I'm finding conflicting information but it sounds like fiberglass has an R-value of 3.4/inch while rigid foam is 4-6/inch depending on the type. We'll see what they have at the store. Plywood on either side would add about 1.5 to the R-value.
Any thoughts on flat panel heaters like the sweeter heater?
https://www.sweeterheater.com/overhead-model
I wish that sweeter heater gave the temp range in which it runs.
Have you gotten onto any of the Facebook pages? Alaska Flock Talk or.... ...... ...... there is one just for Fairbanks I think.
I would ask on those threads.
I would be good to get first hand knowledge .