Should “omnidirectional” be a key feature in an LED bulb review?

First, a lighting jargon translation: The lighting industry refers to the thingies that screw into a light fixture – the light sources that  consumers call light bulbs – as ”lamps”. Mere mortals think of lamps as being the devices that hold bulbs and sit on tables, but that’s not how lighting industry experts talk. An “A lamp” is the industry term for an Edison-style light bulb.

It’s tempting to think that LEDs bulbs are inherently state-of-the-art, relying as they do on a fairly young technology, but that’s not Philips 10W LED non-dim bulbthe case. Many of the LED lights, especially those carried in the big box stores like Kmart and target, were designed several years ago, and their efficacy as well as color quality are sadly dated. So the recent US Department of Energy CALiPER Snapshot report on LED A lamps (pdf) has good news: The mean efficacy of all A lamps listed by LED Lighting Facts has steadily increased, and is now at 69 lm/W. And about 91% of currently listed LED A lamps have a color rendering index (CRI) in the 80s, with most of those products having a color temperature of either 2700 K or 3000 K. The database is now about 4 years old, and has over 9,600 active products.

The report notes that the biggest differences between LED bulbs are “luminous intensity distribution, color quality, dimming, and compatibility with controls.”

Omnidirectionality is not free

However, there was one phrase that I found odd in the Snapshot and that was “95% … meet the current Energy Star efficacy criterion.” That’s great, but Energy Star requirements include more than just efficacy targets, and one of those is that the bulbs shall be omnidirectional. Omnidirectional is covered by the term “luminous intensity distribution” referred to above and thus is one of the key differentiators between LED bulbs. And no, the large majority of LED bulbs are not omnidirectional, due to cost and packaging constraints and thus cannot meet Energy Star requirements.

This fascination with omnidirectional lights comes from the legacy view of the LED industry that LED lights not duplicate the shortcomings of early  CFLs (compact fluorescent lights), which were a poor  replacement for incandescent bulbs in design as well as quality.

But what if consumers don’t want or care about omnidirectionality? Because of the uni-directional nature of LED components, a spotlight illumination pattern is more easily – and cheaply – achieved. And here’s the rub – spotlights are preferable for many light bulb applications, such as track lighting, fan lights, wall sconces, and ceiling lights.

The Lighting Facts program, which is a younger organization than Energy Star, seems to be recognizing this trend: Last August the database began allowing multiple classifications for bulbs, including decorative, directional, linear, omnidirectional, and “other”, and the name of lamps covered in the database also changed, from omnidirectional to simply A lamps.

Spotlights fill a need

Perhaps Energy Star should make a similar change, and widen its criteria so that directional bulbs such as the inexpensive snow-cone design can achieve Energy Star certification.

My interest is not idle: I’m in the midst of updating my LED 60W light bulb recommendation for The Sweet Home and Tested, in large part because so many LED bulbs have been introduced in the second half of this year. In general, I like to stick with Energy Star criteria as a starting point, in large part because many/most utilities require that bulbs meet Energy Star to qualify for utility rebates, and also because people have been trained (and rightly so) to expect Energy Star  certification as a guarantee of good performance and good quality.

(In fact, I took a lot of flack originally for recommending the Cree bulb because at the time it was not Energy Star, and several/many/ouch readers called me on that. My reasoning was that the Cree 10-year warranty was a good enough indicator of the bulb’s lifetime performance (another Energy Star criteria) until the bulb received its Energy Star certification, which it soon did. But I sure noticed readers’ interest in Energy Star.)

Maybe consumers are ready to move past the idea of an incandescent bulb setting the bar for all future lamp technologies. What are your thoughts? If omnidirectionality isn’t a factor in your purchasing decision, and perhaps you’d actively prefer directional lighting, should the Energy Star certification not be a requirement for a “Best Bulb” recommendation?


  1. says

    A reader comment via email: “Yes, information on lamp dispersion is something I value. For instance, the lamp light dispersion featured in the picture in your current piece would be a problem where my wife likes to read, because the floor lamp needs an A19 type lamp that directs a fair amount of the light downwards, and that lamp does not! Typically, with A19 replacements, omnidirectionality is important to me. Also, with down facing lamps, like R30s, I have some concern about what is meant by spot and flood, and some indication of beam spread would be helpful.”

  2. Sean Walmsley says

    EnergyStar clearly isn’t keeping up with trends in lighting. For example, I designed my new house with as many recessed lights (lamps??) as possible (all PAR20s), and have been converting to LEDs as more dimmables came onto the market. However, one of the major concerns I have is that even 2700K LED lamps wash out woodwork (e.g., maple cabinets in the kitchen), so I’m forced to continue using halogens in those applications. Is this just a case of getting used to the change in color temps (i.e., I need to get over it), or a matter of which LED lamps I use, or a failure in LED technology to replicate the warmth of a halogen lamp?
    BTW, your articles are so informative and interesting!

  3. Carlos Masallach says

    Hi Margery:
    Yes, omnidirectionality MOST be part of the specification, I´m really glad that the GE people got their way thru all the energy star drafts and there is an Appendix A-1, sure it´s not perfect but is a testable quantity. There is room for non-omni A-19 like lamps on lots of luminaires styles, but please let the layman (or woman) know what kind of a product they are paying for.
    Just an additional commentary on the energy star lamp requirements: well it looks finally somebody noticed that you only need to wires to connect a lamp bulb to mains so there is no explicit requirement for the common mode transient test.

  4. MattPete says

    Consumers expect omni-directionality from A19 bulbs. If they need a directional downlight, they should be directed towards a Br20,30, or 40. In addition, BR-series lights are designed to hang upside down in open cans — A19 designs may no be designed for that purpose and might not get sufficient ventilation.

  5. Juan Velez says

    Omnidirectionality is a MUST for A-type lamps. By definition the A-shape lamp is an omidirectional light source.

    Are consumers ready to move past the incandescent lamps as being the bar which light sources are measured? Absolutely not! The concern shown by some consumers with the phase out of less efficient lamps, which are by the way omnidircetional lamp shapes, should be enough to answer this question.

    Aside from Margery’s testing using her ‘light ring’ setup, shown above, no one has realistically demonstrated in a real world set up what omnidirectionality means. Energy Star’s Appendix is a lab environment setup and does little to educate consumers on what omnidirectionality is and what it means to them.

    Margery I have put together some ‘real world’ info on this subject, drop me a line if you would like to see what I have shown in regards to omnidirectionality.