Thomas Edison is credited with inventing the practical incandescent light bulb. The incandescent bulb that most of use today to light our homes hasn’t had many technology upgrades from Edison’s day. In its most basic form, an incandescent light bulb is a (carbon) filament, encased in glass, where the filament heated with an electric current until it produces light. Don’t get me wrong: it was a great invention that heralded us into a modern age with the benefit of immediate light with good illumination, color characteristics and dimming capabilities. And it remains the least expensive practical light source for the home and office (roughly 25¢ a bulb). However, energy efficiency was never a major goal of incandescent lighting technology. Indeed, incandescent bulb use has been attributed to high energy consumption and a build-up of harmful green-house gasses.

Now, regulations have been put into place in the U.S. and around the world that could be the death knell of that great invention. For example, the Federal Energy Bill of 2007 {42 U.S.C. 6295(i)} phases out inefficient incandescent light bulbs beginning in 2012. By 2014, incandescent bulbs that produce 310-2600 lumens of light are banned, with exemptions for light bulbs using fewer than 40 Watts or more than 150 Watts, several classes of specialty lights (think appliance lamps), rough service bulbs, 3-way bulbs, colored lamps, and plant lights. By 2020, all general purpose bulbs would need to be at least 70% more efficient, which certain exemptions, such as floods, 3-way, candelabra, colored, and other specialty bulbs. Certain states, such as California, had also implemented statewide standards, and similar legislation was proposed in Connecticut and New Jersey. However, the federal law essentially preempted these state efforts.

One energy-efficient alternative is the compact fluorescent lamp or CFL. With the downturn in the economy, Americans have finally begun to embrace CFLs. These little fluorescent bulbs have a built-in ballast and the typical screw base so that a CFL can easily replace a traditional incandescent bulb. CFLs are more expensive than traditional incandescent bulbs (were approximately $3/bulb, but now closer to $1/bulb), but they use about 75 % less energy and last approximately 5 years (as opposed to months with a traditional incandescent bulb). However, CFLs contain trace amounts of mercury and must be disposed of properly. Further, the light color is not the same as an incandescent bulb (anyone looking at themselves in front of a mirror under fluorescent bulbs versus incandescent bulbs will know exactly what I am talking about!) and they do not dim.

But necessity has and always will be the mother of invention. Don’t write off incandescent bulbs just yet. Some lighting manufacturers have been researching ways to capture heat loss through the application of special reflective coatings to capsules that surround the bulb filament. In essence, the coatings function to reflect heat back to the filament transforming the heat into light. One such manufacturer is Deposition Sciences, Inc. of Santa Rosa, California. They are refining their films and heat recovery has in early tests has shown energy savings in the 30-50% range.

It remains to be seen whether the commercialization of this new technology will meet new energy efficiency regulations, be cost-effective, and appeal to the consuming public. Stay tuned.

Of course, LED lighting has made some inroads for more general use. Watch for a future blog post on the status of LED lighting technology.