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I recently purchased a rebuilt Steinway A. It was delivered mid-November to my home which has it's own central humidifier. Great, right? Well, as winter wore on, I became curious about the humidity levels in the house and bought a hygrometer. To my horror, the humidity level shows 22%. A tech is coming out today to get the system running again. Does the rapidity with which the humidity level rises matter? Should I make some attempt to regulate how quickly the level rises? Thanks for sharing your expertise.

The wood will absorb moisture faster than it will dry but I don't think it will hurt the piano even so. 42% is all you are coming up to and the rate of absorbtion will slow as it approches. The humidity of the wood is what is critical. 7% is where it is for most of the US. If it has dried to 5% and isn't showing any soundboard cracks, they did a good job and it still has some compression crown.

kpiano

Wow! You know your stuff! How does one measure the humidity of the wood??? I don't think there are any cracks.

I think you are confusing Relative Humidity (something the applies to air) and Percent Moisture Content (something that applies to wood). The two numbers are not comparable. 5% Moisture Content wood does not have anything to do with 5% Relative Humidity air.

Robert Scott
Ypsilanti, Michigan

Raising the ambient humidity to 40% in a few hours won't hurt the piano - it actually takes a few days of higher humidity for the soundboard to absorb it. That's why a piano has to settle in to a new environment for a few days before it is tuned.

The tuning might change a bit as the humidity comes up. The middle notes of the piano will go a bit sharper. If the piano was tuned in November upon delivery, the ambient humidity was probably close to about 40% then, because it was a warmer fall this year. So the tune on the piano might be a bit closer with the increase in humidity.

Steinway's take humidity swings really well. They seem to fight to hold a tune till the humidity really changes, then the tuning gives out.

Thanks so much for the advice. Our technician came out to repair our system and seems to feel that we need to replace it with a $2,100. steam system. Ugh. We are going to repair the present system anyway just to see what the change in the hygrometer reading will be. Is there some guideline as to how long a piano can take inadequate humidity levels before damage is done?
For instance, if the repair only brings levels up to 30%? Thanks again.

Slightly low humidity in itself is unlikely to cause damage. On the other hand very high humidity, in itself, will cause damage by increasing the moisture content of the wood which reduces its stiffness (and resistance to compression) and, at the same time, causes the wood to swell. The swelling under conditions of very high humidity causes the damage (to the wood, but also rust on the srings). The wood damage later becomes visible when the piano undergoes conditions of very low relative humidity, loses moisture content, and wood parts shrink in size.

I have seen a new, well-constructed piano start to come apart (for example the veneer starts to come off) after a few years in an uncontrolled midwestern climate in which the summer relative humidity is above 80% and the winter below 10%. These are extreme conditions and not to be tolerated for a piano.

On the other hand, if you can keep the room in which the piano sits between 30% and 50% relative humidity, you can do well. You will need to install a Dampp-Chaser system in the piano to compensate for the relatively small changes in relative humidity; this will protect the materials, wood and metal in the instrument, and help keep it in tune for as long as possible.

Thanks so much, Mike, for sharing your knowledge. I assume from your post that their is no immediate danger so I have time to determine our best course of action. My nose tells me to install the steam system, but I don't relish paying for it! We do have air conditioning in the summer, the swing in humidity levels shouldn't be as drastic as in your example, so you have relieved my anxiety.

A steam/radiator type heating system creates a drier environment than any other type of heat, except a wood stove. It's a misconception, that because "steam" is piped though the house, the "steam" somehow adds humidity to the air. This isn't correct. The steam is in a closed series of pipes, and never mixes with the air in the house, therefore it adds zero humidity to the home.

If you have a choice for heat, please go with a forced air system with a furnace humidifier. In addition consider a damp chaser on the piano.

Actually, Bob, we do have forced air heat with a furnace humidifier. The humidifier is not functioning, but even with repair the tech suggested that it will never get the house up to 40%. He is suggesting a steam humidifier system.

pstudent,
i think i may have finally found a solution that works for me, a room warm mist humidifier with a digital hygrometer built in that turns the humidifier on and off at a certain humidity setting that you choose.

it's made by honeywell and sells at home depot for $39. it quickly brings the humidity up to the level you choose, then shuts itself off, then turns itself back on when the humidity drops below that level. so far, i am really happy with it. i use a digital hygrometer that is next to the piano to establish the set point for the humidifier. the humidifier is about six feet away from the piano. it's in a 12 x 19 ft. room.

might be just the ticket until you get your whole-house system figured out.

PStudent - when you said "$2100 steam system" I assumeod you meant Steam heating system. My error. I have an April Air furnace humidifier and forced air heat. It easily keeps the humidity 40%. The cost of an April Air is much less than the steam system you were quoted.

Thanks for the info, Pique. That may be worth a try. The room is not large, but it has two archway openings and no door. My wonderful moist air may waft away! Bob, if our system is not up to snuff, I will look into the April Air furnace humidifier, thanks for the tip!

pstudent,
my piano room has four doors opening into it, and at least two of them are open most of the time. the honeywell on the high setting produces a lot of humidity in a hurry.

i also looked into a whole-house system, but our forced air heat ducts are in an unheated and inaccessable crawlspace under the house (stupid, i know) and it gets so cold here that the condensation would be a serious problem, so not an option in this house.

after having been through four or five humidifiers in the past few years, none of which lasted or worked very well, i am thrilled to have found the honeywell, and so cheaply! it was a consumer reports "best buy" and also got really good reviews from consumers on various buyers' websites i checked out. some people reported having used it for four or five years with no problems.

PS,
Steve here... This is the unit I had installed inmy home (forced air) it seems to work well. The model 700 has an outside sensor, to compensate for outside temp changes...
http://www.aprilaire.com/product.as...egoryID=F16F78145781484A8A7C756B87F43AB3