What does this say about lighting and, as you select LEDs for your house, what should you look for?
Mark Roush, a lighting consultant and vice president of the Illuminating Engineering Society (IES), an organization that develops lighting standards for the lighting industry, offered this explanation:
The apparent color of an object can vary, depending on the light source that illuminates it. When the same object — in this case a garment — is viewed under the light produced by different kinds of light bulbs, its color may not be the same. In my case, Roush said, the bulbs in the store that made the underwear look black were probably less-costly fluorescents and the ones that made them appear to be navy were probably better-quality and more-costly fluorescents.
The LEDs in my house made them appear to be purple because LEDs have a different spectral range that changes your perception of reds and blues.
But, Roush added, knowing that colors can change under different kinds of lighting and even knowing that colors can appear to be slightly different within a given category of LED light bulb will not be very helpful in choosing one. That’s because there is no standard that addresses the nuanced differences between the LED bulbs of different manufacturers. IES is currently developing such a standard, but it may not be ready for several years, he said.
There is a lighting standard that does measure how colors appear under a given light source called the Color Rendering Index or CRI, but Roush points out that this standard was developed for incandescent light which has very different properties from the light produced by an LED.
The reason that most people have never heard of the CRI is that it is the same number for all incandescent and halogen lighting. The CRI for these bulbs is always 100. The CRI for a LED might be as high as 94, but with the LEDs that are available today, Roush said, the light of an LED with a CRI in the low 80s can be as good as one with a CRI in the low 90s.
After testing nearly 50 LEDs in 14 bulb categories in my most recent LED home testing, I agree with Roush that the CRI for LEDs is not as important as it once was. For example, in comparing the latest A19 and A21 LEDs to the old 60-, 75- and 100-watt bulbs, I found the LED light to be very close to what it is replacing — so close, that in some cases, it is indistinguishable from the old bulbs. All the A19 and A21 LED bulbs that I tested this time had a CRI in the low 80s.
Rather than look to the CRI of an LED bulb, Roush advises consumers to focus on the brand of the bulb. “The manufacture of LEDs are not standardized,” Roush said. “There are many ways to make LEDs, some great and some not so great and you get what you pay for. An inexpensive Brand X LED may not provide the same ‘lighting experience’ as one made by a major brand that likely costs more.”
While I agree that brands matter in the purchase of an LED bulb, I also think that in some applications in a home, the CRI also matters. In my home testing, I preferred the higher CRI LED bulb for a dressing area where you are selecting outfits (the CRI of the LED that showed the underwear to be purple was 94), for a bathroom where you may be applying makeup and for showcasing art work where color accuracy is very desirable.
These are the high CRI LEDs that I tested and recommend:
• Bathroom: Cree’s “Soft White LED 4-in recessed downlight,” which has a “90+ CRI.” (The LED is incorporated into the fixture itself). Home Depot, $19.97.
• Dressing area: Sylvania Par 20, 3000K, 40-degree beam angle with a CRI of 94. Sku number 79098, $37 on some Web sites.
• Art work: Sylvania MR16, 3000K, 35-degree beam angle with a CRI of 95. Sku number 72544, $27 on some Web sites.
The Sylvania bulbs are intended for commercial use. They’re not available in big box stores like Home Depot, but you can purchase them on Web sites like www.ledlightbulbs.com. To make sure that you are getting the correct Sylvania LED bulb, you need to include the sku number in your Web search.