Accepted Answer
It just depends on what you're trying to accomplish with the device. As a producer of work, it is 12/40 = 30% efficient. As a heater, it is 28/40 = 70% efficient.
It just depends on what you're trying to accomplish with the device. As a producer of work, it is 12/40 = 30% efficient. As a heater, it is 28/40 = 70% efficient.