to control low humidity conditions is to install an area humidifier in the general location where a piano “lives”, and keep the RH level above 30% RH at all times. An automatic humidifier can be set at 35% RH, and the piano as well as all the people living with it become very “happy campers” !!

Also, adding an area humidifier to your home will greatly increase your personal comfort level, improve cooling and heating efficiency, reduce cooling and heating costs, PLUS bring all the benefits of steady humidity to a piano, etc. to a degree that you will really wonder why no one ever explained about all this before! Take this information seriously, and add one of the humidifiers described below.

The choice of area humidifiers for a piano protective purpose MUST be the “evaporative” type, and NOT the mist type used for medicinal purposes. The unit should also have a built-in and automatic device called a “humidistat” ( or a can be a “hygrometer” ), which is an “RH” or relative humidity meter that measures/regulates humidity in the air, and automatically turns the unit on and off to control an exact level of humidity. An evaporative humidifier unit without a built-in humidistat can also work just as well, but then you must also purchase a free-standing hygrometer to work with it in order to control an exact level of humidity — it is plainly much easier and less expensive to get a humidifier with the built-in automatic humidistat, and many such units are available on today’s market.

Pianos are known to be “safe” from low humidity atmospheric damage if the humidity level is kept above 30% RH in the air surrounding it. Pianos can usually tolerate high humidity conditions, even 70% RH or above, without structural damage, but pianos often begin failing progressively when located where humidity levels drop below 30% RH for any length of time. Setting an automatic humidifier at 35 to 40% RH virtually solves low humidity protection problems.

To control high humidity conditions, or conditions where the humidity or temperature conditions are variable all the time, the Dampp-Chaser system is the only solution – see below.

Please note: the Dampp-Chaser climate control system is the best, although the most expensive to purchase yet the least expensive to operate, long-term solution to control all types of weather temperature or humidity conditions that affect pianos — see information below. The total conditioning obtained by using a Dampp-Chaser system also protects and preserves tuning, thus tunings will last much longer using a total climate control system like the Dampp-Chaser.

To control low humidity conditions, an area humidifier does a completely acceptable job of protecting a piano. But it does not, and cannot, help preserve tuning duration and stability as does the Dampp-Chaser climate control system, because an area humidifier is only able to control the humidity factor of air surrounding the piano, and has no way to control the temperature factor involved in preserving both piano tuning and piano tonal qualities.

Another method of humidity control is to install a humidity control system into your household air-conditioning system. This method is the most expensive, but adds additional benefits at no extra cost of providing comfort and protection to all the people who live in the house with a piano, as well as to all the contents of the house, including furniture, cabinets, house structure, and to other valuable possessions you might own such as other musical instruments, antiques, historical books and libraries or similar treasures, etc. Please note, however, that household humidity systems are “protective” only, and only accomplish the same purpose as area humidifiers already mentioned above — they cannot accomplish the tuning and tonal benefits provided by a piano climate control system such as the Dampp-Chaser system described below and in the “Climate Control” section of this website (click tab at top of this page). If budget is no problem, the perfect solution is to install a household humidity control for all the reasons mentioned here, as well as the Dampp-Chaser system in the piano itself to develop both the ultimate care factor and ultimate performance capability for the piano.

Area Humidifier


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Please save yourself time, expense, and buyer’s remorse by using the following rules to obtain area humidifiers suitable to serve piano needs:

(1) Manufacturing models and options have become so diverse and changeable that standard, reliable area humidifiers are no longer available retail on a consistent basis – instead of making recommendations on this website about worthwhile models available, I now offer the service of recommending current units suitable for the purpose – send me your email request for current information at:

(2) For piano use (as well as general larger area use) remember to use only “evaporative” type humidifiers – the smaller single room humidifiers are designed for medical purposes and are usually the “mist” concept, instead of the “evaporative” concept – don’t buy a mist concept humidifier, as it will not service the purpose, and will be a total waste of money.

(3) Regarding ALL evaporative humidifiers, understand that the rule is ALWAYS to buy the largest unit where you have might have the floor space to locate it – the reasons for choosing large is that large units can always run the most quietly, and always require the fewest refills.

(4) If you are interested in “whole house” humidification, typically you can use two units in your house, which in combination with your normal air conditioning, will function much the same as central air humidification.

(5) The best of all systems is always a central air humidification system, if your air conditioning unit will support the application.


“Dampp-Chaser” is a Climate Control system for a physical, acoustic piano, either upright or grand style.

Pictures and details are located on this website at:

Climate Control system for piano

Cost starts at $475 installed for an upright piano, or for up to a 7-foot grand piano. For larger than 7-foot grand pianos, cost installed is $700.

“Dampp-Chaser” is the every day name of the biggest selling, best known product for the purpose of controlling humidity and temperature conditions inside an acoustic piano cabinet. A piano is constructed basically out of wood in the cabinet and soundboard, then steel (strings with copper wrapping) is used for the strings, and cast iron is used for the plate that holds anywhere from 20,000 pounds of tension in a small piano to 65,000 pounds of tension found in large grand pianos.

All of these materials used in constructing a piano are at odds with each other regarding expansion and contraction rates that occur when there temperature or humidity changes — which occur all the time every hour of every day of the year.

This phenomenon of stretching in contrary and opposite directions at different rates causes a piano to “go out of tune.” This can happen slowly or very quickly with a sudden or severe weather change. Using the Dampp-Chaser almost eliminates this kind of problem, and keeps the piano much more closely in tune, as well as protected from either the normal and slow or the fast and severe weather changes.

“Piano Life Saver System”

This is the actual trade name for this product, and it is manufactured by the Dampp-Chaser Corporation. The product has been in use since 1947, and has taken on the nick-name of “Dampp-Chaser” as it is commonly known to everyone today.

More information can be found both on this Website, by clicking the ‘Climate Control” tab above, then by clicking on the corporate links in that section. Click here for pictures.

Climate Control System” = systems like the Dampp-Chaser

Humidity Control” = information about pianos and humidity.

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