Humidity and Temperature - The effects on your piano
John E Nafie
The stability of the surrounding environment will have a great effect on the tuning stability of your new/used piano.
All pianos contain a vast amount of different kinds of wood such as case parts, pinblock wood, wooden keys, structural frame, soundboard, action parts, and more.
You cannot change the laws of physics and all this wood "will" react to the surrounding atmosphere in the room where the piano is located. Therefore, the more consistant you can keep the temperature and humidity around the piano the better your piano will perform and stay in tune.
As people, we tend to react to temperature more quickly than humidity. A room at a temperature of 65° feels cool, at 70° feels comfortable, and at 75° usually seems quite warm.
However, when it comes to humidity, we don't react until we feel extreme changes like 75% or higher as being really humid, or our skin feels tight and dry if the humidity is down in the 20% range.
Pianos react severely to such drastic changes. The most desired area for temperature is usually around 68 degrees with approx 42%-45% humidity.
Too much humidity causes keys and hammers to stick, strings and metal parts to rust, and the frame of the piano to swell causing the piano to go out of tune.
Too little humidity causes wood to shrink creating loose parts, split soundboards, and pinblock damage.
Exposure to extreme situations or fluxuations for any period of time can cause permanent damage.
Measuring Temperature and Humidity
A small Hygrometer/Thermometer (easily and inexpensively purchased) can be an invaluable tool to accurately let you know what is going on in the environment around your piano. Again because we are mostly interested in extreme readings either high or low from our target (65°, 42%-45% humidity) it is very helpful to obtain a unit that also has a history setting. This records the high/low temperature over time and also the high/low humidity over time. (Max/Min readings)
When you take it home and install a battery you begin fresh with all settings at the same numbers. However as time goes by - days, weeks, months, these number settings (Max/Min) may begin to separate by more than +/-10 degrees and or +/-10% humidity. If this is the case, it is a good idea to consult with your piano tuner about options for attempting to stabilize the room environment.
Special systems are manufactured by Dampp-Chaser Corp. to help when unstable conditions are proven to exist in the room.
When the room is too wet - heat is the solution and it is easier to heat the piano than to heat your entire room or house to counteract the moisture. Often times too much moisture shows up at unexpected times like the summer when heating systems may be turned off and doors and windows left open to the outside air. In the Pacific Northwest we have lot of water surrounding us and humidity readings in the summer can be high.
Grand piano system Vertical piano system
When the room is too dry - moisture must be added to the air around the piano. This can be accomplished is several ways. With a vertical piano a humidifying system can be installed in the bottom of the piano which will control the air inside the piano. On a grand piano the system is installed "under" the piano and is made more effective by the addition of a piano cover as well.
If the issue is severe, sometimes it is best to work with the entire room by adding a room humidifier. Some products I personally recommend come from Hunter corp (usually available at Sears), who manufacture room humidifiers that for around $100 can usually solve your problem.
Humidifying has special concerns because of the use of standing water, wicking pads, and problems like mold and mildew. Try to find a unit that has adaquate water storage so you are not constantly having to add water to the system and in the case of Hunter products the filter is only changed approx. once a year without having to add chemicals to the standing water to prevent the mold and mildew.
Hunter Humidifiers (click underlined link)