There are few electricity end uses more essential than lighting. Lighting was the primary driver behind electrification of our homes and businesses. For decades, however, there were few improvements to lighting technology. We had a functional, affordable technology that consistently delivered what we desired. The problem with traditional incandescent lighting technology is its gross inefficiency. In fact, over 90% of the energy consumed by incandescent lighting produces heat rather than light. Changes in lighting technology, therefore, are related to energy inefficiency rather than dissatisfaction with the output of the product.
The Energy Independence and Security Act of 2007 (EISA) included a number of provisions designed to move the United States to greater energy independence and security. Most consumers know the EISA as the “light bulb law.” The impact of EISA on lighting was to increase the lumens produced per watt of energy consumed. The law did not ban incandescent lighting by name; however, traditional incandescent lamps simply cannot meet the new efficiency standards. The two primary replacement technologies that have emerged are compact fluorescent (CFL) and light emitting diode (LED).
Compact Fluorescent Lamps
CFLs have been the dominant technology to date. CFLs contain argon and mercury vapor housed in a tube coated with fluorescent paint. An integrated electronic ballast regulates the electricity current through the gas. Compared with incandescent lamps, CFLs use about 70% less energy per lumen and can last up to eight times longer. The initial cost of purchasing CFL lamps is higher than incandescent lamps but the energy savings can reduce payback periods to less than one year. The negative issues associated with CFLs are longer warm-up times, unsuitability for dimmer switches, light color, bulb shapes, and base types. Concerns about CFL disposal and mercury content have also impaired consumer switching rates.
LEDs Lower Electricity Costs
LED lamps solve many of the problems encountered with CFLs. LEDs produce light by the flow of electrons through positively and negatively charged semiconductor material. LEDs are dimmable, suitable for all lighting applications, and reach full brightness instantaneously. Furthermore, they can be up to twice as energy efficient and last twice as long as CFLs. One of the drawbacks to LED lighting is how it renders light. There is no such thing as white LED light. Therefore, a combination of LED color blending and bulb coatings are used to produce white light. Another issue with LEDs is their cost. LED lamps can range in price from $12 to $25 apiece.
There is little doubt that CFLs will play a limited role going forward as LED color rendering improves and costs decrease. CFLs are, in a way, a transitional energy efficient technology that has served to move consumers away from incandescent lamps and provide time for LEDs technology to advance. However, another lighting technology has emerged that may challenge LEDs.
Other Energy Efficient Lights
Induction lighting uses an electromagnet to excite mercury particles suspended in an inert gas. Originally developed by Edison rival Nikola Tesla, magnetic induction lighting had previously been restricted to commercial and industrial applications. The Finally Light Bulb Company recently condensed the technology to create a standard size induction bulb for home use. The Finally lamp uses 75% less energy and lasts up to 15 times longer than a standard incandescent lamp. The lamp promises omnidirectional light with the same warm glow and high color rendering of incandescent lamps. As of May 2015, the lamp was awaiting commercial delivery at a cost of around $10.
The bottom line is that energy efficient lighting requires a change in residential energy consumer behavior. Light bulbs have long been regarded as a disposable item. They were low cost, lasted a year or two, and then you just replaced them when you did your routine grocery or general merchandise shopping. Energy efficient lights, however, have a longer expected service life than most other electrical appliances in the home. With service a service life in the range of 15 to 20 years and at a cost of $10 to $25 per bulb, purchasing lighting has transformed into a research and comparison shopping exercise. Prices for LEDs and induction lights should continue to decline and color rendering will more closely resemble that of incandescent lamps. In the meantime, CFLs are a reasonable intermediate option.