LEDs certainly offer many improvements over antiquated illuminaton. Some comments, since I have worked in the architectural commercial fixture business since before LEDs became relevant:
The best fixtures utilize dedicated ballasts and light sources combined, called light engines - best performance, lifespan and light quality when compared to retrofit integrated bulbs.
The costs of all LED sources has tumbled and now matches flourescent in most cases.
For best illumination, daylight 6500 Kelvin temp is what you want, not below 4000, which becomes too orange. I run moslty 6500 T8 in the garage, but am slowly adding LEDs and replacing as they die off.
CRI should be above 80, current Title 24 compliant fixtures are in excess of 94 IIRC.
100 or 105 lumens per watt is pretty much a standard now, so all LED fixtures will offer amazing efficiency, even the least expensive stuff out there.
Diffusing/blending the output results in better spread and lower hot spots/eye strain if the chips are visible - lots of designers have insisted on this type of output - much easier to achieve with the higher efficiencies.
This means playing with angling the fixtures for reflecting the output and considering matte white walls, ceilings and light coloured floor coverings when possible. Maximize and direct the light you have. LEDs are directional, which is both a blessing and a curse, depending on application and fixture type.
Heat is the enemy, this is why most retrofit lamps will not last anywhere near the typical 50-100 000 hours; we still manufacture plenty of fixtures that accept those - typically about half the output and 1/5-1/10 the lifespan.
Too much light is better than not enough, consistent, even illumination is paramount, especially for us senior citizens - when there is plenty of light, our eyes reduce the retina opening (like a F16 stop on 35mm camera lens) for way better depth of field and focus. The HF $20 fixtures are an amazing value - I bought a few but haven't installed them yet - they are 4000k IIRC, likely 75 CRI or so. we manufacture some linear fixtures that produce 2800 lumens per foot out of a 2"x4" extrusion - app 50/50 up and down. The number one inquiry from the market is - can you dim them down lol.
Fun Facts: 5000k blueish hue is used in high end car detailing shops to magnify the flaws in the paint finish. Sunlight is near 6500k depending on location, weather and time of day/ year, since the atmosphere affects colour - think sunset vs sunrise etc.
Tunable color is coming - from warm to daylight for increased productivity and attention span in schools. Philips in Europe started researching and participating in this about 10 years ago; now some high end spaces have sensors that match the interior lighting colour index with the actual outdoor ambient lighting for perfect blend and not influencing the human circadian rhythm.
I have no knowledge of the blue UV issue mentioned, but I'm sure it's a thing. Human Eye fatigue exists with LEDs for sure, as with all artificial illumination.
a 16 year old hooligan stuck in a 55 year old's carcass
Last edited by tulowd; 11-08-2019 at 11:35 AM.