https://en.wikipedia.org/wiki/Vacuum_insulated_panel https://en.wikipedia.org/wiki/Vacuum_insulated_panel Looks like the thing. So, yeah, very good vacuum. It's

https://en.wikipedia.org/wiki/Vacuum_insulated_panel https://en.wikipedia.org/wiki/Vacuum_insulated_panel Looks like the thing. So, yeah, very good vacuum. It's apparently decades for the lifespan, but much of it boils down to the materials being used.