Infrared heaters are efficient at converting electricity to infrared light, but their overall efficiency varies significantly based on their design and how they are used. They can be efficient at heating people but aren't as efficient at heating rooms.
Traditional heating systems warm the air in a room. Infrared heaters heat objects reached by the infrared light. The heat absorbed by walls and objects warms the air but typically does so inefficiently. People sitting near an infrared heater warm up even if the room does not. Still, those in cold areas typically see superior results and cost savings by using traditional heating options.