I just bought one of these so-called dehumidifier rods yesterday for my safe. After bringing it home, and thinking about it a little.....I kinda feel taken. Here's why....
I was told that these heating rods keep a constant temperature in your safe, preventing the temperature changes that cause moisture in closed areas. Well, being that this heating rod stays on all the time, I see NO way that it can prevent temperature changes. If we have a high of 85º and a low of 65º for example....it will just be about 70º in my safe at night and 90º during the day. So how is it keeping the temp. constant? Am I missing something here????

It doesn't keep the temp constant, not designed to.The Dehumidifier rod causes the air to circulate within the safe, thereby preventing damage associated with moisture.
Since steel is characteristically cold, moist air will condense quickly on its surfaces.
The presence of the Dehumidifier will maintain a constant level of warmth
in the steel and virtually eliminate all moisture condensation. Similarly, vaults made with concrete or block walls will tend to allow dampness to seep through wall pores.
The Dehumidifier works by distributing a low temperature heat to the air inside the safe and will raise the temperature of all gun parts 2 to 3 degrees which virtually eliminates all moisture.


[red]Evil-Beagles[/red]

A cheap night-light does the same thing.  I have been doing it for years.  A fresh bulb once a year and the $3.00 set up has lasted me 10+ years now.

OSA

Personally I use desicant(Silica gel), because living in Arizona (Phoenix area) it never gets cold enough or has high humidity. I have no fear of rust.[:)]
If it ever drops to real cold temps in the winter I have the heat on. If you live in a high moisture area like in New England I would recommend it though...