I was told by someone that their piano tuner recommends placing a cup of water inside their upright piano (on the floor not inside the mechanism!) for some purpose to do with humidity.

Is this a common trick and sensible advice? What exactly is the idea?

  • A little specific information - it's a fairly old wooden-framed piano, we believe approaching 100 years old. Possibly originally from New York but nobody is sure - it's a Wilbur but has a local English company name also, does that mean they maybe shipped it into the UK?
    – Mr. Boy
    Jan 15 '15 at 9:32
  • When possible, it's better to control the humidity in the entire room, rather than attempting to maintain local humidity inside the piano (which is, after all, not in the least made of any kind of humidity-barrier :-) ). Jan 15 '15 at 15:25
  • My parents received the same advice from their piano tuner, probably 30 years ago now. It may slightly raise the humidity inside the piano -- although whether by a significant margin, I don't know.
    – slim
    Jan 15 '15 at 16:59

That might depend on where the piano was made [& how carefully], its intended market locale & whether it has subsequently been moved from that location.

A good piano maker will season the wood it is to be made from in the country of the intended final destination so the entire seasoning is done in similar climatic conditions to those in which the finished instrument will eventually live.

Once seasoned, the wood is vac-wrapped & shipped to the factory, where the entire production line is then set to match those climatic conditions.

The piano is built in those conditions, vac-wrapped again & shipped back to where the wood was seasoned, for sale.

Under those circumstances, the only conditions I would even dream of messing with the humidity would be if the piano was being kept in a hot, dry environment - like a centrally-heated house - in a predominantly cold, damp climate; thereby unbalancing the makers initial consideration.

  • See my comment, just added - this piano surely pre-dates vacuum wrapping. I haven't met the tuner in person to ask if it's one of his "standard tips" or specific to this piano for somereason.
    – Mr. Boy
    Jan 15 '15 at 9:33
  • 2
    I think they used to use wax, in the old days, but I don't know for sure. The above information is straight from the horse's mouth, though - I used to work for Yamaha & have seen the production line & examples of the entire process… & what can go wrong if you don't do that ;)
    – Tetsujin
    Jan 15 '15 at 9:34
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    There are in fact special humidity devices to be placed inside pianos; I recall the piano at my parents' has a tube-like object placed in it, which is humidified in a bathtub every now and then.
    – Sanchises
    Jan 15 '15 at 11:42
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    which in no way goes against what I said. If you bought a piano in Louisiana then moved to Nevada it would be a good idea.
    – Tetsujin
    Jan 15 '15 at 11:47

I'm guessing it lives somewhere in England now, in a centrally heated house. Not too close to a rad or South facing window,I hope! If the frame is indeed wooden as opposed to iron, it will benefit from having a cup of water (or something with a larger surface area) in the bottom, as it will help to stop the wood drying out. This starts the pins on their way to slipping, due to the wood shrinking. Check the water level every couple of weeks.

Various products are available which control the temperature and humidity, connected to the mains, but are for more extreme situations than the weather vagaries in England.


In the flat with the central heating, humidity may get very low if its cold outside. This is probably an attempt to prevent the wood of the instrument from over-drying.

More safer and reliable seems to control the humidity inside the room. I would buy a simple cheap humidity indicator and some air humidifier. In comparison to the assumed price of acoustic piano, they are not expensive.

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