First of all, thank you for your comments on my previous threads regarding selecting a piano for my daughter. After all these years she is on her Casio keyboard no longer! She is now the proud owner of a pristine 2002 Charles Walter 1520 in a lovely Queen Anne cherry. (Incidental life lesson as well...After playing the CW and comparing it to all the others she tried she remarked, "I just want to make sure I am really judging it on its merits and not being influenced by outside factors like ...its so cute!" I told her to keep that in mind when it comes to choosing a husband as well!)

Anyway - for the record- it did cost $475.00 to move it 80 miles. And they did a great job.

Now I am asking you to educate me on another topic - humidity. We have searched the archives and read previous posts on the topic, but still have more questions.

Of course we bought the piano in the midst of this summer's heat and humidity and our house does not have central air. Before we got the piano I bought a humidistat and found that our room was averaging 65 to 70% relative humidity. I know that that number should be closer to 45 or so. I discussed buying a dehumidifier for the room, but my husband's concern is that since it is so hot - we have the windows open and that would defeat the purpose (and cost a ton to run). We borrowed a window A/C thinking that would help - but it never really got the RH below 60.

How bad is this? I know the situation will change come fall - but are we doing real damage to her piano in the interim? How long can a piano stand to be in that condition?

Next question - we put the piano in the dining room as the living room has a wood stove insert. (I did read the similar thread of a few days ago.) I think the position of the DR is such that the piano will not get the full brunt of the air from the stove, but I know the house will dry out this winter. For the good of everything in the house - humans included - I think we will be getting a large humidifier for the LR. I have not idea how much humidity that will put out and if it will prevent huge swings in the RH level. Other than causing the piano to go out of tune - what bad things can happen with humidity changes?

Also, my daughter read all the threads on Dampp-Chaser systems and really found no consensus as to good or bad. In any of your experiences, are they better at dealing with removal of moisture in high RH conditions or adding moisture in low RH? Or are they OK at both? Or neither? Which condition (damp/dry) is more detrimental for a piano and should take priority in being solved?

Finally - We have not yet had the piano tuned. Should we wait until Sept or so until things cool down, or is it OK to do it now? It has been in our home two weeks now.

Again, we appreciate all the expertise we have been able to avail ourselves of on this forum.. THANK YOU

I would get a full Dampp-chaser system for the piano - Humdifier and De-humidifier. The winter air will be lot drier than the 70% RH you have now. As you found out, room A/C units are not really enough. Please get a room humidifier for the winter, to help keep the humidity towards 40% (or as high as you can without condensation on the windows). If you have forced air heat, consider a furnace humidifier for the winter. They work great!

Dampp-chasers work well in upright pianos, because the cabinet is enclosed. They are not a substitute for room climate control, but unless you get Central A/C, you are doing the best you can.

In general, it's best to tune a piano in your area 2 weeks after the heat comes on, and two weeks after the A/C goes on. (or in your case when you open the windows)_

No consensus?!?!? Getting a Dampp-Chaser system is one of the best things you can do for a piano. The Baldwin SF-10 at my church has one, my own Baldwin has one, and every single one of the 70 pianos at my grad school had one.

Perhaps it depends on your climate. I don't see them on pianos here in LA -- mostly the San Fernando Valley. Humidity here can go low, but rarely high. Given that we hardly ever run the A/C, but do heat in the coldest months, would one help my piano?

Really?

I've heard only raves about the Dampp-Chaser systems.
So much so that I actually installed one myself on my piano, and let me tell you, it takes a big load off of your mind.
My humidity ranges from over 90% at times in the summer to under 20% in the winter and there is no way I could control that to the extent needed with a full room humidifier and dehumidifier in my house.
Here in the winter it is cold and if you try to go above 20% humidity you get condensation and often ice on the windows.
My Dampp-Chaser system adds humidity when it is too low in the room and removes humidity when it is too high.
Everybody I know who has installed one of these systems either raves about it or at least speaks very highly of it and is very glad that they purchased one.

I just serviced a Steinway B that came from the Eastern (very dry) part of Washington State to Western (Pacific maritime climate) side. In most cases I have seen, pianos that come from Eastern Washington go very sharp after several weeks - 444 would not be unusual. However, in this case the piano was almost right on pitch. It had a full Dampp-chaser system. I have no doubt that it kept the soundboard from drying out based on the tuning.

As a piano tuner, I don't want to tune my piano any more than I have to, so I have a full system. My 9-year-old son has gotten good at watering the piano!

Wow. Thank you for those experiences. My daughter did say that some of the stuff she read seemed to be from when the system was first out and that maybe improvements had been done. But she did read one thing that even said the system was bad as it could cause the soundboard to be one humidity on the inside and another on the outside. Bob mention the system works well in uprights so if that comment she read has any truth to it -maybe that was pertaining to a grand.

Does it make any difference if the piano is played with the top open? It is an upright, but she usually plays with the top propped open a few inches.

Sparky - thanks so much for the specifics. I was wondering how much control they provided and if other methods would be needed as well.

And to repeat a question from my original post (my daughter tells me my posts are too verbose - quite true!!!- and potential commenters won't wade through it all to get to the questions... I was just feeling chatty and decided to update the results of all my earlier posts) other than tuning problems - what damage does high humidity cause?

I understand that too low dries wood and causes cracks, but don't understand the risks at the other end.

I did ask one dealer how long a piano could be in less than optimal conditions before damage occurred and he said as little as five to six weeks. So are we somehow damaging this piano while we are trying to get the situation under control?

Thanks again for your replies.

Depending upon how the sounding board is constructed it is trapped by the rim. Too much moisture and the board will expand until it breaks the crown.

A while back a colleague of mine Jack Houweling dropped by with some materials and we performed some experiments. I have changed the watermarking to reflect Jack’s ownership of the photos.

This is a Picasa web album. Pleased left click on this link and that will take you to the location of the album. Then once there, left click once on the first photo top left, and this will enlarge the photos so that you can read the text below each frame.

It is surprising how much movement there is even with a small sample board....

Here is the link

humidity effects

Marvellous experiments Dan. Loved it!

I had a DammpChaser fitted to my Sauter upright. Tuning stability is now remarkable, with no discernible change for months on-end, even with large fluctuations of relative humidity.
I highly recommend the DC system.

High humidity is necessary to the growth of some nasty things such as mildew, mold, dry rot, and even termites (though it has to be really high for them). If it condenses out, you can get rust on the strings and pins. It makes wood expand across the grain, and wood can crack from being too big as well as being too small.

Wow, great pictures Dan!
It is amazing to actually see the effects of high humidity on the physical swelling of wood.

After I got my piano regulated I had a problem with a note sometimes not repeating (it somehow would get "stuck" internally and not "reset").
It only seemed to do this when the humidity got high.
I've since had my tech adjust it but since I've had the DC system everything seems to have stabilized and even though I installed the DC system the day AFTER I got it tuned (not the best idea I admit) the piano has definitely not drifted as much as it previously would between tunings.

Thank you all for that great information. Those pictures were very telling, Dan. I appreciated the lesson. I will be calling about a DC system on Monday!

Very good 4ed.The problem for you there is with the high humidity experienced in that location will expand the length of the board.

As mentioned previously, the board is trapped by the rim of the instrument, so the board will attempt to rise up as in the photo….

However this rise is trapped by the pressure of the wire strings over top of the bridgework forcing it down; this will crush the crown of the board until such time as the wood fibres break down and the crown collapses.

The DC systems stabilize and create a specific environment for an area of the instrument with great benefits being the result.