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-   -   Why long lasting bulbs go out of service quickly? (http://www.diychatroom.com/f18/why-long-lasting-bulbs-go-out-service-quickly-55866/)

art2670 10-24-2009 11:42 PM

Why long lasting bulbs go out of service quickly?
 
Hello,

First of, I am not an electrician and may not articulate my problem properly. As such, thanks a lot in advance for any responses and comments.

I have been living in a newly constructed home for two years and begin to notice that daylight bulbs in the basement are going out of service way ahead of advertised service life of 8000 hours. These are rather expensive bulbs which I bought originally with an intention to last for a very long time. The lighting structure consist of recessed lighting, i.e. spot lights.

Can anyone provide reasons why bulbs with advertised long life go out of commission after a short period of time in service? I wonder whether I should continue to spend more money on bulbs with long lives, if there is a problem in the wiring system or such......

Thanks,
Art

frenchelectrican 10-25-2009 12:19 AM

I need little more details what on that luminarie circuit

Dimmer ?
Enclosed Luminaire ?
Frequent on / off switching ?

Those above item is the key item may cause the issue

However there are few others issue it may arise

Surge
Viberations { possiblty affect some CFL but super rare }
Substandard bulb { it can happend }
Poor concat with screw in types

Can you tell us what brand bulb you are using now ??

Merci.
Marc

tlj 10-25-2009 12:40 AM

The answer is very simple. As explained by my High School Auto Shop teacher about 1962. Battery manufacturers charge you extra for long life batteries, greater than 5 years, but actually sell an inferior battery to offset the cost of claims. So it is with all types of consumer goods, they really dont make it better, they just charge you more and call it long life.

Here is an other perspective from a GE Engineer at a seminar I once went to. When you buy a lightbulb, you are paying for light output. Over the course of the life of a lightbulb the filament vaporizes and deposits on the glass and darkens the light output. So, over time you are getting less light, which is not what you paid for. So, GE makes their bulbs to last a certain number of hours, when the light output diminishes by some amount they burn out and are replaced. Long life light bulbs merely have a larger filament that last longer, but the darkening process happens anyway. So at the end of their life they may be putting out much less light than what you expected.

I have had long life light bulbs with mixed results. Some in the garage lasted quite a while but when they burned out the glass was very dark. I have had other long life light bulbs that didnt last any longer than standard, and I probably paid too much for them. The bottom line is, unless you are curious like I am, dont waste your time or money on long life lightbulbs.

spark plug 10-25-2009 01:29 PM

Issue of shortened life of "Long-lasting" bulbs.
 
Quote:

Originally Posted by tlj (Post 345090)
The answer is very simple. As explained by my High School Auto Shop teacher about 1962. Battery manufacturers charge you extra for long life batteries, greater than 5 years, but actually sell an inferior battery to offset the cost of claims. So it is with all types of consumer goods, they really dont make it better, they just charge you more and call it long life.

Here is an other perspective from a GE Engineer at a seminar I once went to. When you buy a lightbulb, you are paying for light output. Over the course of the life of a lightbulb the filament vaporizes and deposits on the glass and darkens the light output. So, over time you are getting less light, which is not what you paid for. So, GE makes their bulbs to last a certain number of hours, when the light output diminishes by some amount they burn out and are replaced. Long life light bulbs merely have a larger filament that last longer, but the darkening process happens anyway. So at the end of their life they may be putting out much less light than what you expected.

I have had long life light bulbs with mixed results. Some in the garage lasted quite a while but when they burned out the glass was very dark. I have had other long life light bulbs that didnt last any longer than standard, and I probably paid too much for them. The bottom line is, unless you are curious like I am, dont waste your time or money on long life lightbulbs.

It all depends whether they're Incandescent of Fluorescent. Including CFL. Your diagnosis, as far as the filament continually eroding applies primarily to Incandescent bulbs. In fluorescents, on the other hand there is one factor that is primarily responsible for shortening the life of the bulbs/tubes. That is, repeated switching ON and OFF. Secondary, is the use of (improper) dimmers. (No matter what) :yes::no::drink:Don't Drink and Drive, Ever!!!

kbsparky 10-25-2009 01:34 PM

Basement lights may be the key here. They are subject to the vibrations of the floor above, as folks walk around and such. Depending on the quality of the construction of the floor system, there may be some "bounce" to the floor joists (ceiling joists from below) that can cause premature failure of lights mounted below in the basement.

Yoyizit 10-25-2009 03:14 PM

Quote:

Originally Posted by kbsparky (Post 345224)
Basement lights may be the key here. They are subject to the vibrations of the floor above, as folks walk around and such. Depending on the quality of the construction of the floor system, there may be some "bounce" to the floor joists (ceiling joists from below) that can cause premature failure of lights mounted below in the basement.

Yes and if the pole 'former is right outside they won't last long.

132v into a 120v incand. bulb should give you ~1/4th of rated lifetime.

Piedmont 10-26-2009 11:45 AM

Advertising. The makers of these things know that when they put 8000 hours on the box people are going to pay a dollar or two more for them. They also know when they die after 400 hours only about 3 people out of a million are actually going to file a claim and go through that effort (and I think they have to pay shipping). So... a million extra $'s minus the $100 from people who actual file a claim = a million extra dollars.

Don't waste any money on long lasting bulbs. I used to get long lasting bulbs over my laundry area. Using them 3 hours doing laundry once a week they were dying after 2 months. I used to think it was something with the wiring but ended up getting throw-away bulbs from a different company and they've lasted over a year now. I recommend getting a different brand at least.

tlj 10-26-2009 10:18 PM

Quote:

Originally Posted by spark plug (Post 345221)
It all depends whether they're Incandescent of Fluorescent. Including CFL. Your diagnosis, as far as the filament continually eroding applies primarily to Incandescent bulbs. In fluorescents, on the other hand there is one factor that is primarily responsible for shortening the life of the bulbs/tubes. That is, repeated switching ON and OFF. Secondary, is the use of (improper) dimmers. (No matter what) :yes::no::drink:Don't Drink and Drive, Ever!!!

Yes, you are right, I just provided a personal perspective, and didn't pay much attention to technical detail. Halogen lights may also be a problem if they are on dimmers or are operated at less than their rated voltage, they are designed to operate at a very narrow temperature range for maximum life, or they will darken prematurely and burn out. I have tried them all, and now have LED lights in the ceiling fan in our bedroom. I don't like the light output, but things are interesting when the lights are turned off, they glow just enough to be night lights. This insight help me diagnose and solve a very elusive problem with an opto-coupler circuit, but that is an other story.

As far as florescent lights go, I had to dig into this when upgrading office space. To meet new building codes we are installing occupancy sensors in offices, which do shorted standard T8 bulb life. To mediate this we can install programmed start ballasts in offices with occupancy sensors, but these are still quite expensive. I will continue to watch these bulbs to see how long they really do last compared to other bulbs in the same office. Just curious. When I can get programmed start at a Big Box Store for a good price, I will try them then.

You are right in that many factors may contribute to lamp life. One should probably just stay with standard lights if they would feel some offense that a long life bulb didn't live up to expectations.

AllanJ 10-27-2009 09:10 AM

Traditionally, a long life incandescent lamp is one rated for about 130 volts and originally sold as a standard lamp in (notably rural) areas where overhead lines were too thin, and the first house on the line served by a transformer got around 130 volts in order that the last house get at least 105 volts during reasonably heavy load times of day.

Nowadays (late 20'th century) it has been touted for hard to reach sockets and the disadvantage is that you get fewer lumens per watt.

Not sure whether long life is totally a marketing gimmick in the 21'st century.

They also make (or used to make) "rough service" incandescent lamps that have more supporting wires to hold the filament in a more or less circular shape and can better resist stomping around on the floor above.


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