Garrett Hack replies: I doubt you will have any issues with your tools. It’s the summer humidity and swings in temperature that usually causes rust. Stored wood won’t care either. But when you go to build a piece of furniture, your wood will not be acclimated to the same conditions as a house (constantly heated) and might be less well behaved.
Jon Siegel replies: As I am writing this in February 2022, prices for fuel have risen sharply. I realize it’s hard to justify continuously heating a woodshop in a garage or outbuilding if you’re only using it on weekends. However, there are many problems associated with a woodshop that undergoes large temperature changes.
Dan Wallace replies: I have a Modine Hot Dawg propane heater with a sealed combustion chamber (doesn’t add moisture) so it works like an electric heater. I have done what you want to do for the last ten years and I’ve even gone as far as dropping the thermostat down to just above freezing until I realized it actually cost me more to bring my shop up to temp. Now I set it at 50° when I’m done. My thinking is that the shop drops temperature slowly and when heating it rises fairly slowly. I find that my cast iron tools take quite a bit of time to warm up so there is no chance of condensation collecting. I think the materials and machines aren’t hit with an abrupt temperature change that would neither add nor remove moisture too quickly.
Bob Couch replies: I also have a well insulated garage workshop and use a 220v ceiling heater. It is hard to answer your question to some degree. All of my tools and machines live in my garage space, however all of my finishes are stored in an adjacent utility room that’s also heated. If your finishes and adhesives are not stored in a warm place, I would just leave the temp no lower than 55°. This also helps with humidity/moisture content. It’s part of the cost of your hobby and pleasure.