Originally Published: January 5, 2014 6 a.m.
Question: With all the new lightbulb types and specifications, how can you tell which one to select for which use?
Answer: According to the Environmental Protection Agency, lighting consumes 12 percent of total in home energy use, so focusing on new energy-efficient lighting makes a lot of sense. Today's lighting has a number of technologies to choose from, including the original Edison incandescent everyday lightbulb, the newer compact fluorescent lamps (CFL), and the even newer light-emitting diode (LED) bulbs.
Before evaluating the types of lightbulbs, we should understand the components associated with lighting selection. The basic incandescent bulb is the standard to which all others are compared. The labeling only shows its energy requirement in Watts (60W, etc.), but it has other components not generally specified, like its brightness or efficacy level in lumens per watt, its color rendition index or the quality of light to render colors correctly, and its color temperature in degrees Kelvin that describes its relative color appearance. These components are important when purchasing newer CFL or LED bulbs, and when matching the brightness and color of the incandescent bulb you wish to replace.
Incandescent bulbs have the lowest initial cost and are the most inefficient. They have short lifespans and use significantly more energy to produce acceptable light output. More than 90 percent of the energy used escapes as heat, with less than 10 percent producing light. Incandescent bulbs are being phased out because they consume a large amount of energy for the limited light they produce.
Compact fluorescent lamps
First-generation replacement technology for incandescent bulbs was fluorescent tubes. The glass tube is coated with a fluorite coating and filled with a small amount of mercury. Heating filaments warm the mercury into a vapor and, when electric current flows through, the vapor atoms give off ultraviolet light, and the fluorite coating fluorescences, giving off visible light.
Fluorescents come in two forms: linear tube fluorescents used in workshops and utility rooms, and compact fluorescent lamps (CFL) used in more stylish fixtures. The advantage of CFLs is their low power consumption and long life. They only use 25 percent the energy of a standard incandescent bulb and they last up to 10 times as long.
Unfortunately, they have a few disadvantages. One issue is that mercury is a toxic metal that can lead to adverse health affects. They also transmit ultraviolet light, which can be harmful to some people. CFLs can have long start-up times (1-3 minutes); are not readily dimmable; do not like high or low temperature swings; and reliability and lifespans drop when switched rapidly or used over short intervals. Most come from China, and China has many manufacturing quality and reliability problems.
However, one way to minimize these potential problems is to invest in an Energy Star certified bulb. The design and manufacturing process of an Energy Star product requires that it's tested and certified by a third party before the Energy Star label can be attached.
Light-emitting diode bulbs
An alternative to a CFL is the newer light-emitting diode (LED) bulb, which is extremely energy-efficient and long-lasting. The standard and most stable solution uses a phosphor conversion technique, in which phosphors are used to color-tune and convert the LEDs' ultraviolet light into white light.
LEDs have all the advantages associated with CFLs and incandescents and none of the disadvantages. They are more than twice as efficient as CFLs and last between two and a half and five times longer than CFLs. They do not contain toxic materials; they produce negligible heat; are more resistant to breakage; are dimmable; and have instant high intensity light, unlike CFLs. The only discernable disadvantage has been price and aesthetic design, both of which are being addressed.
As with all semiconductor technology, new LED products will likely halve in price every 18 months to two years, and could be the same price as CFLs in 3 to 4 years. Based on this, your current incandescents should get you through.
As with CFLs, Energy Star-certified LED bulbs signify third-party verified reliability and performance.
For more information, visit www.greenhomeenergyadvisors.com/articles-and-technical-information/buying-a-cfl-or-led-light-bulb.