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120v or 130v incandescent bulbs

Posted by joelbuckley (My Page) on
Sun, Dec 27, 09 at 19:22

I've heard that 130v will tend to last longer but will produce less light output. One source says 130v bulbs are only 70-80% as bright as 120v bulbs. I can believe this, but the numbers on the manufacturers' spec sheets don't tell the same story. A Phillips 130v 65W BR30 reflector flood (248849) is rated at 635 lumens. A similar 120v bulb (248765) is rated at 640 lumens. Nearly the same brightness. What gives?

Here's my theory: The 130v bulb makes 635 lumens at 130v, and the 120v makes 640 lumens at 120v. Each bulb consumes 65 watts of power at its rated voltage. The trouble is, the specs don't tell you what the 130v bulb looks like at 120v. According to hearsay, it's 20-30% dimmer. But... I would expect it to consume less power too. It's not using 65 watts to produce 70-80% as much light... it's using, say, 55 watts. Sure, it would be somewhat less efficient than the 120v bulb in terms of lumens/watt, but not that much less efficient. Right?

I hate light bulbs. All light bulbs.


Follow-Up Postings:

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RE: 120v or 130v incandescent bulbs

If all you can get is 9.8 lumens per watt from a BR30 lamp you should be as concerned about wasting your money on electricity as on lamp life. Lamp life is only an average from tests and is often not reliable. For a 20 to 30% increase in efficacy try PAR lamps and if you want lower power cost and longer lamp life try low voltage fixtures on dimmers.


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RE: 120v or 130v incandescent bulbs

Unless you have lots of them in one area the where you might notice the total area lumens, output will not be noticeable but 130v is slightly less bright.

Lamp Lumen rating is rated when operated at the nominal voltage specified.

Theoretically 130v lamp operating at 120v is 120v/130v = 92% effecienct... so a 635 lumen at 130 in theory would be in the neighborhood of 635 x .92 = 584 lumens.. but this is not true.. lumen output will be better than that as the design voltage has actually a variable and is not exactly steady state 130v design & the nature of the beast.
Design voltage might not be specified as such but is nominal... another words be something on the order of 126v to 132v actual design.

I forget the numbers but 130v bulb used in a 120 application, the average lamp life hour rating is then maybe 20 to 30% increased, and really with un noticeable to most eyeballs, less bright. Unless of course theres lots of them in one area.

I'm rambling.. sorry. Unless the total foot candles for the area derived from those lamps is very low or very high.. I seriously doube you will notice less lumens.


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RE: 120v or 130v incandescent bulbs

watt for watt,,, it uses the rated energy. 130v filiment has more resistance, or less,, im having brain fade.. so the filiment at rated design voltage is the same pretty color.


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RE: 120v or 130v incandescent bulbs

Please understand that when manufacturers rate their lamps , it is at the stated voltage.
A 60w-130v lamp will give off 635 lumens when it is operated at 130v.
If your run a 130v lamp on your 115-120V circuit, it will produce 20-30% less light output.
You were given the right info in the first place.
By using 130v lamps., you will achieve longer lamp life , but at the expense of using more energy to attain the same light output.


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