Fluorescent lighting: the household market

Fluorescent lamps were introduced to U.S. industrial markets by GE in 1938 to provide efficient lighting. They used about a third the electricity used by incandescent bulbs providing the same amounts of light and could last several times as long. At first, reliability was marginal, but improvements during the World War II years led to rapid expansion of use afterward. In 1950, fluorescents provided about half of U.S. commercial lighting.

At four and eight feet long, with 1-1/2 inch diameter, early fluorescents were too big for household uses, and green-tinged light proved unacceptable. Shorter and thinner tubes, circular tubes and better-balanced light won some household use in the 1950s–including kitchen, laundry, garage and undercounter lighting. However, the lamps could not be used in common household fixtures.

Slow growth: High-efficiency household lighting grew slowly for about 50 years. After the Arab Oil Embargo of 1973, at a time of rapidly rising electricity prices, small fluorescent lamps became available. They had thin, U-shaped “biax” tubes about 7 to 10 inches long with contact pins, required separate transformers, could be found only at electrical supply houses and cost about $30 in current value. With expensive electricity, however, they could save at least twice their prices over average lifetimes, earning some uses for stairs and hallways.

Starting in 1980, what we now call “compact fluorescent” lamps became available from Sylvania in the U.S., Philips in the Netherlands and Osram in Germany. These had two or three shorter U-shaped tubes protruding from a base containing a transformer and providing a screw contact matching conventional lamp sockets. They would fit some fixtures made for incandescent lamps, provided there was enough room. Lengths of tubes and diameters of bases were too much for others.

Innovations: By the mid-1990s, three innovations had transformed the market. Integrated electronics provided rapid starting, low-temperature operation and little flicker. Improved phosphors provided “warm white” light. Small bases and spiral tubes allowed low-power units, up to about 15 W, to fit most fixtures designed for incandescent bulbs. The lighting efficiencies of low-power units grew to over four times those of the incandescent bulbs replaced, and the typical rated lifetimes reached about ten times those of the incandescents.

Financial value from small and compact fluorescents had always been satisfactory, but most people resisted prices ten to forty times those of incandescent bulbs, ignoring the long-term savings. Through the 1980s, few grocery and hardware stores sold compact fluorescents. The growth of home improvement chains during the 1990s made a difference. Home Depot, Lowe’s, Menards and others stocked the lamps in depth and offered them at discount prices, often no more than five times incandescent prices.

Maturity and acceptance: In the late 1990s, grocery and hardware stores also began to stock compact fluorescents near their displays of incandescent bulbs, reinforcing awareness of and confidence in the products. Two decades after they had been introduced, sales of compact fluorescents accelerated. In its most recent report, the U.S. Department of Energy found a sales ratio of one compact fluorescent lamp to about five incandescents. Since compact fluorescents last about ten times as long, they may be producing about two-thirds of household lighting in the U.S.

Excitement about newer light-emitting diode (LED) lamps trimmed interest in compact fluorescents. However, current LED lamps are around 20 years behind in product maturity. Premature failure remains a problem. Shapes, light quality and power ratings have yet to be standardized for LED lamps. Most units are too large to fit in common fixtures. Prices remain high. Vendors and enthusiasts try to compare LED lamps with incandescents, but that game is over. Fluorescent lamps are now the U.S. standard household lighting.

Competition: Comparisons with compact fluorescents showed previous LED lamps as marginal or inferior, except where high costs of lamp replacement provided an advantage to long lifetimes–notably roads, bridges and high ceilings. Despite claims, LED lamps did not offer any clear environmental advantage. Instead of hazardous mercury, they contain hazardous arsenic and gallium. Both lamp types include electronic circuits, and they need controlled disposal.

In 2014, comparisons changed with the introduction of a new generation of low-cost, high-efficiency LED lamps, comparable in many ways to compact fluorescents. Lamps most common in households have outputs of about 900 lumens and color temperatures of about 2,700 K, similar to 60 W incandescents. Home Depot began to offer an 800-lumen LED lamp from Cree at about $10.00 each, competing with its Ecosmart 900-lumen compact fluorescent at about $1.50 each.

Better mousetrap: The compact fluorescent cited has a rated efficiency of about 64 lumens per watt and rated lifetime of 10,000 hours, while the LED lamp cited has a rated efficiency of about 84 lumens per watt and rated lifetime of 25,000 hours. Relatively high Massachusetts electricity rates lead to the recovery of the cost difference from electricity savings over about 4 years, when lamps are used about 3 hours a day. Savings will continue to build over a lifetime of about 25 years for the LED lamp.

Factoring in historical trends of Massachusetts electricity prices over the most recent 23 years, from federal data, a set of 9 LED lamps, equal in rated output to a set of 8 compact fluorescent lamps, would save about one dollar per year per LED lamp over 25 years of rated life at 1,000 hours per year–combining lamp and electricity costs and adjusting to present values by a 6 percent per year discount factor.

If favorable efficiencies and pricing can be maintained with high quality, replacement of compact fluorescent by LED lamps now looks likely. A remaining disadvantage of many current household LED lamps is unsatisfactory guarantees. Guarantees on compact fluorescents began at a year or less, but the one cited currently has a 9-year guarantee.

Growing pains: The LED lamp cited currently has a guarantee from the manufacturer of only 3 years–approximately its rated life when turned on all the time. Many early failures were reported on-line this spring–suggesting quality-control problems. It might be best to wait a year or two until issues with this generation of LED lamps are resolved and similarly efficient lamps are available from several manufacturers.

– Craig Bolon, Brookline, MA, October 10, 2014

Energy Star compact fluorescent market profile, U.S. Department of Energy, 2010

Compact fluorescent lamp market effects, California Public Utilities Commission, 2009

L.J. Sandahl, et al., Compact fluorescent lighting in America, U.S. Department of Energy, 2006

New generation of compact fluorescent lamps, Environmental Building News, 1994

Ashok J. Gadgil and Arthur H. Rosenfeld, Conserving energy with compact fluorescent lamps, Lawrence Berkeley National Laboratory, 1990

Eric A. Taub, Industry looks to LED bulbs for the home, New York Times, May 12, 2009

Solid-state lighting, U.S. Department of Energy, 2014

Craig Bolon, Full operating cost comparison: compact fluorescent versus LED lamps, October, 2014

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