99% of my tools live in my heated/air conditioned attached garage. Once I remodel the basement 99% of my hand tools (planes, scrapers, chisels, etc) will be moved indoors to my hand tool area; until then in the garage they live.
Recently I noticed a hint of surface rust of a few of my planes and wondered, if I were to install a 15-40w (tungsten) light in the tool cabinet would it generate enough heat to keep condensation away. I figure so long as the tool is slightly warmer than the ambient temperature condensation will not happen. Example, garage was 55* this weekend, if the tool is 60* the tool wins.
For the record it did take nearly a year for this to become noticeable but my heart did sink with my LN #8 (anniversary gift) was showing signs of rust.
Ultimately, the question is about heating the cabinet holding the tools, light bulb or not.