A rotating space heater used 1,400 joules of energy while heating a room. Of that total, 896 joules produced thermal energy, 181 joules produced kinetic energy, 203 joules produced light energy, and 120 joules produced sound energy. What is the space heater’s efficiency?

The space heater's efficiency is 64.0%. (896 joules / 1400 joules = 0.64)