How fast can LEDs replace fluorescent light?

Lighting Science Group says it will have retrofit LED bulbs out later this year that can pay their replacement costs in one year. Purdue scientists recently demonstrated a way to make LEDs on metal-coated silicon wafers, saving on manufacturing costs.

Recently I spent an afternoon changing all the light bulbs in my home to fluorescent devices.

It's not mandatory in the U.S., but it saves energy. In places where it is mandatory, like England, protests and hoarding are breaking out.

Turns out this may be an interim step. Bulbs based on Light Emitting Diodes (LEDs) are coming on fast. (Diagram of how LEDs work from the U.S. Department of Energy.)

Lighting Science Group (formerly Lamina Ceramics) was at the Clinton Global Initiative this week saying it will have retrofit LED bulbs out later this year that can pay their replacement costs in one year.

LEDs claim to last 10 times longer than conventional bulbs and save 80% of their energy costs.

The problem for LEDs against fluorescent bulbs has been one of cost. LEDs cost a lot to make.

Early this year Purdue scientists demonstrated a breakthrough, making LEDs on metal-coated silicon wafers, dramatically cutting manufacturing costs. This follows by two years another breakthrough in North Carolina that dramatically increased the light output of LEDs.

LEDs have been around for 50 years. A layer of electron-rich material is placed on a layer of electron-poor material, creating a junction. Run electricity across the junction and photons are created, which can be in a variety of colors.

Both conventional light bulbs and fluorescent lights, like those I just installed, are essentially tubes. LEDs are more like transistors.

About 14% of all the electricity generated in the U.S. is used for lighting. That's about 526 billion kilowatt hours. Lighting Science says that if we replaced just one common bulb in our homes with one of their LEDs we could save 9.6 billion kilowatt hours.

A drop in the bucket compared to total U.S. electrical consumption, but you won't have to change the LEDs very often, either. So add a savings to your knees.

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