This January federal efficiency standards will essentially outlaw classic incandescent bulbs; any alternative must be a brighter idea.
All eco-bulbs are not created equal. Compact fluorescent lights are up to five times more efficient than incandescents, but they contain mercury, which can make them harder to recycle and in some states illegal to trash. Light-emitting diodes (LEDs), by contrast, can go at least 25,000 hours before flickering out—about three times longer than CFLs—which means, hour for hour, they require a sliver as much energy to produce. LEDs contain no mercury, and—mood-lighting fans, rejoice!—they cast a warmer glow.
When swapping outdoor lights for LEDs, choose motion-sensing models; doing so cuts energy use even further.