Do incandescent get dimmer with age?

[Chris Jones]

From what I'm reading they do, if they last long enough to. Most burn out before they dim much. What gets me to wondering is I have one of those light bars over the bathroom sink with 4 globe type incandescent bulbs. They've been there for many many years. Perhaps 10+. they never seem to burn out. Still I've been finding the bathroom dim and wondered if it was just me. I just bought 2 compact florescent bulbs that actually look like incandescent globe bulbs just to try. I got 60w equivalents (13 watt). I hate the time it takes them to warm up but boy are they bright when they do. The old bulbs I took out were all 120 volt but one was 60 watts, another 40, another 25 and the last was unmarked. Funny when they were in the fixture I couldn't see any difference in the light output at all. And none of them were near as bright as the new compact florescent bulbs. I guess I'll just pick two of the incandescent ones to go back in with the two florescent bulbs. They will at least provide that immediate light when the switch is first turned on. I hate to throw away a bulb that still lights but I'm not sure old incandescent globe bulbs are worth keeping. My guess is incandescent globe bulbs last long enough to dim while regular incandescent bulbs burn out before they dim. Any thoughts?

 

[CENTAUR]

There are different kinds of flourescents.The cheaper sperial type do not seem to last as long if you turn them off and on like I do with the regular bulbs .I changed over to all when they came on the market to save and I did for a short while.All went BAD within a short time for all three brands I bought.However the three high priced ones which come on slow still work fine but they are big and heavey and do not fit in many places.I have went back to the old type and now I now I do not have to replace near as often.I now wonder if I saved $ in the end. CENTAUR

 

[Gun Guy with brains]

Dirt builds up on the bulbs and it seems to get dimmer.
Also, the glass on the bulbs I think burns and gets darker too a little.

 

[Gun Guy with brains]

Dirt builds up on the bulbs and it seems to get dimmer.
Also, the glass on the bulbs I think burns and gets darker too a little.

 

[Anonymous-0]

The simple answer would be no but the truth is that yes incandescent light bulbs do get a little dimmer with age. One from the glass getting a little smoked up inside and also dust and pollution collecting on the outside. But the main reason is that the filament inside gets real hot. The higher the wattage the hotter the filament. Over time the resistance of the filament tends to increase and the filament does not get as hot and the light drops. That is why most bulbs are not made to last long. I am glad you got more light output with your compact fluorescents because I have not found one case in my use where the compacts produced the most light that was pleasing to my eye. Also most of my fixtures will not take the larger compacts. I will keep looking for that magic light that produces a lot of light and is easy on the amps.

 

[Chris Jones]

Yea, not really looking at it as money saving, cause I agree compact fluorescents aren't money savers in common incandescent use. If it's a lamp that's on say 6:00pm till 11:00pm each day but otherwise never turned on you might come out ahead over 3 years. Compact fluorescents cost too much given I only pay 25 cent for an incandescent and they don't last nearly as long as claimed. I've done the math in a spreadsheet taking into account hours of use per day, cost per kilowatt hr I pay, cost of bulb and life the bulb mfg says it's good for. This shows break even is out there a ways. Now take into account fuzzy things like I don't believe they actually last that long and the cost of fluorescents is upfront and they aren't worth putting up with the poor color and time to come up to full brightness for many applications--to me anyway. But I do now have 7 in use.

 

[Anonymous-0]

I think they do get dimmer as time goes on.
The filament part evaporates and condenses on the bulb inside which would help to block some light.
Ever notice the bulb start to get black near the base of the glass start to get black.
Even the long tube of the fluorescent, on the ends where the incandescent heaters are.

 

[Sunspot]

i've tried a few of the globe type fluorescent replacements and they don't seen to be worth the trouble. I do use the 4' shop lights. The best ones I've found so far have a 5,000 kelvin with a CRI (color rendering index) of 98. A nice pure color. I also have the same type in my kitchen but I DO hate the buzz of the transformer in the house.