HISTORY OF LIGHTING
“In principle, the technology is simple: electrons and holes are injected into a forward-biased semiconductor p-n junction; they recombine creating photons; the resulting photons are extracted from the chip; then the photons are either mixed with different-color photons from other LEDs, or are energy down-converted into a distribution of colors using phosphors or other down-conversion materials, with the colors chosen so as to create the appearance of white.” -From Sandia National Lab website on LED lighting(if this is “simple” we wonder what complex looks like)
“There are two kinds of light–the glow that illuminates, and the glare that obscures.” - James Thurber
From prehistoric times we have burned things to make light starting with, probably, whole dried fish. This, no doubt, led to the expression, give a man a fish and he will paint pictures in a cave, teach a man to fish and he will burn down his hovel.
As technology progressed we’ve burned animal fat, olive or other vegetable oils, whale oil, and kerosene. All of these produce very little light, quite a lot of heat, smoke, and soot and are often very smelly and quite dangerous (e.g., The Chicago Fire).
For example, the lamp in Van Gogh’s The Potato Eaters was invented in 1783 and “…the light was minimal and it smoked badly but it was better than candles, fat lamps or nothing” (from www.antiquelamps.net).
In 1879, Thomas Edison perfected the incandescent light bulb, followed practically immediately by the invention of the first electric bill.
Edison would recognize today’s incandescent light as it has changed very little since 1879. Incandescent lights produce a lot of heat and a little bit of light. About 95% of the energy used in today’s incandescent lights is wasted as heat – only 5% of the energy actually makes light.
Invented in 1927, fluorescent lights are more efficient, with 20% of the energy used going into making light and 80% going into heat. While much more efficient than incandescent lights, fluorescent lighting used to be harsh with a strong bluish tint to the light. Additionally, they used to have a fairly large amount of mercury in them. Mercury is a strong neurotoxin.
Recent Compact Fluorescent Lights (CFL) have made much progress in improved color and quality of light. CFLs have much less mercury in them than fluorescent lighting of even 10 years ago. Not all CFLs work well with dimmers or when cold. CFLs last 7 to 10 times as long as regular incandescent lights.
LED (Light Emitting Diodes)
The Next West home uses the latest and best lighting technology we’ve come up with so far – Light Emitting Diodes (LED) or solid-state lighting. LEDs are very energy efficient, can produce excellent quality and color of light, work with most dimmers, work when cold, and contain no toxic mercury. LEDs last 5 times as long as CFLs (50,000 hours). We estimate that the LEDs used in Next West have 40% of their energy use going into making light and 60% turning into heat.
Like any new technology, the best LEDs are expensive to purchase, but prices are coming down very quickly. And when combined with energy savings and lasting more than 25 years in typical home use, LEDs are a good investment even at today’s price tag.