incandescent

(via Flickr / National Museum of American History)

Up until now, a 2007 federal law tightening energy efficiency standards in the country has stayed mostly under the radar. But on New Year’s Day it became illegal to manufacture or import the most popular light bulbs in the country — the 40 and 60 watt incandescent light bulbs perfected more than a century ago by Thomas Edison.

When stores sell out of their current stock of incandescent light bulbs, consumers will be forced to make the switch to LED, CFL or halogen.  A previous phase in the law already put a halt to the manufacture or importation of the 75 and 100 watt models.