Understanding Life Hours, Part 3: How to Extend the Life of Your Bulbs

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The third and final part in a series about life hours and how you can use this spec to inform your purchase and maximize the life of your bulbs.

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If you’re a lighting nerd like most of us at 1000Bulbs.com, you’ve likely heard of the 110-year-old Centennial Bulb in Livermore, California. If (more likely) you’re not a lighting nerd, here’s the brief rundown: The Centennial Bulb was installed in a firehouse over 110 years ago and still hasn’t burned out. It’s not known exactly how it has lasted so long, but there are a few good clues: One, it has only rarely been moved; two, it has been switched off only a handful of times, and three, it is operated at very low power.

The Centennial Bulb in Livermore, California (Wikimedia Commons)

The two previous articles in this series explained how manufacturers determine life hours and how life hours and warranties are two different things. This third and final article in the series explains how you can make your light bulbs last longer. We can’t guarantee they’ll last 110 years (in fact, we can almost guarantee they won’t), but by following a few tips you can easily double or triple the life of your bulb. One caveat, however, because not all light bulbs use the same technology, these tips do not apply to all bulbs.

Don’t move it! Light bulbs get hot. Really hot. And when metal (which makes up a bulb’s filament) gets hot, it gets brittle. The more you handle a bulb with a brittle filament, the more vibration you subject it to, making the filament much more likely to snap. This doesn’t apply only to handling the bulb; it also applies to placement. Any bulb installed in a place that moves also moves. The swish of a ceiling fan or the slam of a refrigerator door, while barely heard by you, is a light bulb’s death knell. It’s for this reason that you may have seen special bulbs with reinforced filaments marketed as “ceiling fan bulbs” and “appliance bulbs.” As you might have picked up, this rule only applies to bulbs with filaments, like incandescent and halogen bulbs.

Leave it on! This may sound contradictory to common sense, but it’s not. Every time you flip a switch, you are blasting your light bulb with power. That poor little filament is forced to go from room temperature to 5000° F in a fraction of a second! You do that too many times, and the filament will literally crack under the pressure. This also goes for ballasted bulbs like linear fluorescents, CFLs, and HID lamps. In the case of an instant start fluorescent ballast, you’re hitting the fluorescent tube cathodes with 600 volts every time you flip the switch. After so many power cycles, the lamp will fail. Keep in mind, however, that while this trick will prolong the life of your bulb, it could also increase your electricity usage.

Operate it at low power. This may be the real secret to the Centennial Bulb’s longevity. Less power means less heat, which translates to less stress on a bulb filament. If you live in the United States, your house is operating on ~110V, so if you buy a bulb rated for 130V, you’ll be hitting the bulb with 15% less power than it is designed to handle  (130V – 15% = 110.5V). You can stretch this principle even further with a dimmer switch. When you dim a bulb, you are lowering the voltage delivered to the bulb filament, putting it under less stress. This also applies to fluorescent technology, but in a slightly different way: Unlike an instant start ballast, a programmed start ballast supplies a much lower starting voltage and heat to the lamp.  If you switch to this type of ballast, you could extend the life of your fluorescent bulbs by over 30%.

Finally, remember that the aim of extending bulb life, in most cases, is to save money. Is it really worth it to make that incandescent bulb last forever by dimming it and leaving it on for longer periods? In many cases, it’s better to switch to a more efficient CFL or LED. But if you’re a die-hard incandescent fan, or want to recreate your own Centennial Bulb, these tips will come in handy.

Understanding Life Hours, Part 2: Life Hours vs. Warranties

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Part 2 in a series about life hours and how you can use this spec to inform your purchase and maximize the life of your bulbs.

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In the previous article, we discussed how manufacturers determine life hours differently for incandescents, fluorescents, HID lamps, and LEDs. Switching to something less technical, this article will give you information that is much more practical, namely, how to choose the right light bulb for your application.

Life hour ratings are often confused with warranties, but unlike a warranty, a life hour rating is not a guarantee of the life of the bulb. If your light bulb is rated for 1,500 hours and has a warranty of one year, you’ll be hard pressed to get the manufacturer to reimburse you the cost of the bulb after one year and a day, even if you only used the bulb 1,499 hours. Likewise, the manufacturer would be likely to reimburse you if your bulb failed one day short of a year but you used the bulb 1,501 hours. (On a side note, if you set a stopwatch every time you screw in a light bulb, you need to find a new hobby.)

Will your warranty cover this?

So when you go to buy a light bulb, should you just ignore the life hour rating and look for the longest warranty? That depends on your application. If you’re a homeowner looking to get your full return on some expensive new LED bulbs, you’d be wise to look for an ironclad warranty. But if you’re outfitting an auditorium with 50 foot ceilings, you’d be better off selecting bulbs with the longest life hours. Why? A warranty isn’t much consolation when you still have to climb 50 feet to change a bulb.

Several major lighting manufacturers don’t even offer warranties, and if they do, they tend to make the warranty documentation difficult to find and contingent on more variables than most people care to read. Sylvania’s Quick60+ Warranty, for example is a system warranty, meaning it only applies if you are using both Sylvania lamps AND ballasts in your application. If you’re using Advance ballasts with your Sylvania lamps, then sorry, you’re out of luck!

The other two of the “big three,” GE and Philips also tend to be stingy with their warranties. However, a lack of a warranty doesn’t mean a low-quality bulb. In fact, if you’re into the big brands, just the opposite could be argued. You’ll remember from the last article in this series that life hours represent roughly the amount of time it took one half of a test batch of bulbs to burn out. The other half hadn’t yet burned out. Think about your application, how often you’re going to use the bulb, and how likely you are to hold on to your receipt. You might find yourself less concerned with warranties than you thought.

In the next and final installment of this series, we’ll tackle the fine art of making your bulbs last longer, sometimes longer than either warranty or life hours. A hint: It’s not really an art at all.

Understanding Life Hours, Part 1: How Are Life Hours Determined?

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Will this bulb really last 1,500 hours?

Part 1 in a series about life hours and how you can use this spec to inform your purchase and maximize the life of your bulbs.

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The term “life hours” sounds simple but is one of the most misunderstood of all lighting terms. A life hour rating isn’t a warranty or guarantee of a light bulb’s life, so the life hour rating you see on a bulb’s packaging isn’t necessarily how long the bulb will last in your fixture.

A manufacturer’s projection of life hours has to take into account many variants including the calibration of manufacturing equipment, temperature fluctuations, and material quality, to name just a few. By using a big enough test sample, manufacturers hope to account for any manufacturing inconsistencies, making their rating as accurate as possible.

Manufacturers determine life hours for filament lamps, fluorescent tubes, HID lamps, and LED bulbs all in slightly different ways. Here’s the rundown:

Filament Lamps (Incandescent and Halogen)

• Manufacturers test a group of sample lamps by burning them continuously.
• The point at which 50% of the lamps fail is the life hour rating.

Fluorescent Lamps (Linear, U-Bend, Plug-In)

• Manufacturers test a group of sample lamps by burning them for 3-hour intervals.
• The point at which 50% of the lamps fail is the life hour rating.

HID Lamps (Metal Halide, HPS, Mercury Vapor)

• Manufacturers test a group of sample lamps by burning them for 10-hour intervals.
• The point at which the lamps meet 40% of their original lumen output is the life hour rating.

LED Lamps

• Manufacturers test a group of sample lamps by burning them continuously. Like HID lamps, LEDs aren’t allowed to burn out.
• The point at which the lamps meet 70% of their original lumen output is the life hour rating.

In the next part of this series, we’ll show how you can use this information to inform your light bulb purchase.

A Simple Explanation of the Light Bulb Ban

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