Depending on the freezer, putting a hole somewhere and sealing it up really well is just as good as the walls and insulation that were in there before. I did th

Depending on the freezer, putting a hole somewhere and sealing it up really well is just as good as the walls and insulation that were in there before. I did this to a chest freezer that wasn't terribly expensive and I haven't ever noticed that the outside of the hole is any cooler than surrounding areas, nor did I notice that it had to work any harder to keep it cool. That being said, I didn't exactly exhaustively detail the before and after performance of the freezer either. I used the smallest drill bit possible that would let me get a probe in there and everything else is external of the freezer down by the compressor motor where there is a lot of extra room- and input power to tap in to.