I installed a heat pump water heater a couple years ago in the basement shop, it also acts as a dehumidifier, with a drain required. I have been very happy with it, saves a lot of money on hot water for the house. It did make the shop cooler which is nice in the summer, not so much in the winter so I added a small fan to circulate warm air from behind the wood stove into the basement.
This has solved all my rust issues but If I think something needs extra protection I wipe it down with a rag that has a little gun oil or machine oil on it.