Saturday, September 17, 2011

An LED Light Bulb

There may be a lot of fuss about the general availability of 60-watt replacement LED light bulbs, but LEDs are still more efficient for lower power levels. Today I went searching for a replacement for a burned-out 25-watt light bulb in a hallway. The replacement is a 3.5-watt LED bulb made by Philips and sold at Home Depot for $12. Given the power savings, this seemed a better choice than the $3 option of another incandescent bulb. Saving 21.5 watts, the difference between the 25-watt incandescent and the 3.5-watt LED, translates to saving about 1¢ every 3 hours the light is on.

I was skeptical of the LED bulb’s claim of replacing a 25-watt incandescent bulb. It generates only half of the light output, so what kind of replacement is that? But it was easy to see why it works after I installed the LED bulb. Hardly any light from the LEDs goes onto the ceiling. Most light sources waste most of the light they generate by radiating it indiscriminately in all directions. LEDs, being smaller, can more easily direct light where it’s needed. The result: a hallway lit with an LED light bulb using one seventh of the power of an incandescent light bulb, but producing light that is nearly as bright.