Friday, December 7, 2012

My Comparative-Lighting Lab, First Result

I am inspired to know that measured lumen output of a light is not correct statement of its ability to provide useful illumination, by this photo:
The photo is posted in the Facebook pages of LED Source, in Wellington, Florida.

Changing lamps at our new corporate headquarters. Look at the comparison between a 13W CFL and a 15W LED Glimpse. Can you see the difference?

A 13W CFL will be rated at about 930 lumens. The 15W Glimpse is rated at 750 lumens.

This is my apparatus attempting similar object illumination. Thinking outdoors despite wet Fall weather, I beam this at my freshly white-painted garage door. 

On the left, a 100 watt incandescent bulb, 1750 lumens. On the right, a T91, 6" Glimpse 14.5 watt plate LED, 750 lumens. Compare brightness as that in each shadow of the divider. I call the 6" Glimpse  brighter by times 1.5, where the manufacturer, LSGC, has been reluctant to claim superiority to more than a 65 watt incandescent. And, I must take care now to not call the 6" Glimpse, the Home Depot abandoned T91. For a time, I must take care to apply both labels.

I think under-rating of brightness is not a defensible safe approach. Those first trying a 6" Glimpse will often find them too bright, wanting them dimmed. Many will prefer a 4" Glimpse, and have not yet been offered the choice. Knowing better, they will demand the choice.

Who ever said a 100 watt incandescent was a standard of brightness? It was only at, or beyond what a fixture could tolerate without damaging wiring insulation, or starting  a fire. A 6" Glimpse is never hot to the touch.

With new standards stated for LED, we can have whatever illumination we need, from fewer fixtures. Those new standards need not carry description of the now-inferior illumination from still-hot compact fluorescent bulbs. How about Brightness Numbers? Say, B6 for 6" Glimpse, B4 for 4" Glimpse. A 100 watt incandescent might be B4, 25 watt B1. Let's get that naming conversation underway.

Perhaps it is the outmoded notion of bulb construction that gives disadvantage. Surely a plate LED will greatly surpass an LED assembly in a bulb, recessed into a can. Some kind of shape factor will affect the relationship of LED power consumption, and its effective illumination. It is only the illumination, the projected brightness in zone of need, that matters. Incandescent and CFL lights can not benefit from shape factors, and are doomed in that way too. Good riddance to foolish contraptions holding bulbs, and surpassing bulbs in cost. 

An LED plate light is a round-the-clock available spot of sunshine on your ceiling or wall. Better light quality, and at night too, than a sun tunnel blocking passage in your attic, maybe leaking heat, and compromising your roof, at large installation cost. Sorry, good folks at Solatube. A little PV array can serve up the daytime electricity for lots of LED plate lights. Let them be, now, strung and more-readily dimmed, as low-voltage DC circuits; said despite concern to not confuse, where DC wiring has not yet been offered except in commercial, RV and boat applications.


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Alexander Coder said...

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