Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Is 52% - 62% humidity okay?

Hi everyone-

I have a 1995 Petrof PII (7ft 9") - I live in Northern California- climate is best described as Mediterranean. I just bought the piano about 2 months ago- I was living in one house, where the humidity was around 50%, but now just moved into another house- this house is a bit closer to the woods (not like a forest or anything- just a stream with vegetation) and it gets less sunlight. In addition, the days have been cloudy lately (no rain) and now the humidistat has been reading in the low 60s and upper 50s. I'm a little nervous and am wondering if I should go out and buy a room dehumidifier.

The piano soundboard is clean except for one ridge (slight crack) on the upper side of the soundboard where one soundboard seam is. It was like that when I bought it. No noticeable buzzing or anything like that. From the bottom of the piano, it also is mostly smooth if you run your hand over the seam.

I should also mention that the humidistat I purchased was from Home Depot- not really expensive...

Also, I think installing a Dampp Chaser is out of the question, as the piano has the PianoDisc system installed underneath with playback and record capabilities.

Any thoughts?
thanks!

Look into whether an ultrasonic room de-humidifier would work for you. Set it to keep a 50%RH. Then turn it off in the winter when it is drier.

It probably is not a problem as long as the humidity stays at the same level year-round, which is generally the case here in the Bay Area.

Hello

data from the Petrof web site :

Environment temperature°C Minimum relative air humidity% Minimum absolute wood moisture% Maximum relative air humidity% Maximum absolute wood moisture%
10 30 6,6 55 10.7
15 31 6,5 56 10.6
20 32 6.5 58 10.7
25 34 6.5 60 10.8
30 35 6.5 62 10.8

so 30° to 35% to 62% HR is accepted


60-65% are on the high side of hygrometric specifications but without problem for high temperature, as the wood Humidity is then similar 6.5% at 30°-35%HR = 15° and 31%HR

A wood moisture about 8% is ideal. . Now the less the changes the best it it.
Winter is dry season generally speaking.

steel Strings corrode "a little" faster above 60% - still not really bad if not with a low temperature.

Greetings,
Congrats on your piano. Post pics & recordings some time! (that's your biz, so it should be run of the mill to do so, I suppose)

Anyhow, somebody mentioned those low cost hygrometers available from home depot on this form ~ 5 mo back, so I went out and got one (Acu-rite brand) . I put it along side two pro-grade, not especially high end, but certified calibrated laboratory meters (Onset/Hobo brand). For the statistically insignificant sample size of 1, the home depot meter was not bad at all, measuring 1 or 2 %RH absolute difference from the certified calibrated meters. (28% vs 30 % in the image below- which is within the tolerance band of the accuracy of the Onset/Hobo meters.


best wishes-

I also purchased a couple azurite's and tested spot on in a certified humidity chamber.

My Florida piano (Chickering 145) hasn't had any humidity problems and this piano started in Texas in 1927 before moving to Florida. If you are by the ocean, like the Chickering was, some verdigris on the brass parts and faster rusting of the strings is to be expected. My soundboard has no cracks. Rather miraculous for an 85 year old piano.

Pianos in Florida don't suffer much from soundboard cracks due to the relatively high humidity year round. We installed a humidifier in our concert hall to combat dry air during Florida cold spells during the winter. The RH in there is about 62% year round since the humidifier installation. The temp is about 72 F. No issues for the piano, except I've voiced it a bit brighter to account for the moisture in the hammers.