Monday, June 29, 2015

More, On Brightness

This post will address luminaire placement density with good LED downlights, inspired by marketing decisions at Nicor Lighting. Nicor has replaced about-800 lumens, 120° beam angle DLS10 lights, with lights that at 3000°K are 671 lumens (DLS4), or 1022 lumens (DLS56). Builders and consumers need better understanding of the density of placement of such lights. I believe less brightness and less spacing between lights, is good design.

Here is one reference in this:  


The range of human vision.

Some examples of typical horizontal light levels are as follows:
  • Cloudless summers day with full sun - as high as 200,000 lux.
  • Clear moonlight night - 2 lux.
  • Typical clerical office -  500 lux.
  • Underground car park - 20 to 50 lux.
  • Floodlit sports stadium (rugby) - 1500 lux.

This resource says:

Positioning of Lights

Where to position the lights in a new home or renovation is often a worry as once the wiring is in pace it is expensive to make changes.
The following guidelines are based on practical rules of thumb and may be helpful in planning how to place your lights.

For general lighting in the home downlights with the equivalent of a 100 Watt incandescent are a good choice.

Delete the rest of this copy from the web, as it displays incorrectly. The links above work, and are useful.

Much more is needed in this post, wanting a rule book on spacing between LED luminaires dependent on brightness and ceiling height.

If you have lots of can lights at spacing good for 100 watt point-source bulbs, a very common need, Nicor now offers no solution.

DLS4 may be bright enough, but is not compatible, I would happily take out the can lights, swapping in 4" junction boxes for the then-modern DLS4 installation. You would be very happy with results. I can do such patch-outs affordably in  a half hour. Does anyone else do this?

DLS56 will be too bright at 100-watt bulb pitch on eight-foot ceilings. DLS10 did the job well, clipping in more-easily in most situations. We still need DLS10, 

Sunday, June 28, 2015

Review, Nicor DLS4 Surface Mount LED Downlight

A 6/2/2016, on hold with Nicor, add this: Do not buy this light. I have returned my unused inventory of sixteen to Thomson Electric, as any seller would allow. I wish to return others rejected by customers, as defective. Lights are extremely glaring, with the foolishly tight array of diodes burning through the lens. This is reported in two prior posts:

Too-Bright Lights 

Luminaire Luminance Definitions 

I am selling my remaining nine DLS10 today. Now, what will I do? Can I expect corrective innovation from Nicor? Perhaps these questions will be answered, as I just asked.

A two-product family replaces Nicor's beautiful DLS10 LED downlight . I hope demand will allow continued sale of a poduct like 750 lumens 3000°K DLS10. For now, I must get used to the new offerings. I have started out with purchase of one each at best price, from Thomson Electric.

Nicor DLS4 

Nicor DLS56 

My study of these lights is captured in a Picasa Web Album , then a resource for blog posts. The DLS56, 1022 lumens at 15 watts, will be reviewed separately. First warm up to the new DLS4, 671 lumens at 10 watts. This is only slightly less bright than about-750 lumens Nicor DLS10, and might be used wherever a DLS10 has been used.

Observe the 3000°K DLS4 on my comparison test stand left side. I wire in a porcelain fixture to avoid cutting off the A19 plug.

This serves a notion that luminaires should be push-pluck, serviceable without tools. Spring engagement with the bracket is firm and intuitive. Simply wedge from ceiling, to detach.

Compare first with a 100 watt incandescent bulb at stand right side. Also in view are some Sylvania luminaires that are comparable to DLS56.

DLS4 at left and 100-watt light bulb, at full brightness in a Cooper DAL06P dimmer circuit. Where a 100 watt light bulb gives task illumination equal to a 450 lumens 120° beam angle downlight, Brightness Number B4, the 671 lumens DLS4, 100° beam angle, is about B6, 50% brighter.

The light bulb, at right, is not dimmable. The DLS4 dims well and almost silently, without change of color.

Now swap in a 65 watt incandescent downlight, about 650 lumens.

DLS4 3000°K at left, 65 watt incandescent downlight at right. Brightness is a good match by my sight judgement and by discrimination of my Canon Digital Rebel. The 65 watt bulb gives ugly rendering of wall color corresponding to about 2700°K LED color.

The incandescent bulb again is not dimmable.

At about half-bright with Cooper DAL06P dimmer, the incandescent color is becoming ugly orange.

The box back side includes data of test lumens, and luminous intensity , lumens per square foot (footcandles).  We don't yet have luminous intensity numbers for competing luminaires. Where I say the DLS4 is Brightness B6, that is yet more-useful than a particular footcandles measurement. 

Comparative brightness is what really matters, and that will be little dependent upon distance projected or being a bit off-center. I think my setup off-center fairly takes away advantage of a highly-focused luminaire. I won't care much whether beam angle is 120°, or 100°.

At 3/20, 2016, express some negative views of Nicor DLS4, where it is rejected as eye-jarring on an 8' hallway ceiling. Too much light is delivered through its small lens, with density 50% larger than that of Nicor DLS10 and Nicor DLS56. The DLS4 will give pleasant light if dimmed 30% or more. This represents Nicor DLS4 design error. A music room is illuminated far better with Utilitech 0752125, than with Nicor DLS4. Appreciate the added brightness, 900 lumens vs 671 lumens, at each light, and lights become easier to look at. A 4" light should not have been offered at more than 500 lumens. I have come back to find unhappiness the Nicor DLS4 is not simply an improvement of 4" Glimpse lights, 450 lumens. I will use up an inventory of Nicor DLS4, perhaps dimmed, as closet lighting not seen.

The following photos are from post Trial Placement of LED Disk Downlighting . In the lower photo, with DLS4, observe a still-wet patch of the needed ceiling cut. The now-invisible patch is with flexible grout ; use no tape.