'A-lamp' is the technical designation of the standard incandescent general illumination lamp, indicating its bulb shape and omni-directional light distribution pattern. Most household lighting fixtures were designed around the use of these lamps so there are many sockets in existence throughout the country. These lamps are easily dimmable with standard household dimmers, from old rheostat controls to new electronic versions. As the lamp dims, the color becomes a warmer, deeper yellow like a candle, a quality many consumers enjoy.

Lighting efficiency standards are changing, and the general service incandescent A-lamp will not meet the new standards established by Congress. To assure that more efficient products are available, the USDOE was directed to support the development of more efficient technologies and products, which resulted in the development of the Solid State Lighting Program. As part of this program, the USDOE held a contest challenging manufacturers to develop an LED lamp to replace the 60 watt incandescent A-lamp. The new lamp must have the same lighting qualities but be much more efficient than the 60 watt incandescent. Philips Lighting won the contest and was awarded the L-Prize for an LED product (see information below). 

Many companies are producing LED consumer products that mimic the shape of the old A-lamp but do not meet the new lighting power or distribution requirements, nor do they have good dimming capability. Other manufacturers are getting close to Philips’ achievement and even higher output models are now on the market. Dimming is a particular problem because LEDs do not have the same electrical characteristics as incandescent lamps. Standard dimmers used in households and hotels were designed to operate incandescent lamps, thus both compact fluorescent lamps (CFLs) and LEDs may experience problems such as color shifts (not toward a warmer yellow), flickering and other issues. Some lamp manufacturers specify which dimmers their products are compatible with, while others simply claim their bulbs are dimmable with no guarantee that the color will be pleasing or that the equipment will work effectively. Dimmers designed to operate with LED products may help resolve this problem.

Although manufacturers are eager to have their products purchased, some products on the market may disappoint consumers due to their poor performance and high cost. As with any purchase, consumers should do their homework and ensure they are buting from a reputable source with a proven technology.

Because of the way LEDs work, the internal heat they create must be removed or their life is greatly shortened. Many existing residential lighting fixtures may retain enough heat to damage LED lamps. When LEDs fail, they do not immediately stop emitting light. With some LEDs, the light gradually fades and may not be noticed for a long time; with others, the transition is more dramatic. In any case, the consumers will not be getting the light they expect and may find they are experiencing eyestrain or require additional back-up lighting.

The lamp of interest in this category is the Philips A-lamp that won the USDOE L-Prize competition. The L-Prize lamp is dimmable down to 10% light output when used with modern dimmers. The prize specifications and the specifications of the actual A-lamp that won the L-Prize winner are as follows:

Source: http://www.usa.lighting.philips.com/lightcommunity/trends/l-prize/lprizeinfo.wpd

Standard incandescents and CFLs are currently the most commonly used residential lighting technology in single-family homes, residential facilities and the hospitality markets. All of the incandescents and some of the CFLs are dimmable, though they do not perform equally well. 

Incandescent lamps work in nearly all household fixtures and control systems, which is logical since fixtures have been designed for incandescent lamps for decades. The Color Rendering Index of incandescents is 100 by definition, and the color temperature is 2700K. Incandescents can be exposed as bare lamps or hidden inside of fixtures (even fixtures that are fully enclosed) without affecting their performance. New lighting standards are making the use of halogen incandescent lamps an option thanks to improved lamp life and efficacy, and they are compatible with the same controls and fixtures that were designed for use with standard incandescents.

CFLs are limited in which control systems may be used, what fixtures they fit, and generally cannot be in fully enclosed fixtures because the heat build-up damages the ballast. CFLs are available in 2700K for residential use, as well as “cool” or “daylight” models at higher color temperatures. These colors may vary by brand, so having all the lighting in a space appear the same can be an issue if consumers are not attentive.

New construction frequently requires ENERGY STAR rated lighting fixtures in order to meet more rigorous energy code requirements.

LED A-lamps started reaching the consumer market in early 2010, with prototypes circulating for a while before that. Many products are available online, especially from Asia, while a reduced number of products are available in local stores. Prices have rapidly come down from early products, but still vary widely, as does performance. The L-Prize-winning lamp is showing excellent performance with the expectation of long life. Dimming is also possible with many of the current LED products.

Less heat generated, less frequent need to purchase and install replacements.

Like CFLs, LED lamps are available in a variety of color temperatures. It isn't unusual to find some variance within the same color temperature between manufacturers. Consumers are just getting used to seeing lamps labeled with lumens for light output rather than shopping for wattage. To clarify, brightness is a description of the light output, which is measured in lumens, instead of watts. Although most manufacturers provide a comparison of the lumens (brightness) with the more traditional measurement of watts on the package, this is still a source of confusion to consumers. Because LEDs are naturally very directional, and CFLs and incandescents are omni-directional, a bulb shape LED may look like an incandescent lamp yet emit light in a very different distribution pattern than might usually be expected.

At this time, high-performing products are just meeting the light output of 75 watt incandescent lamps so they are not powerful enough to meet all current applications.

The potential disadvantages of LED A-lamps include:

• Current costs of LED products and performance, which are likely to be large barriers,
• Their appearance (especially if the lamp will be viewed directly) and how they fit in existing fixtures.
• Their additional weight , caused by the necessary thermal heat sink, may be too much for some fixtures.
• If used in enclosed fixtures, they may overheat and fail prematurely.
• Dimming performance at this time is highly variable and not possible with all products.
• Premature failure is likely if used with incompatible control systems.
• Disposal issues at end of life have yet to be resolved. Optimistically, lamps will not burn out for many years, but this question might become an issue. Ideally, the lamps would be recycled.  

A large number of products are only available online, frequently from companies either outside of the U.S. or with names that are unfamiliar to the general public. with some of the better products available through unfamiliar manufacturers, consumers may balk since familiarity can play a large role in consumer choices. Having ways for consumers to easily identify high-quality products with good reliability and customer service should increase their confidence and willingness to invest in this technology.

At this time LEDs are unable to replace 100 watt incandescent A-lamps that, according to the Energy Independence and Security Act, were to be phased out as of January 1, 2012.

The Federal Trade Commission’s new mandatory lighting label requirements will make some of the lamps’ performance information clear; however, this does not mean a specific product will be a good fit for a specific fixture and application. The Solid State Lighting Quality Advocates program, http://www1.eere.energy.gov/buildings/ssl/advocates.html, provides a voluntary Lighting Facts label for LEDs. These labels are submitted to the program, along with testing data describing some of the lamp’s performance and energy data, but does not include light distribution or lamp life at this time. ENERGY STAR, another voluntary program, has a qualified products list. As of February 2012, only Philips and GE had LED A-lamps listed. The USDOE and other organizations are working to provide consumer information about selecting lighting now that color choices and lumen output are reflected on labeling.

Halogen incandescent lamps may still be preferred by some consumers who are unwilling to use CFLs, but CFLs are the product to beat right now, in cost and light output. Achieving a satisfactory dimming performance and compatibility with existing controls is another plus for retrofit products. The other competition will come from dedicated LED luminaires, which typically achieve better performance than retrofit products. Some consumers will want to embrace the new styles of luminaires with that technology rather than keep their old fixtures.