<HTML> <HEAD> <TITLE>Re: [CAUT] Hygrometers</TITLE> </HEAD> <BODY> On 11/15/07 7:13 PM, "Greg Newell" <gnewell@ameritech.net> wrote: <BLOCKQUOTE>Paul,                40-45% at what temperature? At 50 degrees, for instance, that would be quite wet. Greg Newell </BLOCKQUOTE> Hi Greg,     Actually, 40-45% RH at 50 degrees F is a fairly low “absolute wetness” level for the air. If you don’t change anything except temp, and raise the temp to 70, the RH will drop to something like 30%. (The hotter air could hold a good bit more moisture. RH is a measure of how much it holds compared to how much it CAN hold).     RH is a fairly useful measure for how much water will move how fast between the air and wood that is not acclimated to that RH (has a higher or lower moisture content than would be a stable state in that RH environment). If you vary the temperature, but keep the RH constant, the wood will stay pretty constant (maintain the same moisture content), at least within normal interior temperature ranges. But that means adding moisture when heating, or subtracting moisture when cooling. Regards, Fred Sturm University of New Mexico </BODY> </HTML>