Confused about Your Home Lighting? – LED, CFL and Incandescent Compared

Switch 3-Way LED Light Bulb

Switch 3-Way LED Light Bulb

Incandescent lighting was the most effective way to produce light for more than a century.  Now, there are new alternatives to light your home. Here’s a quick guide to understand the differences between LED light bulbs, compact fluorescent bulbs (CFLs) and traditional incandescent bulbs.  First, let’s start off with the basics:

Incandescent Light Bulbs

Incandescent light bulbs remain unchanged since Edison invented the light bulb in 1879.  A traditional light bulb uses electricity to light a tungsten filament that gives off light when it heats up inside of a bulb filled with an inert gas.  This is a very inefficient way to produce light since incandescent bulbs give off most of their energy (as much as 80 or 90 %) as heat rather than light.

In 2007, US legislators imposed strict energy efficient guidelines impacting 100W incandescent light bulbs in the Energy Independence and Security Act of 2007.  The 100 Watt incandescent bulb was officially phased out in the US in January 2012.  California was slightly ahead with a date of January 1, 2011.  The 75 Watt bulb effective date was January 1, 2013 (California, 1/1/2012). The 60 Watt and 40 Watt bulb effective dates for phase out are January 1, 2014 (California, 1/1/2013).


A descendant of traditional fluorescent lights, CFLs contain argon and mercury vapor housed within that spiral-shaped tube. The bulbs rely on an integrated ballast to produce an electric current that passes through the mixture of gasses, exciting the gas molecules that produce the light.  The time for the ballast to produce the electrical current causes that typical CFL delay when it is turned on.  CFLs use 20-30% less energy than the typical incandescent and last 8 to 15 times longer.  Of course, they do contain mercury, so cleaning up after breaking them and disposing of CFLs after they burn out becomes problematic.  Here’s a link to how to dispose of CFLs safely for you and the environment.

LED light bulbs

Unlike traditional incandescent bulbs, LED light bulbs generate light using a small “package” of several LEDs in a light bulb.  LED light bulbs are more efficient since they use a semiconductor to emit light or photons when electricity is passed through it.  LED light bulbs give of more than 80% of the energy used as light. The good news is that LED light bulbs can cut household energy use by as much as 80% and have a lifetime of 25,000 hours or more.

How do they stack up?

Here’s a graphical look at how each stacks up comparing Cree and Philips LED light bulbs to typical GE and Philips CFLs.  The information was developed using Home Depot’s web site using the “Lighting Facts” package labeling required by the US government.  You can link to the DOE’s web page about the labels for more info.

What does Lumens/Watt mean?   This is a measure of how well the light source produces light.  The higher the number, the better your light source is at producing light.

What’s the Color Rendition Index? The CRI is a measure of the color of the light and the way the light affects objects.  We noted the type of color of light: warm, soft or bright in this field.

For Further Reading

US DOE, Solid State Lighting Basics,



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About Beth

It seems like LEDs are in everything these days – backlighting everything from your mobile phone, Apple iPad and flat screen HDTV to traffic lights, light bulbs and even the kitchen sink. But, making LEDs is a complex process that begins with the creation of sapphire. Not the pretty blue gemstone, but large commercial crystals that can weigh as much as 400 lbs. Once these large sapphire crystals are grown into boules and cooled, they’re cut into cores, cut further into flat circular wafers, polished and then used to grow LEDs. About 85 percent of HB-LEDs (high brightness) are grown on sapphire. There’s not that much information out there about the process. This blog is meant to shed some light (excuse the pun) on sapphire, LEDs and the industry that is devoted to making our lives just a little brighter. In the months ahead, we’ll tackle some topics that will help you understand a little more about sapphire and LED industry. Here’s a sample of what we’ll cover in the coming months: • Growing sapphire • For a wafer, size matters • Quality - When sapphire wafers go bad • LED light bulbs • Market & myths • Interviews with industry shining stars • Reports from industry events • Current events in perspective Please join us each week to learn more about sapphire and the LED market. We look forward to seeing you.

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