Say goodbye to watts and hello to lumens. Compact fluorescent and LED bulbs use fewer watts, or less energy, to produce the same amount of light, or lumens, as incandescent bulbs. But the color of the light varies by the type of bulb, so you need more information than just a bulb's watts to get the light you'd like.
The Lighting Facts label, patterned on nutrition labels on foods, will give you much of that information. It lists the bulb's lumens, or brightness; its estimated yearly energy cost; how long the bulb is expected to last; its appearance, from warm to cool; how much energy, or watts, it uses; and whether the bulb contains mercury. The label must be on packages starting in mid-2011, but you might see it sooner.