I've never really given much thought to this until recently. Why would I want to put multiple bulbs into a single fixture?

Every bulbs burns at a specific brightness. Putting more bulbs next to each other won't make the light brighter. Or will it?

So what does it actually do? Obviously, it will spread out light at a larger area, but how much are you actually achieving if the bulbs are so close together as they are with this fixture?

Light fixture for 3 bulbs

The question came up because I'm equipping multiple rooms with LIFX bulbs. When I spend that kind of money, I'd like to know that I'm actually achieving something by putting multiple bulbs right next to each other.

  • Putting more bulbs next to each other won't make the light brighter. Or will it? - It will. May 7 '17 at 16:35
  • @A.I.Breveleri, why don't you post this as an answer, along with an explanation of why (total lumens, etc.)? May 7 '17 at 16:39
  • 3
    Harper got to it first. Took me too long to do the research because it is too dark in my library. Two of the three bulbs are burned out. May 7 '17 at 16:50
  • Another design point is that you're not left in the dark when the first (or second) bulb burns out. Hopefully the lower level of light will make you realize before the last burns out.
    – Tyson
    May 7 '17 at 22:45

We use artificial light to light up things. The brightness of a thing depends on how many photons are falling on it. Doubling the number of bulbs actually does double the number of photons. That makes the thing visibly brighter.

One basic method of dimming a room is to have 2 switches, each of which controls some lights.

More bulbs will not throw the light any farther. What will happen, however, is that faraway things will get more light with more bulbs. For instance with a single bulb, it might get 5 lux... with 4 bulbs it will get 20 lux and thus be more visible.

  • 6
    Also, at least when using ordinary incandescent bulbs, it sometimes makes sense to use multiple bulbs in fixtures that are difficult to access. The light fixture at the top of my stairwell was designed to use 8 small bulbs; when one or two have burned out I still have enough light and do not need to get up there to replace until most have burned out. May 7 '17 at 16:56

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