Dry lumber will pick up moisture if stored in a moist place. Beautiful wood floors will cup when ambient conditions change. Furniture suffers severe damage when moving from a wet climate to a dry climate. Chairs may have loose joints, cabinet doors may not close. Even a piano can be out of tune from too much moisture. For lived-in areas at 70oF (20oC) and 35% rel. humidity, wood stabilizes at 6-8%. Changes of these conditions can cause shrinking, cracking or warping. We recommend the PN Hygrometer for low relative humidity readings and a short response time.