Traditional space heaters are designed to warm a room, while most infrared heaters warm objects, so neither is inherently more efficient. For heating a room, an oil-fueled space heater provides better efficiency.
Infrared heaters generate infrared light, which warms objects it comes into contact with, including people. Because of this, infrared heaters can warm a portion of a room. Space heaters, on the other hand, produce warm air and blow it through the room. People and objects take a longer time to warm up, but the entire room eventually warms. If several people are in the room, traditional space heaters are typically more effective.