I'm happily retired so I spend a lot of time in my shop: a 12'x24' portable building with insulated walls, Styrofoam panels under roof, but no insulation under floor. Cold weather is not a major problem around here (SE Louisiana), but we do get a few chilly (below freezing) days) --- enough for me to long for some additional heat. My "dust collection" system consists of a small shop vac and a box fan with filter, so obviously the shop does get dusty at times. I would like to add a safe (no open flame?) heater that would only be on when I'm in the shop. Would one of those oil-filled radiator style units be OK? Or maybe a ceramic heater?