The AmbientLED from Philips is the latest LED light designed to replace the 60 watt bulbs in people’s homes. Unlike older LEDs I tested, this light is definitely up to that job. It gives off 800 lumens of warm light, while running on 12 watts. It’s the first LED light to earn an ENERGY STAR qualification. To qualify, a 60-watt LED equivalent must have a minimum light output of 800 lumens, a color temperature of 2700K (for soft white light), color rendering index (CRI) of 80 and a minimum three year warranty, among other requirements.

The AmbientLED’s illumination is omnidirectional, closely matching the way light is thrown from an incandescent bulb. In fact, I’d be hard-pressed to tell the difference between this LED and an incandescent in a blind test.

It’s good to see LED replacements coming to market that more closely match what people are accustomed to in their homes.

The light sells for $39.95 online at Polar-Ray.

Zetalux LED Light Bulb

Update: See our latest post on LED Light Bulbs For The Home.

I recently had the chance to test two state-of-the-art LED light bulbs from EarthLED. LED bulbs have many advantages over incandescents and compact fluorescent: they use very little power, they last 10 years or more, and they contain no hazardous substances. They are also tough: they can be dropped and turned off and on repeated without damage, they can operate in very cold or warm temperatures.

LED bulbs can also save you money in the long term, because an incandescent bulb requires about $300 worth of electricity over ten years of use. The LED bulbs cost $40 (for the 60 watt equivalent Zetalux) and $50 (for the 100 watt equivalent Evolux), and their cost to run over ten years is about $38.

The Zetalux

The first EarthLED bulb I tested was the ZetaLux LED (pictured above). This bulb produces a pleasing warm white light.

Until recently, LED bulbs were only capable of producing a stark, cool white light, so I was happy about the color temperature of this bulb (it’s rated at 3000K). The bulb didn’t need to warm up like a compact fluorescent, and there was no flickering at all.

The Zetalux uses a CREE LED engine and features a high CRI or Color Rendering Index (75 for cool white and 80 for warm white). The bulb is rated at 7 watts. However, when I tested it with a Kill-A-Watt meter it was drawing only 5 watts.

The warm white version of the Zetalux produces 350 lumens, and the cool white produces 450 lumens. Comparing LED bulbs and other bulb solely on lumens is tricky because LED bulbs tend to make better use of their lumens in recessed fixtures (see this page for more details). EarthLED says the bulbs are equivalent to a 50-60 watt incandescent bulb.

The Zetalux LED Bulb illuminating my hallway.

The Zetalux currently sells for $40. The bulb costs about $2 per year to run, assuming it’s left on 8 hours a day and the cost of electricity is $.10 per KWh.

The Evolux

The second bulb I tested was a cool white Evolux. This 13 watt bulb produces 1075 lumens, and according to EarthLED is equivalent to a 100 watt incandescent. This bulb is definitely bright — it illuminates my garage quite well.

EarthLED says the Zetalux and Evolux will become the first FCC and Underwriter’s Laboratory (UL) listed LED light bulbs on the market at the end of 2008. Both bulbs are RoHS compliant.

EarthLED will be releasing a dimmable version of the ZetaLux, and a new version of the Evolux in early 2009.

These bulbs are available from GoGreenSolar

Bulb Types

Bulb Base Types

Color Temperature
The color temperature of light refers to the temperature to which one would
have to heat a "black body" source to produce light of similar spectral
characteristics. Color Temperature is expressed in degrees Kelvin (K). Low
color temperature implies warmer (more yellow/red) light while high color temperature
implies a colder (more blue) light. Moreover, the "color temperature" of
a lamp refers to how reddish, greenish or bluish the lamp appears. If the lamp
appears reddish, it has a lower color temperature (e.g., 2500K-3000K) and is
considered to be "warm" in appearance. If the lamp appears to be
bluish, it has a higher color temperature (e.g., 4000K-4500K) and is considered
to be "cool" in appearance.

Warm White: 2500° K to 3000° K
Cool White: 4000° K to 4500° K
Day Light: 6200° K to 6800° K

Color Rendering Index
The Color Rendering Index, or CRI, is a term in photometry used to describe
the effect of a light source on how well it renders colors. In essence, the
Color Rendering Index (CRI) is a numerical system that rates the "color
rendering" ability of fluorescent light in comparison with natural daylight.
If a lamp has a low color rendering index of 50, it does not render colors
very well. If, however, the lamp has a color rendering index of 80 – 95,
its ability to render colors is thought to be very good to excellent. A CRI
of 100 is considered natural daylight and is assigned to the sun itself.