I used welding Blankets over my pellet grill in the winter. It helped some but probably didn’t save enough money in pellets to justify the cost of the blankets.
Just thinking here, but aren’t the pellet smokers designed to breathe? I’d think any sort of wrap would restrict the smoker’s ability to move the smoke properly or maybe more importantly to keep the pellets lit. Since the pellets are smoldering, not burning with a flame, the may be easier to extinguish.
I’m pretty sure my smoker has insulation between the outer skin and the inner walls. That should be adequate.
been using pellet grills for over 10 years and never had a issue in the winter and never used a insulated cover. sure its going to use more pellets but pellets are cheap and dont bother me