A few comments on the Goldenrod. Prior to installing one in my large gun safe I did a lot of research on the subject. I'm convinced it is the best solution considering other options. If properly located in the bottom of the safe it not only heats the interior of the safe but also creates convection air currents, both of which prevent any moisture from settling on the firearms.
A word of caution to those of you using other sources of heat, such as light bulbs. It takes very little heat to raise the internal temp in a safe. 8 to 10 watts is very adequate for most gun safes. Much more wattage and you take the risk of drying out the gunstock wood. I have read of documented cases where lightbulbs in the 40 to 100 watts was used, resulting in cracked stocks over an extended period of time.
By the way, a great way to light the interior is to install one of the rope lights along the corners of the shelves. They are available at most hardware stores and many other retails stores such as wal-mart, Sams, etc. It does a great job in my safe as it was long enough to string above each shelf. Sure beats grabbing a flashlight each time while trying to move things around to look for stuff.
Wayne