many thanks. One footnote, I have 3 digital hygrometers, they all claim to be + or - 2%... I have seen as much as 10% variation between them!! My electronicly controlled unit I tend to trust because it was so darn expensive (100 bux). So I would be leary of a measurement from a single source. If you know folks who have a digital hygrometer, I would swap and trade a few and perhaps average the readings between them to help calibrate yours. i.e., if you're reading 70, and you're 6 to 8 on the low side, your pushing 80%, very bad...