All compact fluorescent light bulbs with the label meet this efficiency recommendation. Compact fluorescent lamps commonly referred to as compact fluorescent light bulbs or CFLs, are 3-4 times more efficient than standard incandescent bulbs. They produce light through fluorescing phosphors instead of a heated filament.
Lumens are a measure of light output.
Covered bulbs have lower lumens per watt. See documentation for a detailed set of instructions.