People often ask what they can do to look after their piano. I always tell them the most important thing is to keep the humidty level. The second most important is to keep the humidty level and the third...? You guessed it. Nothing is more important to the maintenance of a piano than controlling humidity. The picyure to the left is of a crack in the soundboard of a fairly recent vintage grand piano. There were no cracks in the soundboard when I tuned this piano in the pervious spring but when I returned in January there were five cracks, two of which that ran the whole length of the board. What could cause a soundboard to crack like that? Humidity, or in this case the lack there of. The picture below shows that the room that this piano was in was at 15% humidity! That is very unusual but it isn't uncommon for some homes to drop to the low 20's in the dead of winter and humidty in the low 20's can cause some real damage. It's so important that most tuners will carry a hygrometer with them among their tools to diagnose humidity related problems.
The fact is, there isn’t a piano made that will stay in tune if it is exposed to dramatic swings in humidity. The soundboard, bridges, back posts and pinblock of every piano are made of wood and those wood components swell with rising summer humidity and shrink with winter dryness. Unfortunately, because the strings are all different lengths, the pitch does not rise evenly. The reverse happens when the heat comes on in the fall and the inside air starts to dry out. The shrinking wood will allow the tension to come off the strings and the pitch drops accordingly.
Piano technicians know from experience, that pianos in concert halls, which are tuned throughout the year will always follow a predictable pattern. When the season starts in the early fall, the piano will be above pitch from the summer humidity. Throughout the fall the pitch of the piano will drop a little each time between tunings. This goes on until the spring when the humidity starts to rise. From that point on, each time they return they will find the piano has crept up in pitch and has to be brought back down to concert pitch. This continues until the fall and then the whole cycle starts over again.
Uncontrolled humidity swings can do more harm to a piano than just affecting the tuning. High summer humidity and extreme winter dryness can cause cracks in the soundboard and bridges. The cracks will appear in the winter when the wood shrinks but the high summer humidity may have been the cause, as the wood crushed together when it expanded only to separate when it dried out later. Extremes in humidity can also lead to sluggish or sticking action components. I always get the most calls to fix sticking keys in the dead of winter and during a summer heat wave.
The Piano Life Saver humidity control system works silently raising humidity in dry conditions and lowering humidity as humidty rises above ideal conditions. The system is installed inside upright pianos and under the soundboard of a grand piano. Call or text 905-945-9455 or email firstname.lastname@example.org for an installation price quote.