Scientists are developing solid-state light devices, made of light emitting diodes (LEDs), to replace the energy-wasting light bulb.

LED Advantages

Energy consumption: In an application such as a traffic signal, LEDs use 92 percent less energy.

Light production: LEDs produce more lumens per watt than an incandescent bulb. A single watt of an incandescent produces 11 to 13 lumens. Packaged LEDs produce about 60 lumens. That’s equivalent to fluorescent bulbs.

Long life: LEDs last at least 10 times longer than incandescent bulbs.

Durability and safety: LEDs are solid-state light producers, which makes them better able to resist vibration and impact. They also don’t require a breakable glass bulb or tube, don’t contain poisonous material — such as mercury — and are usually not hot to the touch.

Applications: Because LEDs are more capable of producing light on a very small scale, they are the most practical lighting in microelectronics. They’re also good options where size or weight is a concern.

Directional accuracy: LEDs emit light in only one direction, which helps control light pollution and increases efficiency. Fluorescent and standard incandescent light bulbs emit light in all directions.

LED Disadvantages

Cost: Most incandescent light bulbs cost about $1. The same light equivalent in an LED costs from $15 to $50.

Inconvenience: Most LEDs require a 2 to 4 volt DC current. Most households and commercial buildings use 120 volts AC. Converting a household to LEDs requires separate wiring or power conversion units built into the LED lights themselves.

Product availability: Most retail outlets don’t offer LED household lighting to consumers, other than LED night lights. Estimates range from five to 10 years when LEDs might become a replacement for the common light bulb.

Dimming ability: Some LED lights are not dimmable.