The previous owners of my house built a walk-in meat locker in the garage.  It is really unique and has the overhead rail and (Texas Chainsaw Massacre) meat hooks.  It is also lined with syrofoam and has a cooling system.  Wouldn't this make a great walk-in humidor?  The problem is that in Idaho our temperature fluctuates from -30 to 100.  It is currently in the 20s here and the inside of the meat locker is in the 40s.  Any suggestings on how to raise the meat locker temperature to 70 in the winter?  The humidity would be easier to control.

Photo of meat locker with my camping supplies.

Are there electrical outlets inside by chance?  I would probably put in a oil based radiator heater that has a thermostat and a large electric humidifier.  Good luck, that will be awesome if you can find a way to make it work.

There is electrical wiring.  I was thinking that a simple heat lamp would raise the temperature.  How much I don't know, but I intend to test it out.

mold spores would worry me to no end.

You would have to line the inside with a a couple vapor barriers then put Spanish ceder over that.

You would have to sterilize the floor and seal with pain sealant, and let it air out for quite a while.