Best of luck - I lost snakes twice (separate incidents - not my fault) - fortunately I found them again (right down inside the sofa!!) LIke the others have said, warm places, they have even been found inside people's trainers curled up, anywhere that seems a nice little hide. Snakes don't often go much further than where they escaped from so hopefully he'll still be in the same room. I hope you get him back soon.
dark warm places, was the door in the room locked? or closed? he may still be in the same room, you can leave food out this sometimes works. other than that id take the room apart myself, ive had to do this a few times haha.