Relative Humidity level below 35% is arid and wood will dry out and shrink (and sometimes warp/crack in the process). Above about 60% and it can swell, but not a major issue outside of delicate/fine furniture. Keep it below 70% to inhibit most mold growth.
45-55% RH is a good target for human comfort, wood interior comfort, and discouraging mold.
45-55% RH is a good target for human comfort, wood interior comfort, and discouraging mold.