Posted by Daniel Hall on October 24, 2007
The journal Nature reports [subscription required]:
When a newly expanded Wal-Mart store opened in Burton, Michigan, last month, it seemed like just another case of American gigantism…
But over in the frozen-food section, something more interesting than mere wretched excess was happening. The display cases are lit not with fluorescent bulbs, but with light-emitting diodes (LEDs). The LEDs last longer than the fluorescent bulbs they replace — and are so energy efficient that Wal-Mart expects to save $2.6 million a year by installing them in 500 stores nationwide.
…LEDs make sense for Wal-Mart’s freezers because fluorescent bulbs are less efficient at cold temperatures, whereas LEDs are unaffected.
Who knew? The article goes on to say that LEDs haven’t quite caught up with fluorescent bulbs at regular temperatures, but they’re expected to soon:
An incandescent bulb produces about 20 lumens per watt of power consumed, and a compact fluorescent produces about 60 lumens per watt. Commercially available LEDs now average about 30 lumens per watt, but over 100 lumens per watt has been reached in the laboratory. Most people expect LEDs to outperform fluorescent bulbs within a few years…