They don't "produce" any moisture, they do cause the moisture to condensate and either exit the cooler via the drain, or if he drain is plugged the moisure will pool on the bottom of the cooler. I plugged the drain on my unit and directed the condensation into a container of Kitty litter. After a bit the cigars and cedar drawers all stabilized and now I remain at 65% RH which is where I want it. Basically maintenance free now other than rotating drawers every now and then to avoid any dead spots...I have had one cigar get a mold spot but that was early on...all good now!