what electric heater is more efficient, oil filled or instant?

Answer 1

electric

Answer 2

Each type serves different situations.
The oil filled is less costly an will warm an enclosed room
The instant one requires that you sit in front of it for a small space
It also is more costly to run

Answer 3

they both use electric heating elements and use exactly the same amount of electricity when the wattage is of the same rating. One provides a more even heat the other a more directed heat. both will cost the same to run