LED bulbs are coming down in price - do i want warm white or cool white, and why?

[TreasonousBastard]

5. You probably want a bulb with...

3000-3500K and a CRI of 90 or above. Of course, hardly anyone bothers to tell you what the actual color temp or CRI is.

CRI, or Color Rendering Index, is a term from the fluorescent days where 100 is 100% rendering of colors-- natural light. When I worked for Duro-Test I sold fluorescents that went as high as 95% when the typical cool white was around 75% and warm white in the 50's. Cheap "Daylight" fluorescents were just kinda blue and rarely had much red in the color balance. More expensive ones, like ours, had a good color balance and were used in art shops, textile production, and other places where accurate color was needed.

5000K is about the color temp of sunshine in a clear sky. 7000K and up is "north light"-- the sky without the sun. An old incandescent lamp is around 2700K, with halogens a little higher. Photofloods were 3200-3500K.

If they don't give you the color temp on the box, there's no telling what else they don't give you, so pass 'em up.

I've found the most pleasing light to most people is a color temp of around 3000K or so, since it's closest to the light bulbs we're used to. Next most pleasing (and my personal favorite) is 5000K. In that picture in Post #3, the "natural white" one would probably be the best bet.

But, there's that CRI to worry about, and hardly anyone publishes that- they think it just confuses people.

BTW, if you compare the lumen output per watt, you'll notice that LED's aren't really that much cheaper to operate than CFL's at this point, and until they get much cheaper and increase the light output, they are actually significantly more expensive.