My hygrometers are analogue, pics are just up a few lines, I have 3 to deal with inaccurate possibilities.
I’m not worried short term, this is purely a long term concer, as I’m not likely to get a guitar of this expense again. I think I’ve found a solution but, for next year. Basically a hermetically sealed cabinet for instruments.
R
Humidity can also vary a lot by location inside the house.
My centrally located thermostat (whole house humidifier ) reads 30% RH, a stand alone humidistat reads 38% one room over (pretty open floor plan), and in the walkout basement where my guitars are it reads 35% on the humidifier itself, 6 feet to the right at 4 ft shelf height reads 33% and at guitar stand level (maybe 1 ft?) right between the two guitars (and only 1 ft to the left of the shelf) reads 45%.
Yes, I have moved humidifiers around and correlated the readings, so these are all consistent. I actually like to run a small quiet desk fan in the guitar area of the basement to even it out a bit. I must get a basement floor bump. Temperature is more uniform, although I am sure that is part of it.
We have a dehumidifier in our house, which keeps the relative humidity in check.
The experts claim a healthy RH is no more than 60,%mold will kick in around 70%
Our dehumidifier is set to keep things at 55% and my guitars all seem happy, I keep mine on a stand and never put them in a case
RH levels work hand in hand with temperature
Our 55 is at about 20 celcius
Please note that we are talking about the relative humidity. It is depended on the temperature. So the same amount of water in the air can be 90% RH outside (when temperature 3°C) and 50% inside (when room temperature is 22°C).
(the numbers are apx from my head, to get the exact numbers one would have to look at Molliere chart)
I was told that the OK range for the guitar indoors (temperature 21-22°C) is between 50-60 % RH. Anything less then 40% is problematic as guitar can dry out.
I am located in Slovenia (EU) and we have quite high summer moisture, but the AC works that out (beside cooling AC also takes out moisture). At winter time we can get less then 40% RH indoors, which is why I have humidifier and run it to have around 50% in the part of the appartement where I have guitars.