LED vs. CF vs. Incandescent

Which has the smallest total life-cycle impact?

Inside this Article

GE LED bulb
General Electric brand LED bulb
GE LED bulb

Number-nerds will rejoice in the graphs and data-crunching of an August 2012 U.S. Department of Energy (DOE) study—Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products—which assessed the results of 10 other studies and compared the total life-cycle impacts of LED, CF, and incandescent lamps. The results weren’t surprising—spoiler alert! LEDs came out on top—but the slim margin between the top two efficiency contenders was.

The three-part study looked at the energy required for lamp use, manufacturing, transport, and disposal. Since the lumen output and lifetime for each lamp type are not equivalent, the study measured each lamp’s energy use with a “functional unit” of 20 million lumen-hours—the estimated service life of a single 12.5 W LED lamp (60 W incandescent replacement) over its lifetime. An incandescent or CF lamp provides less lighting service than the functional unit value, so in order to make an apples-to-apples comparison, life-cycle energy estimates are multiplied by the number of lamps needed to reach this equivalence.

According to the analysis, the “use” phase of incandescent, CF, and LED lamps is the most energy-intensive portion, accounting for approximately 90% of a lamp’s total life-cycle energy. The manufacturing and transport phases follow, respectively—with energy use due to transportation representing less than 1% of life-cycle energy for all lamp types. The uncertainty with LED life-cycle assessment centers on the manufacturing of the LED package (including substrate production, LED die fabrication, and the LED assembly). Low estimates indicate that the LED package contributes to 0.10% of life-cycle energy use, while high estimates show it could be as much as 27%. The average indicates that LED package manufacturing is likely at about 6.6% of total life-cycle energy use.

The analysis concluded that LED replacements and CF lamps are similar in their life-cycle energy consumption, with the difference largely determined by the manufacturing aspect. During their lifetime, LEDs and CF lamps consume 3,890 and 3,950 megajoules (MJ) per 20 million lumen-hours, compared to an incandescent lamp’s energy consumption at 15,100 MJ per functional unit. The energy used to manufacture can be from four (CFs) to eight (LEDs) times as much as an incandescent.

By 2015, if LED lamps meet performance targets, their life-cycle energy use is expected to decrease by approximately 50%, which will give them a big efficiency gain over both CF and incandescent lamps. Improvements to current manufacturing methods and procedures are expected to reduce the manufacturing energy use, but the biggest gain will likely be due to an increase in LED lamp efficiency, resulting in fewer watts required to provide the same amount of lumens.

By 2030, the DOE forecasts that LED lighting will represent 74% of lumen-hour sales in the U.S. general illumination market. From 2010 to 2030, the cumulative energy savings is estimated to be 2,700 terawatt-hours, which at 2010 energy prices and electricity-generation-mix conditions represents approximately $250 billion in savings and a greenhouse-gas emission reduction of roughly 1,800 million metric tons of carbon dioxide.

The environmental impact of the incandescent lamp’s energy use were markedly more significant than for CF and LED lamps because of its low efficiency. The CF lamp is slightly more harmful than the 2012 LED lamp against all but one criterion: hazardous waste sent to the landfill. The energy and environmental impact of the manufacturing of the aluminum heat sink used in LEDs causes the impacts to be slightly greater for the LED than for the CF. The study notes that heat sinks should diminish in size for succeeding generations of LED lamps as efficiency gains are made. Environmental impacts of a 2017 LED, for example, are predicted to be about 50% lower than the 2012 LED and 70% lower than the CF.

A variety of LED, CF, and incandescent lamps—a total of 22 samples, representing 11 different models—were tested to determine whether any of 17 elements were present at levels exceeding California or federal regulatory thresholds for hazardous waste. Most of the lamps were found to be well above the California threshold for copper, regardless of technology, and some approached or exceeded the threshold for nickel. The selected models were generally found to be below thresholds for federal regulation. The study noted that the greatest sources of hazardous waste were the metal screw bases, drivers, ballasts, and wires or filaments—the diodes themselves generally did not cause LED lamps to exceed thresholds

—Compiled by Kelly Davidson

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Comments (10)

Kurt Housh's picture

T-5 HO FL tubes are still more efficient if they can be integrated into the lighting design. I use them for under cabinet lighting, wall and ceiling washes, and in the garage.

KathieLedesma's picture

This is very informative. Thank you for this article of yours. God bless you :)

Frederick Hillenbrand's picture

We built a 100% LED home put in service in December 2011 (with a very few intentionally selected CFLs and incandescent lamps in chandeliers). We bought the LEDs drop shipped direct from the manufacturer in China since we were putting in so many. All LEDs are working as installed including; dimmed and undimmed, indoor and outdoor rated strip lighting, round flat panels (in lieu of "can" lights) and spot lights. I love my LEDs.

Debbie Crutcher's picture

We design and install off grid and RV power systems. Some of our customers have told me their LED lights are failing after 1-3 years. I don't know if they bought quality lights or not so don't draw any conclusions from my anecdotal observations.

Comparing the cost of LED light to the cost of CFL's and producing the extra power needed operate them, I find that LED's have no benefit. Add to that the peculiarity of light spectrum and poor distribution characteristics, I conclude that LED's are not a viable option to offer my customers.

Larry Crutcher
Starlight Solar Power Systems

Christopher Guy's picture

I am surprised, I would have thought that the cost of producing additional power would dwarf the cost difference. I have noticed that in the past year LEDs have become more powerful and thus more efficient.

Modern LEDs can be purchased in 3000K warm white, is dimmable, doesn't flicker or make noise and is instant on. I switched to CF 5 years ago and I can say from experience these lights fail when used in a room that has the lights turned on/off all the time (e.g. washroom), when upside down or just whenever. I have a replaced every CF at least once and some 3 or 4 times in just 5 years. In 2 years of LEDs, mostly outdoors, but some indoors, and not one has failed to date. Another plus for LEDs is that they are much more tolerant of out of spec voltages.

The latest LED from Philips uses 11 watts for 900 lumens and has a good warm white tone. The price is crazy high, but with sales and rebates from the utility the price drops from out of this world expensive to just very high.

You might want to take another look at the new LEDs.

Christopher Guy's picture


carl Johnson's picture

These laboratory test results are often for ideal conditions. Quoted life span of these devices also don't account for the real life conditions they face. These include the quality of power supplied to them - fluctuations in voltage, power failures, brown outs, surges or even atmospheric changes (temperature, humidity/moisture, sunlight exposure / solar flares, etc.) which can wreak havoc on the sensitive electronics in them. I've seen all types of lighting devices which get direct sunlight exposure in hot summer months of August in the deep South of the US fail very quickly.

Christopher Guy's picture

I have been using CFL bulbs for almost 10 years now and my experience has been that the bulbs are burning out long before their rated life. Frequent on/off cycles seem to be cause.

I have changed over all my outdoor lights to LED (it is -30 today) and the LEDs are working well where as CFL would be really dim.

I'm waiting for a price drop before switching over all my indoor lights, but being dimmable ans having a much wider voltage range means I might start the change sooner.

Chris, Montfort Quebec, Canada.

Michael Welch's picture

I bought a case of six Osram bulbs about 1991 for my off-grid home ($75). All but 1 are still working as if new. Since then, I've bought several more, but always the highest quality I could find based on reputation. They've lasted pretty well too, with some exception.

It's really too bad the way our consumer society has taken to cheaply (poorly) made stuff to save a few bucks.

Brian Sumner's picture

I did this as well, but my first experimental purchases were VERY cheap China CFL's. These are still working ten years later! I have both 60 and 100W equivalents, and one 150w on desk. Go figure.

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