Temperature and Humidity Guidelines
for Pipe Organs


Tonal Finishing and Tuning

During the tonal finishing and tuning of the organ the temperature of the organ room should be maintained at the same level as normally set for Sunday services (ideally 68 degrees Fahrenheit or 20 degrees Celsius) for a minimum of 10 hours prior to the tuning. The tuning standard of an organ is usually 440 cycles per second at the above temperature.

General Guidelines

Ideally, an organ should be in a room with a constant humidity and temperature. However, no major problems should be anticipated if temperature and humidity are kept within the limits recommended below. The ambient temperature in the room should be brought back to the level normally set up for public service before the instrument is used, otherwise it will be out of tune. Usually, a ten hour period is long enough for all components of the organ to reach a good equilibrium of temperature. However, when the instrument has to be tuned, we recommend lengthening this period, especially if the temperature was maintained to the minimum indicated below.

Temperature range:

Sudden or extreme temperature changes must be avoided, otherwise permanent damage might be caused to the organ. Raising and lowering of the temperature should be done gradually at a maximum rate of plus or minus 2 degrees Fahrenheit per hour (plus or minus 1.5 degrees Celsius per hour). The basic reason for increasing and lowering the temperature of the ambient air very slowly is to make sure that the dew point will never be reached. Excess of humidity and excessive dryness can be dangerous to a pipe organ.

Rapid cooling of a room may raise the relative humidity to the dew point and cause condensation that would be harmful to the leather, the metal parts, and the very sensitive mechanism of the instrument. Rapid heating of a room may dry the chests and other large wooden parts too quickly around the edges and cause splitting.

No part of the organ should be subject to direct radiation of heat (strong lights or sun). Concentration of warm or cold air around the organ must be avoided. Temperature should be uniform throughout the room. Consequently, lighting, air duct intakes or outlets (heating or air-conditioning) should not be installed near an organ nor should they blow air toward it, for not only could it put the organ out of tune, but air ducts could create a concentration of polluted air that can cause rapid deterioration of some materials. An HVAC system may increase the air movement in the organ room and around it, causing instability in the speech and tuning of the pipes. It is important to note that air movement in and around the organ should not exceed 2' per second with or without such systems.

Recommended Humidity ...

It is recommended that the humidity of the organ room be kept between 50% and 60%. The maximum should never exceed 80% and the minimum level should never fall below 30%.

A humidifier or de-humidifier should be used when necessary. However, dew point must NEVER be reached. The humidifier should be located far enough from the organ so that moist air is not deposited directly on any organ parts but is spread throughout the room.

No major problems should be anticipated if temperature and humidity are kept within the recommended limits. The ambient temperature in the room should be brought back to approximately that level before the instrument is used in service, concert or practice, otherwise it will be out of tune. Usually a ten hour period is long enough to reach a good equilibrium of temperature. However, when the instrument is to be tuned we recommend lengthening this period, especially if the temperature is maintained at a very low level (temperatures below 45 degrees Fahrenheit are not recommended).


Back to the Dodington home page revised April 8, 2009