Definition of efficiency (from Google): the ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in.
Heat pumps are >100% efficient.
Usually, we cannot convert all input energy into useful work, so efficiency is always <100%, because of energy losses, which are producing waste heat. However, in case of heater, heat is the "useful work", so electrical heaters have "impossible" 100% efficiency, while heat pumps have even more "impossible" >100% efficiency.
Heat pumps are >100% efficient.
Usually, we cannot convert all input energy into useful work, so efficiency is always <100%, because of energy losses, which are producing waste heat. However, in case of heater, heat is the "useful work", so electrical heaters have "impossible" 100% efficiency, while heat pumps have even more "impossible" >100% efficiency.