As of January 1, traditional 75-watt incandescent light bulbs can no longer be manufactured in the United States, continuing a national transition to more efficient lighting by 2014.

The first phase of the new federal light bulb standards, as set forth in the Energy Independence and Security Act of 2007, went into effect last January with traditional 100-watt bulbs being phased out (though Congress de-funded the enforcement of those standards at the end of 2011). Under the regulations, all bulbs must be 27 percent more efficient. (See related post: “LED Holiday Lights Boost the Season’s Energy Efficiency.”) That means a bulb that used to use 75 watts must now use fewer than 53.

Conventional incandescent light bulbs tend to cost