Had no clue where to stick this so I've gone with Engineers , since I've just been googling R ratings of materials! Just rushed to mount a radiator on a wall, a cheap nasty 'designer one' that was a pain to fit - stood back to admire my work and instantly realised my mistake...there's an integrated fridge on the other side of the wall. I went to check the wall for insulation since there's not really anywhere else to place a rad in the room and the wall appears to be just a sheet of 18mm ply and one, possibly two plasterboards on stud. It's directly on the other side of the airflow route/space for the fridgefreezer. I suspect the answer is it can't stay there but optimistic the plaster will deflect enough of the heat and the ply's not a great conductor so wondering if I'll get away with it. What are people's thoughts? I don't really want to test it and plumb it in and then have to remove it if it's an obvious no no, but might have to if there's a fair chance it's ok.