Incandescent Bulb "Wear Out"

Page 1 of 3  
I hadn't thought much about this before but today I started wondering what percentage of light output is typically lost as a large (100-250 watt) incandescent bulb ages, before it's filament finally fails.
It seems to me that the noticeable deposits on the inside of the glass bulb must block some light, and as the filament boils off some of it's tungsten its resistance must increase, so the power dissipated in it will drop, reducing the light output.
Or, maybe it's just my aging eyes. <G>
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
jeff_wisnia <jwisnia18DUMPTHIS comcast.net> wrote:

Not trying to hijack your thread, but... That's another advantage to compact fluorescent. I've almost forgotten what it's like to change a lightbulb.
How many people does it take to change a compact fluorescent light bulb? None!
--










>
> It seems to me that the noticeable deposits on the inside of the
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
1) Then, don't.
2) I've changed a bunch of them.
Christopher A. Young Learn more about Jesus www.lds.org .
Not trying to hijack your thread, but...
How many people does it take to change a compact fluorescent light bulb? None!
--










>
> It seems to me that the noticeable deposits on the inside of the
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
as to the original question if the filament doesnt fail light output will be cut dramatically.
I had a 300 watt indandescent bulb in a living room light for grandma, on a dimmer so she could set the light output she needed, more for reading etc.
Since the lamp rarely ran at full brightness the filament nearly never burned out but the inside of the glass would turn nearly all black, and I would replace the bulb....
Incidently newer name brand CFs last nearly forever, the first dollar store type failed fast.
CFs are well worth their cost, and are saving me big bucks on electric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 2/4/2013 6:30 PM, bob haller wrote:

Thinning filament might get hotter and actually burn brighter but at some point fails because of higher heat essentially melting, I would guess. Grandma's never sees these high temps and bulb lasts longer.
I don't like cfl's in places where they are turned on and off frequently like a bathroom. I've noticed these tend to fail faster.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Dont leave us in suspense. Which brands last forever? I've used the cheap dollar store ones, as well as Sylvania and GE. None seem to last long.
I dont use them in the bathroom either, turning them on and off definately does shorten their life and when I enter the bathroom in a rush, I may need FULL brightness so I dont miss the toilet :)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The CFLs marked "Energy Star" last the longest in my experience probably because they have to be life tested and the data submitted to receive E* listing. Lamps that I've tracked last 10 years or longer in residential service. But, starting a fluorescent lamp (of any kind) does shorten the lamp life.
Tomsic
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Besides the shorter lifetime due to multiple starts, placing them in a socket-up position will overheat the electronics in the base drastically shortening lifetimes.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 4 Feb 2013 19:33:43 -0800 (PST), " snipped-for-privacy@sbcglobal.net"

VAST majority of lamps are socket up in actual usage. Should be designed for that use.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 04 Feb 2013 22:53:57 -0500, snipped-for-privacy@snyder.on.ca wrote:

Exactly true. Except for the ones that sit in a horizontal position such as typical bedroom fixtures, nearly every bulb in my house and out buildings sit with the base up. Table lamps and a few outdoor fixtures are the only exception. I dont fully understand why this would be true anyhow. The spiral glass part dont get real hot, it's the electronics in the base that generate heat. In some ways, you'd think that heat from the base would dissipate into the fixture.
Now the sealed globes over some lights could hold in the heat, and that makes more sense.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I still have two CFLs that Con Ed gave me probably 20 years ago. In their current position they probably get turned on about once a day for 5-30 minutes. But most of the others from back then are gone.
I had a CFL with a warranty and when I filled out the info on their website (it took two tries before they responded) they mailed me a $10 Home Depot gift card- I didn't have to send in the bulb.
My experience is that the dollar store ones don't last but the better ones mostly do, generally around 5-7 years is my best guess. And since they're no longer expensive they do save money.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Besides the shorter lifetime due to multiple starts, placing them in a socket-up position will overheat the electronics in the base drastically shortening lifetimes.
Yes, I agee. And putting CFLs in small enclosing fixtures, no matter what the socket position, can do the same thing. CFLs made well and operated base down in fixtures with good air circulation will give maximum life -- probably beyond the usual 10,000 hour ratings.
Tomsic
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That all sounds simple and makes sense, but how the hell do you install a ceiling light base down? You'd have to use all table lamps, or put light fixtures on the floor. These companies know how light bulbs are installed (I hope). They should be designed to operate base up. Maybe there could be an after-market heat shield or something..... Although they should make them FOR base-up uses, since that's how at least 90% of them are used. The only fixtures in my house that are not base-up are two bedroom lights - horizontal bulbs and two bathroom wall fixtures that are base-down, but I dont use CFL in the bathroom cuz of the many on-off cycles. (table lamps and trouble lights not included).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 2/5/2013 4:20 PM, snipped-for-privacy@home.com wrote:

Depends on the fixture.
http://www.lampsplus.com/products/chandeliers /
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:
<snip>

It will likely get sorted out as we move slowly away from screw-in bulbs and existing sockets and begin using more dedicated fluorescent and LED fixtures where the fixture is engineered to take account of the thermal needs of the light source. Such fixtures now, for example, typically separate the LED and driver circuitry and build in heat sinks and other ways to keep the temperatures under control. Few recognize how difficult it is to design this new generation of screw-in electronic bulbs. The bulb has to be small, even tiny, and then the socket and most of the existing lighting fixtures are designed to only make the fixture safe at elevated temperatures, not to keep the bulb itself near room temperatures. Fans, metal heat sinks and liquid-filled bulbs are all being tried. The new GE LED bulb, designed to replace a standard 100 watt, even has electronic "lungs". I don't hold out much hope for existing fixtures that operate CFL and LED base up. They'll always operate the lamp circuitry hotter than base down; but as the lamps themselves become more efficient, lamp watts (and heat) will be reduced for the same amount of light and that will help. Or, maybe we'll begin to see adapters and kits that will change the bulb orientation or with clever ways to handle the heat. That's whats happening with the LED downlight conversion kits. They have large heat sinks with some disguised as decorative trim rings.
Tomsic
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

All energy star checks is power consumption. And they don't check every one. The advantage is cheapassed manufacturers won't pay for the certification. The downside is the chinese will put any label on any turd and pass it off as "energy star" - and you don't know the difference.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 2/4/2013 9:52 PM, snipped-for-privacy@snyder.on.ca wrote:

http://en.wikipedia.org/wiki/Energy_star#Lighting "The Energy Star is awarded to only certain bulbs that meet strict efficiency, quality, and lifetime criteria."
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Still doesn't addres the "C-Factor" - and they do not check to make sure every bulb meets the spec the first one met.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 2/5/2013 12:01 PM, snipped-for-privacy@snyder.on.ca wrote:

>

Whatever that is.
As wikipedia makes clear, Energy Star is about more than "power consumption".
The post you responded to said Energy Star included life testing. Wikipedia says Energy Star includes "lifetime criteria".

There should be a test for every bulb? Not in the real world. UL tests representative samples at the start and has periodic checks, which may not include testing the product.
Every bulb should be tested for "lifetime criteria"?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

The "china factor"

No, but their should be spot checks. I've bought numerous products out of china - first one you get excedes all specs -a bit farther along they JUST meet specs, and then after they have you comitted, the crap starts rolling in. Nowhere CLOSE to spec.
In most cases, where the product design did actually meat all the requirements for energy star rating, rather than just getting a counterfiet label attatched, the product sold and put on the shelves a year or so later is a totally different product.
That is the "C-Factor" ( AKA "China Syndrome")
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.