Every winter, I deal with keeping humidifiers in my house to prevent the air from becoming too dry. It, not only, prevents static electricity, but helps us to feel less dry, and hopefully prevent colds. But, what about our harps and other wooden instruments? In my music room, I strive to maintain a humidity level of around 45 to 50 percent. Smaller instruments, such as banjos, ukuleles and other instruments made of wood need to have humidifiers stored inside their cases to prevent cracks from excessive drying of the air. Hope this info helps.
We also aim for 45% minimum in our house, which takes some work, as we heat almost exclusively with a woodstove. 50% really takes some work, but we’ve gotten close. I have four harps, and actually I keep an Oasis humidifier in my therapy harp case, as it’s such a small harp. All other instruments, guitars, mandolins and such have an Oasis in their cases as well, and we’ve been pretty pleased with them.
During winter I have kept my guitars (especially the solid wood acoustics) in a room with at least 40% humidity. My SO’s harps will be kept there too during winter. I could increase the humidity to more than that but there is a risk - depending on how cold it is in your region (it’s cold where I live), and in particular how well insulated your house is, there is a risk of condensation inside the walls if a) it’s very cold outside and b) the humidity level inside is high. Condensation must simply not be allowed to happen. If it does, it will soon result in mould, and if that should happen it’s basically fatal for the room/building. Fortunately my house is very well insulated so even at 45% I’m not too worried, but I do not try to achieve the natural humidity level I see in summer, which is at least 50% -60% around here. If there is a problem achieving the necessary minimum humidity level during the occasional cold spells (extra cold, extra dry air) I will simply reduce the temperature of the room where the instruments are stored. This naturally increases the relative humidity, without risking condensation.
For the last decades, at 40% or so, maybe up to 45% but never below 40% for long term storage, my solid wood acoustics have never had any issues so I trust my SO’s harps will be fine. Particularly as the soundboards of her harps are laminated wood.
All good advice! Wood loses and gains moisture to match the air around it, so if the air is too dry, the wood can shrink and crack. In our part of the world, winter tends to be the riskiest time of year, since pulling cold air from outside and heating it up inside your home causes the relative humidity to drop pretty drastically. 40-50% relative humidity is widely considered to be a safe range for solid wood musical instruments, and the further below 40% you go and the longer the instrument spends in a too-dry environment, the greater the risk of a crack developing.
It’s also worth mentioning that high humidity can cause problems for instruments as well. If a soundboard gains too much moisture, it can swell and warp. So if you live in a particularly humid environment, you might need to take steps to dehumidify in order to keep your instrument in the 40-50% range.
Thank you for all this great info. I feel better about not getting much above 40%.