Garage heating questions (temp/insulation)

[GreenScrew]

I'm in Wisconsin and the garage is 28x34 detached with a second story bunkhouse for overflow sleeping quarters. No running water. I normally just heat the garage when I'm working in it but I'm considering keeping the garage heated this winter and have some questions:

What is the lowest temperature normally recommended to keep the garage at? My (wifi) thermostat only goes down to 40, I was considering keeping it low, maybe 45 or lower. Any concerns for this?

I'm also curious about the insulation. The garage is insulated with kraft faced insulation, the paper faces the heated garage space. Keeping in mind there is "living space" above that I don't intend to keep heat unless it is used which is only a few weekends during the winter. Is this the proper way that the garage should be insulated?

 

[TractorJeff]

My neighbor has a waste oil furnace which he keeps at 45 degrees when he isn't out there.
I rebuilt an engine one winter in a gas fired Modine heated garage that the owner insisted be kept at 45 degrees.
As far as the Kraft faced paper, yes the paper should face the inside of the garage.

 

[astroracer]

I keep my shop at 50 degrees when I'm not out there. I tried it for a month or so at 45 but the tools were just to cold when I would want to use them and it took longer to get everything warm. 50 seems to be pretty good for initial warmth and the shop warms up quicker when I do bump the stat up to 60 or 62 to spend a day out there.
I've been heating the shop like this for 24 years. Try it at 45 for a while but I think you will probably bump it up a bit after you get some time into it. Really made no difference in the heating bill (forced air/natural gas).
Mark