Good suggestions about food & heat to lure him out.
My juvie guy occasionally moves beyond his "supervised area" and disappears in the house. Fortunately, he always gives himself away by huffing when he hears noise. I take a plastic shopping bag through each room, crinkle it, then listen for him. He's usually found within minutes... usually in a dark corner under a heavy piece of furniture.
Good luck, and I hope you find your little guy soon!