Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Is 30% relative humidity a problem?

I bought a cheap digital hygrometer. I know it is probably not very accurate (it claims to be +-4 within 30 to 70 % RH), but it is just to get a general idea and to see if humidity rises or falls and to see the difference between winter and summer here.

It says there is about 30% RH in my living room and near my piano at this time of year. Is it so low that it is a problem?

I don't how high it will be in the summer, but from what I can tell from Danish search results, indoor relative humidity would fluctuate between 20% and 80% across the year, more typically 30% to 60%, depending on how much you heat in the winter, how much you open windows and replace indoor air with outdoor air, how much you generate humidity by showering, cooking etc.

Yesterday I tried to hang wet towels on the two heaters in opposite ends of the room, and RH rose to about 34% and then slowly fell again to be back at 30% this morning.

I guess I will have to get a room (de-)humidifier or even a Dampp Chaser, at least when I get a grand. It just seems as such an invasive procedure to the piano to install it. Can a Dampp Chaser be removed again without damage to the piano? Can a Dampp Chaser installed in an upright be removed from the upright and installed in a grand?

30% is indeed on the low side. With a DC, you can keep the RH higher throughout winter (near the soundboard). The only "damage" created during installation is a few holes in the wooden beams, so no big deal.

Humidify the room first. It is the moisture in the air that conducts the heat so you will feel better too. Consult with an HVAC person to know what the inside RH level should be for the outside RH and temp, there is vapor pressure to worry about. Rods and humidistat for sure for the summer season.

So are soundboard cracks.



Why would you want to remove it? And, well, you create screw holes in the beams when you install it, so if you consider that damage....




No. There are two different upright systems and two different grand systems:

5PS-50-SB: For most uprights.
BSV8PS-SB: For uprights where an internal system is not possible. Dampp-Chaser has a list of pianos that require this system.

G6PS-38-SB: For most grands.
G7PS-38-SB: For concert grands.

The grand systems also come in a 50 watt version. Special under covers are available for additional humidity protection, and also hide the system from view.

If I could get by with a room humidifier, that would be simpler and more elegant. I don't know much about room humidifiers, though. Which type to get, if they're noisy, how many watts they consume, if I can place it close to the piano etc.

I agree to humidify the room first. Get a large floor model or have one installed on your heating system. Don't be surprised if your house requires 10 or more gallons per day.

Humidity levels of 30% for a few days are not a big problem. It takes several days to dry the wood and it will take on humidity much quicker. So raising the humidity in the room for a few hours to around 40% every couple of days will reduce the risk of damage. You won't need to run any room humidifier constantly. Just for a couple of hours.

Wood takes on humidity about five times as fast as it gives it up. That is why protecting against high humidity spikes with the dehumidifier system is so important and valuable.

In my first years as a college student I had the mundane chore of keeping the choir room humidifiers full each day for the two Steinway Bs. 2 units and 10 gallons a piece. Needless to say I was far more slim and trim in those days.

I agree with the room humidfier. It is more effective to controll the air the piano is in than it is to controll the air in the piano. That said, my concern lies with the water used in the humidifiers. When I walk into a room humidified with city tap water, I can smell the chlorine. My nose does not like it, and I don't think that the stuff does the piano much good either. I suggest distilled water, but this can be an expence. Perhaps an activated charcoal filter would work well enough.

If the dissolved gasses in tap water such as chlorine bother anyone-take the bucket of water you just drew from the tap outside for 20 minutes before pouring it in the humidifier. Most of the gasses will have left by then.

Disclaimer: I'm not a piano technician.

What I will do on occasion during the winter months when the indoor relative humidity approaches 30-35% (It rarely goes below 28% in my house.) is place a large pot on the kitchen stove [cooking range] filled with water and let it simmer on low heat keeping it topped off. I only need to do this when the outdoor temperature sinks into the teens (F). I can easily, albeit slowly, bring up the humidity [At the piano in an adjacent room.] to between 40-45% using this temporary humidifying method. It's cheap and it works and makes the overall living comfort level nice and toasty. The worse part is cleaning the pot afterwards of calcium scale (hint: use vinegar). Just a thought as it would work in an emergency if that's the case.

I have spoken to a AC/heating expert about a whole house humidifier and their recommendation FOR MY HOUSE was it wasn't necessary and would likely not be worth the expense since my house didn't suffer from extreme low humidity (<20%).

There is no chlorine used in the tap water in Denmark anymore, so that is not a problem.