Adding Insulation and a Vapor Barrier to My Barrel Sauna

Bought a barrel sauna kit that came without much insulation, which is fine in a mild climate but not in Anchorage winters. Cutting rigid foam to fit a curved barrel wall was more fiddly than I expected — lots of small panels rather than a few big sheets.

Made a real difference in heat-up time and how much the heater had to run to hold temperature once outside temps dropped well below freezing.