I have an unheated warehouse building with a small bathroom in the middle, maybe 4 feet by 5 feet. Since I only go there 2 or 3 times a month for an hour or less, I never turned the water on. I just have five 5 gallon water jugs that I fill the toilet with after each use. That much water lasts for a good 6 months or more. From about November to April I drain the toilet to prevent freezing and just don't use it over the winter. Thought it might be convenient to be able to use it year round so I'm thinking of getting a portable plug-in heater. I just need it to heat the space to 40F max to prevent the water in the tank and bowl as well as the jugs from freezing. The heaters I've seen don't have an actual temperature setting, just maybe low to high. Are there any that actually show 40, 50, 60 degrees, etc.?

This may not seem like a big deal, but I'm not too experienced with these things and would appreciate any thoughts or insights before I proceed. I'm trying to figure out if it would be better to make a small hole in the drywall or in the baseboard of a wall I want to run an extension cord through. Why do I want to do this? One room is lacking accessible outlets where I need them, but there is an outlet nearby in the adjacent room. Rather than having an electrician install a new outlet, I think it might just be easier to create a small hole and run an extension cord through. Note that there is no wiring or plumbing in the wall I want to make the hole in. So I'm trying to figure out if I should make the hole above the baseboard in the drywall, or if I should cut right through the baseboard so the hole is sturdier and closer to the floor. Again, thanks for any thoughts or insights you might have.