Thin material with high thermal insulation capability

[witten]

The insulation only slows down the warming up of the pantry, it doesn't keep it cold. So you either need to cool the pantry or remove the heat from the fridge so that the heat doesn't want to move into the pantry

The pantry is not a closed system, it is cooled down through the other walls.

 

[weberduo]

The pantry stands with its side against an exterior wall facing north. The pantry is okay in the winter when the refrigerator doesn't work so hard. The door is quite thin and not completely sealed, so it might also need fixing, but the biggest problem is the immense heat from the refrigerator's side.

 

[Anonymiserad 168520]

The pantry is not a closed system; it is cooled through the other walls.

If we are to be picky and purely theoretical, it depends on where you set the boundary conditions...

If we stick to the topic, the OP has already written that it gets warm in the pantry because of the fridge, so the other walls are not cooling sufficiently against what the fridge heats. This is also the reason why I responded the way I did.

 

[Anonymiserad 168520]

The pantry is positioned with its side against the outer wall facing north. The pantry is okay in the winter when the refrigerator isn't working so hard. The door is quite thin and not completely sealed, so it might also need to be fixed, but the biggest problem is the intense heat from the refrigerator's side.

Possibly, insulation might make it more resistant to heat penetration and the other walls might cool the pantry sufficiently, but there is no guarantee and it could be a lot of work without results.

If the heat behind the fridge cannot dissipate elsewhere, it's only a matter of time before the refrigerator continues to heat up the pantry.