What is efficient mean?
The definition of efficient is the following:
1. To Deliver a successful outcome and meets objectives as fully as possible.
Definition of efficient adjective 1(of a system or machine) achieving maximum productivity with minimum wasted effort or expense: more efficient processing of information [in combination] preventing the wasteful use of a particular resource: an energy-efficient heating system 2(of a person) working in a well-organized and competent way: an efficient administrator
An incandescent bulb is 96% efficient as a heater, and 4% efficient as a source of light. A fluorescent bulb is only 60% efficient as a heater, and 40% efficient as a source of light. An LED bulb is only 10-20% efficient as a heater, and 80-90% efficient as a source of light (but that light is usually unidirectionally directed... harder to do diffuse lighting with them).