SAN FRANCISCO — It sounds like such a simple thing to do: buy some new light bulbs, screw them in, save the planet.

But a lot of people these days are finding the new compact fluorescent bulbs anything but simple. Consumers who are trying them say they sometimes fail to work, or wear out early. At best, people discover that using the bulbs requires learning a long list of dos and don’ts.

Take the case of Karen Zuercher and her husband, in San Francisco. Inspired by watching the movie “An Inconvenient Truth,” they decided to swap out nearly every incandescent bulb in their home for energy-saving compact fluorescents. Instead of having a satisfying green moment, however, they wound up coping with a mess.

“Here’s my sad collection of bulbs that didn’t work,” Ms. Zuercher said the other day as she pulled a cardboard box containing defunct bulbs from her laundry shelf.