Hygrometers

[Norm66]

I have 9 hygrometers. 1 digital Fluker's thermometer/hygrometer, 1 cheapy double dial, 3 analog silver ones from PetCo and 4 new brass ones I bought from Amazon (they're for humidors but what the hey?).

Problem is they all have different readings. I put them all on a plate in a closed tub with water in it hoping for 100% humidity but I'm not convinced that will work.

Is there a method for calibrating? Of them all I would trust the digital the most since it had the lowest reading (36% IIRC) out in the room and my house is notoriously dry. I'm considering just calibrating them all to that one. What do you think?

[youngster]

I would calibrate them to the digital definitely.

[jarich]

You can buy cheap calibration kits online; Amazon for example has a few. They are about $15 and you can use them repeatedly. Its the only real way to know what they should be at.