Move Over Watts, Lumens Are King

60-watt incandescent bulbThe Federal Trade Commission, the agency charged with protecting America's consumers, is putting new labels on light bulb packaging. Modeled after nutrition labels on food, the Lighting Facts labels are designed to help buyers save money by selecting more efficient bulbs.

Wattage, the amount of energy a bulb uses, is being replaced by lumens, which measure brightness as the defining metric. Many of the new lamps on the market produce a brighter light with fewer watts. These two examples from the Department of Energy make the comparisons crystal clear.

Lumens and light appearance--about the same; energy costs and life expectancy--the CFL is a clear winner. (Yes, there's mercury in the fluorescents, a separate issue.) But it is going to take a massive educational effort to wean consumers off watts. Not that we're going to have a lot of choice. New energy standards mandated by Congress will effectively phase out traditional low-efficiency incandescent bulbs from the U.S. market over the next few years.

13-watt compact fluorescent bulbAs reported recently in The Washington Post "Watts will no longer reflect the traditional lighting strength of the bulb. On January 1, 2012, manufacturers will have to produce the equivalent of a 100-watt bulb using 72 watts of power; a year later, they will have to replace 75-watt bulbs with ones that are 28 percent more efficient; by January 1, 2014, they will have to do the same with 60-watt and 45-watt bulbs."

Some conservatives, both in Congress and the media, are calling for a repeal of the law while industry representatives and environmentalists are worried that the transition won't be properly funded and doomed to failure. Let's hope for real leadership here; the U.S. is already trailing many other parts of the world in phasing out high-energy intensive bulbs.

In the meantime, courtesy of DOE, here is a handy refresher summary of product performance to help with those new labels:

• Lumens measure light output. The higher the number, the more light is emitted.

• Lumens per watt (lm/W) measures efficiency. The higher the number, the more efficient the product.

• Watts measure the energy required to light the product. The lower the wattage, the less energy is used.

• Correlated Color Temperature (CCT) measures light color. "Cool" colors have higher Kelvin temperatures (3600-5500 K); "warm" colors have lower color temperatures (2700-3000 K). 

• Color Rendering Index (CRI) measures the effect of the lamp's light spectrum on the color appearance of objects. The higher the number, the truer the appearance of the light on objects. Incandescent lighting is 100 on the CRI.