Incandescent Lights – Still Using 150-Year-Old Tech

by Erik North on January 24, 2012

Incandescent Lights - Still Using 150-Year-Old Tech


This is a post that may not be needed as most everyone has read by the light of an incandescent bulb their whole lives. It’s a technology that I said in the post title dates back 150 years, but it’s origins are closer to 200 years back. For most of America, electric lighting made its national debut at the 1893 Chicago World’s Fair, the Columbian Exposition. This was probably the largest single display of electrical lighting to date.

Incandescent lights have a long history, but it’s also a very well known one. Why rehash information about such a well-trod subject? Because we’re on the cusp of the first paradigm shift in electric lighting since Edison and Tesla’s child was introduced to the U.S. public. Knowing about the existing technology helps us compare it to those possible successors in residential lighting.

What is an Incandescent Light Bulb?

Incandescence is the visible light emitted from a hot material. Incandescence is specifically the visible light. The heated substance will also radiate infrared (and a whole host of other radiations along the spectrum).

An incandescent light bulb heats a wire filament, usually tungsten, to a high temperature until it glows, emitting visible light. The glass bulb is either evacuated (a vacuum) or filled with nitrogen.

Incandescent Bulbs – Advantages

Price: Right off the bat, let’s hit the big one. On a per unit basis, incandescent light bulbs are the least expensive form of residential lighting. A bulb for residential use costs about $0.50. CFLs may be cheap on a wattage consumption basis, but the up front cost of incandescent bulbs is the least expensive per lumen (a measure of perceived light output).

Size: On a residential scale, incandescent light bulbs come in about every conceivable size and shape. If there is a task around the house that needs lighting, there is some variant of incandescent bulb to light it.

Light Quality: The quality of the light produced by incandescent bulbs is the industry standard. A combination of being a pleasant amber-white and being the shade of light to which everyone is accustomed draws a contrast with the harsh white of CFLs.

Color: Incandescent light bulbs can be made any color just by changing the tint of the glass bulb.

On/Off Time: The on/off time on an incandescent light bulb is almost instant. Just as much time as the electricity needs to heat the tungsten filament (literally microseconds).

Dimming: Incandescent light bulbs are fully dimmable. The brightness of the light is a function of how much electricity is running through the filament. Changing the electricity changes the light.

Frequently Turning On/Off: Turning an incandescent light bulb on and off frequently does not affect an incandescent as adversely as a CFL.

Light Direction (the Good): Incandescent bulbs produce omni-directional light, making them ideal for general living spaces where you want good light coverage.

Chemicals: Incandescent light bulbs have the nitrogen gas, tungsten filament, glass bulb and base. There is no analogous issue to the mercury used in CFLs.

Incandescent Bulbs – Disadvantages

Efficiency: An obvious one … of all major commonly used residential lights, incandescent bulbs produce the least amount of light per watt. There have been efforts to improve efficiency that have met with middling success.

Temperature: Incandescent light bulbs get hot. Really really hot. The filament itself operates around 3,000 – 5,000 F (just an insane temperature when you think about it). This varies based on the bulb type and electrical current. In any case, easily hot enough to burn flammable anything.

Bulb Failure: At such ridiculous temperatures, the tungsten filament gradual erodes (or more accurately, evaporates). Doesn’t that bother anyone else that metal is evaporating? Anyway, once the filament breaks, the light dies instantly.

Lifetime: The lifetime of an incandescent bulb is all over the map, varying based on all those factors we’ve discussed – size, shape, electric current. The most common range is 750 – 1500 hours, with 2,000 hours as an absolute outside.

Durability: Durable they are not. Great, I’m speaking like Yoda now. The glass bulb encasement is very fragile.

Light Direction (The Bad): Single point applications like flashlights require incorporating a mirrored reflector to direct light. This is why LEDs are much more common as bulbs for flashlights today.

Incandescent bulbs have a number of qualities like their warm, amber glow and low price that we’ve come to measure all residential lighting. Their enormous shortcomings in electric use and longevity mean that as more efficient options improve light quality and cost, they will likely overtake incandescent bulbs (and CFLs) in the market.

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