Refrigerator insulation adding?

I bought a roll of foil faced fireproof (or at least resistant) auto firewall insulation from JC Whitney and lined the entire box the fridge fits into. Not only is it way better insulated, but all that tinder wood is now covered.

I added 2" on all sides to mine and it works great even on elect. in triple digit heat.
Make sure the roof vent isn't obstructed either.

I added some spray foam insulation when I had my frig out. Initially I did this to hide the exposed screws that were poking thru from the adjacent cabinets after one of them got the back of my hand. I wound up spraying up to the insulation batts and adding a bit more batting where insulation was missing. It looked really nice when I was done but I didn't really notice any change in the performance. I didn't really have a problem with cooling to begin with, but no harm was done either.

Make sure you don't overstuff the space with fiberglass batts - that will actually reduce the effectiveness of the insulation,