Do Light Bulbs Have a Shelf Life?
With light bulb technology changing more in the past ten years than in the entire past century, durability becomes a point of comparison. Do light bulbs have a shelf life? Yes. After all, traditional Incandescent (INC) bulbs only cost a couple dollars, while Compact Fluorescent Lights (CFL's) and LED's (Light Emitting Diodes) can cost more initially, sometimes as much as ten times as much, spreading their savings over a span of years of use. As governments around the world advocate for transition away from incandescent bulbs, some people consider stockpiling their beloved warmly-lit Edison bulbs for as long as they remain on the market.
Just how do these three types of bulb compare? This article will evaluate them according to:
- Shelf life
- Initial purchase costs
- Electric costs
- Energy costs
- Rated usage lifetime comparison
- Watts
- Replacement
Light Bulb Life
Most contemporary light bulb technology will have a considerably long light bulb life, perhaps even indefinite. Certainly each bulb technology can last for decades in storage. When properly stored away from moisture or physical abuse, and whether new or having some runtime, nothing can really change with their basic technology in extended periods of inactivity. But let's examine them a bit closer
INC Light Bulbs
These Edison-style bulbs can go bad if:
- The glass bulb is broken or improperly sealed; gas can leak out.
- Light is blocked because the interior of the bulb is coated with a thick layer of tungsten from the filament. Tungsten filaments can only do this under the heat of direct use, and not in storage.
- The filament breaks do to shock or overuse.
Oxidation, or rust presents the only other risk for these bulbs, and only then if it breaks the vacuum seal on the glass envelope, or corrodes the contact point. Simply storing them in plastic bags, as well as shock-absorbent packaging, will prevent such occurrences.
Some people believe that glass "flows" over a long period of time, because it is an amorphous solid. They cite old window panes as examples, which appear thicker on the bottoms than at the tops. However, this phenomenon does not affect bulbs at all, and indeed, not even windows. Old glass manufacturing techniques created uneven panes; glaziers merely installed the thicker side down, for more support.
According to GE, the shelf life of an incandescent bulb is forever.
CFL Light Bulbs
These bulbs will meet the same conditions as incandescents, with indefinite shelf lives, provided they are properly stored. Broken CFL's, however, require hazardous waste cleanup, as they contain mercury, which is a cumulative poison that can lead to developmental problems. Proper disposal is a more pressing concern than storage with these bulbs.
LED Light Bulbs
These lights are made largely of plastic; as such, they are waterproof , chemically stable and nonreactive.
While also subject to oxidation from excess moisture, if stored properly an LED light's shelf life should be for decades, centuries, or even millennia. While the epoxy dome and phosphor coating may degrade if exposed to higher temperatures and UV radiation, under normal storage conditions these issues will likely not present themselves.
Based on this criteria alone, you can stock up on any bulb of choice, knowing it will be able to perform when you need it.
The following research estimates come from Mapawatt.com, an energy and water conservation website, and cover an operating period of ten (10) years:
- Initial Costs: INC: $.75 CFL: $1.46 LED: $40
- Electric Cost: INC: $83.22 CFL: 20.44 LED: $8.76
- Energy Costs (kWh): INC: 832.2 CFL: 204.4 LED: 87.6
- Rated Usage Lifetime (hours): INC: 1500 CFL: 10,000 LED: 50,000
- Watts: INC: 57 CFL: 14 LED: 6
- Replacement bulbs: INC: 10 CFL: 2 LED: 1
- TOTAL COST: INC: $90.72 CFL: $23.36 LED: $48.76
Finally, other factors merit consideration for comparison. Environmental costs, costs of replacing existing fixtures, inability of some existing fixtures to house larger CFL bulbs, health risks associated with broken CFL bulbs and mercury, and addition of fixtures to compensate for CFL and LED's relative lesser brightness.
It also pays to purchase bulbs under full warranty to offset the cost of defects, which some CFL owners report after only a short operating time. As most of these bulbs are produced overseas, quality control can sometimes be an issue (employment & economic costs?). Even under warranty, replacements require time, fuel, production and shipping costs, which should also be factored in to an increasingly complex equation.
The warmth (or heat energy loss) of INC's, replaced by CFL's and LED's affect heating costs, which would increase using the cooler lighting of CFL and LED. While some denote this as waste, that really applies only to warmer months. CFL's may be affected by frequent usage, which effectively shortens their lifetimes. Therefore CFL's may be more suited to areas where lights are activated for longer periods. LED's do not suffer the same limitations under constant use. Because LED's don't produce infrared, they don't emit any noticeable heat. INC's work best where lights endure active use for shorter periods, such as in bathrooms, bedrooms, and around dressing room mirrors. One final cost suggests that as technology and markets develop, the price of LED's will in fact come down, making that initial investment a little harder to recoup by comparison.
While bulbs offer various qualities of light, technical innovation generates more choices of light qualities among each of the bulb technologies.
The take home point suggests that a key difference lies in whether you are replacing bulbs for existing fixtures, or planning lighting for a new home. If the latter, perhaps investing in LED lighting presents the soundest option for longterm future needs, say, over the course of thirty years Short term future should see a greater widespread adoption of CFL's. But INC's have one distinct advantage over the others: with tried-and-true technology, they have withstood the test of time - and fill an irreplaceable void in the homes, cultural landmarks, and hearts of many.
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