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Light Tube - add a Wye?


John Kogel

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If we cut a hole in the side of a light tube, which connects a rooftop lens to the ceiling drywall, and run a second tube from that hole thru the ceiling, will we get more light in the room?

No. You'll get less.

True, but perhaps a *better* light. Those dang tube-type skylights are so bright that I'd rather have two dimmer ones. (Can't tell you how many times I tried to turn them off at a light switch when leaving a room.)

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If we cut a hole in the side of a light tube, which connects a rooftop lens to the ceiling drywall, and run a second tube from that hole thru the ceiling, will we get more light in the room?

No. You'll get less.

True, but perhaps a *better* light. Those dang tube-type skylights are so bright that I'd rather have two dimmer ones. (Can't tell you how many times I tried to turn them off at a light switch when leaving a room.)

I suppose they are brighter where you live, catching a more direct beam from the sun.

I was wondering if there is only a finite amount of light entering at the roof lens, True, you say,

then splitting the light with reflectors, or spreading the light over a larger area of the ceiling does not result in more light. Correct?

Some of that light could be directed into an area that is now dark. The tube in the attic can be made more reflective with mirrored surfaces. What y'all are saying is that mirrors will not increase the light. I suggest that mirrors will reduce losses into the attic.

There is one version that has an opaque tube which lights up that whole area of the attic.

Light tube joke - "It comes on by itself every morning, and you can't turn it off".

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If this light relies on reflection then it is like a moon. If your sky had two moons in it instead of one, would not there be more light delivery?

Yes, in Northern latitudes in the winter, the sunlight hits the side of the tube, and then is reflected down to the lens in the ceiling. If you look up into the tube, you can see that the side of the tube opposite the sun is brighter and that bright area rotates as the earth turns the house away from the sun.

Sure we could install another light tube for twice the light.

But my question is can we catch more light from just the one roof tube by dividing it. Y'all say no.

Can we make the distribution more efficient? Yes, we could do that, reduce the losses with better reflection. Then suppose we reflect that salvaged light toward another lens in the ceiling.

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Yes, Marc, Kurt straightened me right out on my terms.

So if light can be quantified by breaking it into a number of particles or a number of wave segments, how many get bounced by reflective surfaces to the end of the tube. How many get lost along the way, and if they are divided by a fork in their road, do their numbers stay the same or do they get halved at the fork?

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I want to see this conundrum expressed in a mathematical equation.

1X divided by 2 = 1/2X

Study the Fresnal equations and get back to me. The answer is there, just beyond my grasp. [:-graduat

The tinfoil helmet isn't helping.

Jim B, you have seen the light. My quest is to retrieve some of the diffused light that would otherwise be lost, reflected back or absorbed. Thus there will be more light.

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