We dress Fergus in a singlet, long sleeve onsie and bonds wondersuit for sleep. Then put him in a 2.5tog sleeping bag. He's nice and toasty but not to warm. He's too wriggly to stay under his blanket and sheets overnight nowadays so the sleepingbag is a must. We don't leave his heater on overnight, but do warm up the room while he's in the bath before bed.