Does using a light dimmer save electricity?
If you are using an electronic dimmer rather than just a variable resistor, then yes, it uses less power than when it is operating at full intensity. But it is much less efficient than a more efficient form of illumination operating at full efficiency, or even a small incandescent night light bulb operating at full power, therefore at full efficiency. Replace that 40W incandescent by a 10W full-spectrum compact fluorescent lamp, and you’ll get the same light output with 1/3 to 1/5 of the power consumption, and you won’t need to dim it and won’t risk tripping in the darkness. It’s a good technology for a light that is used for hours at a time. It’s a bad technology for something like a bathroom where it’s used just for minutes at a time.
