Katherine Salant’s cover story in late December on LED lights generated lots of reader questions. She answered some questions in her column Saturday. Here, she answers more:
Some A19 LED packaging says “Full Light Distribution,” “360 Light All-Around,” “Balanced Light” or “All Around Light Distribution.” Is this important?
Yes. It means that the light-emitted bulb is “omnidirectional” — it goes in all directions and the bulb can be used for both general lighting and task lighting. This distinction was unnecessary with the old incandescents because all of them were omnidirectional.
Most of the A19 LEDs have this feature, but not all of them do, so you have to check the packaging.
When an A19 LED is not omnidirectional, the light only goes up, illuminating a smaller area. Most homeowners will find this type of LED, which generally costs less, works well for creating “atmosphere” but it’s unsatisfactory for reading and other close work.
Which A19 LEDs did you prefer in your home testing?
Before I answer, a brief review of Kelvin temperatures is in order because it was a factor in how I chose the particular bulbs to test. In the context of light bulbs, Kelvin temperature indicates the color of the light emitted from the bulb. It was never a factor in selecting incandescent bulbs because they all had the same Kelvin temperature of 2,700 degrees (written as 2700K).
But the A19 LEDs can have one of three different Kelvin temperatures and the differences are significant. An A19 LED with a 2700K temperature has a warm, yellowish light that’s intended to mimic incandescent bulbs. A 3000K A19 LED has a crisp, whiter light intended to mimic the still-available halogen bulbs (these look like incandescents but they are about 25 percent more efficient). A 5000K A19 LED has a bluish light that mimics daylight. I only tested the A19 LEDs that mimic artificial light, and I only tested ones that are available at Home Depot, Lowe’s, and Wal-Mart because these nationwide retailers are accessible to most consumers.
For my home testing, I used two identical bedside table lamps at night. I compared the 3000K A19 LEDs to a 60-watt halogen bulb and the 2700K A19 LEDs to a 60-watt incandescent bulb.
Overall, I found that the light emitted from all the LEDs that I tested is close to what they are intending to replace. The differences are subtle and nuanced. You won’t walk into a room that is lit with any of these and immediately want to walk out.
Of the three 3000K A19 LEDs that I tested, two — GE’s “Energy Smart” with fins (Home Depot $35) and Utilitech Pro (Lowe’s $10) — produced a light that was slightly whiter than the halogen’s but nonetheless very pleasing. I also tried both in my desk lamp where they worked well. The third bulb that I compared, Philips CorePro (Home Depot $10), is not omnidirectional and only suited to general lighting.
All of the six 2700K A19 LEDs that I tested produced a color of light that was close the incandescent’s but slightly more yellow or slightly more white (I tested more 2700K bulbs because these are more popular and there are more choices).
Cree’s “Soft White” TW series (Home Depot online $18) came the closest to the incandescent light, but Cree’s “Soft White” (Home Depot $13), Philips “Soft White Light” (Home Depot $15) and Sylvania’s “Ultra” (Lowe’s $20) were also very close. I would be happy using any of these for both reading and general lighting. Philips “Slim Style Bulb” (Home Depot $10) produced a noticeably whiter light; I have also tried it in my desk lamp and liked it there. GE’s “Energy Smart (Wal-Mart $11) is not omnidirectional and only suited for general lighting.
When you get ready to purchase a few A19 LEDs, you may find that the ones I describe here have been superseded by newer versions from the same manufacturer. Compared to other industries, the A19 LED manufacturers are changing their products at a dizzying pace. Philips introduced its first A19 LED replacement bulb for the 60-watt incandescent in 2010; the one it offers now is the fifth generation.
How can I find out if an A19 LED will work with the dimmer in my house?
You can contact the manufacturer of the dimmer. (If the name is not visible on the faceplate with the light switch, you may have to remove it and look inside the switch box that is recessed into the wall.) Most A19 LED manufacturers list compatible dimmers on their Web sites.
Alternatively, you can buy an A19 LED bulb and test it with your dimmer. You won’t cook the bulb if the dimmer is incompatible; you just won’t like the results. The symptoms of a mismatch are audial — a buzzing noise that increases with dimming — and/or a flickering, strobe-light effect.
If your dimmers are compatible, you will still notice two significant differences compared with their performance with an incandescent bulb. The first is the amount of light that is still visible when the dimmer is turned all the way down. Because the LED is so much more efficient, the slightest amount of current will illuminate the bulb, but some dimmers can be adjusted so that no current passes through when the dimmer is turned all the way down.
The second difference is the appearance of the dimmed light. As an incandescent bulb is dimmed, both the amount of light and the color temperature are reduced. The light becomes more reddish, which enhances your perception that it is becoming more faint. When an A19 LED is dimmed, only the amount of light is reduced; the color temperature of the light remains the same.
As a consequence, when the LED is dimmed 70 percent, it will appear to be brighter than an incandescent dimmed an identical amount.
Can an LED be used in an enclosed fixture?
Yes, but only some brands. The issue is the amount of heat that can build up in the enclosed fixture. LED bulbs are very sensitive to heat; if the air in the enclosed fixture becomes too hot, it will shorten the life of the bulb.
If you want to install an A19 LED 60-watt equivalent in an enclosed ceiling fixture (the most common type of residential enclosed fixture), read the packaging carefully. Most say that the bulb cannot be used in this way. The only ones I found that can be are Cree’s A19 LED Soft White and its A19 Soft White TW Series. The fine print on Cree’s packaging, however, warns against mixing bulb technologies in the fixture (using a LED with a CFL or an incandescent) because the other bulb types produce so much heat that they will adversely affect the LED.
Katherine Salant has an architecture degree from Harvard. A native Washingtonian, she grew up in Fairfax County and now lives in Ann Arbor, Mich. If you have questions or column ideas, she can be contacted at firstname.lastname@example.org or katherinesalant.com.