CFL vs. LED Lights: Which is the Energy Efficient Light Bulb?

Image: light bulbs in a cafe. Topic: CFLs vs. LEDs: The Better Light Bulbs

Your home is a place of warmth and comfort, and your lighting has a lot to do with that. Green America recommends choosing energy efficient light bulbs, which are good for your home, your wallet, and the planet.

Energy experts agree the incandescent bulb is rapidly becoming a thing of the past. In fact, in 2007, Congress passed the Energy Independence and Security Act, which requires all light bulbs sold on the market to have a 30% increase in efficiency over today’s standard incandescent bulbs. Store shelves once stocked with only incandescent bulbs are now full of CFL and LED lights.

In the past decade, many consumers have shifted to using compact fluorescent light bulbs (CFLs) or light-emitting diode bulbs (LEDs). Lighting can account for 15% of a home’s energy costs, and switching saves the average home $225 on the monthly energy bill.

The US Department of Energy (DOE) approved the phase out of incandescent bulbs in favor of LEDs and compact fluorescent lighting (CFLs) in 2022. The DOE estimates that the new rule will reduce US carbon emissions by 222 million metric tons over the next 30 years. That's roughly equivalent to the emissions generated by 28 million homes in one year!

Why Abandon Your Incandescents?

Invented by Thomas Edison in last quarter of the 19th century, modern incandescent electric light bulbs have been lighting much of the world for more than 100 years. Incandescent bulbs are lit by heating a wire tungsten filament until it begins to glow. Because approximately 90% of the energy generated in these bulbs is heat instead of light, they are extremely inefficient. The average incandescent bulb has a lifespan of about 1,500 hours—a fraction of what you can get from a CFL or LED bulb.

Halogen lights are a more efficient form of incandescent lighting because they last longer; however, they get hotter than regular incandescent bulbs and pose fire and burn hazards.

For nearly every incandescent bulb still in use today, there’s a CFL or LED light bulb that can replace it—saving energy and curbing carbon emissions. If you still have incandescents at work or home, it’s time to send them back to the Dark Ages.

CFLs: An Improvement on Light Bulbs

CFLs (and fluorescent tube lights) are lit by an electric current that is sent through a tube containing argon and a small of amount of mercury gases. This in turn generates an invisible ultraviolet light, which then stimulates a fluorescent coating on the inside of the tube, producing visible light.

Pros of CFLS

  • Longevity—With an average lifespan of approximately 10,000 to 15,000 hours, a CFL bulb lasts about ten times longer than an incandescent bulb—which means they need to be replaced less often, making them convenient for those hard-to-reach light fixtures and lamps.
  • Efficiency—“CFLs are about four times more efficient than the equivalent wattage of incandescent bulbs,” says Naomi Miller, the senior lighting engineer at the Pacific Northwest National Laboratory in Portland, OR. “So if you take the wattage of the CFL and multiply it by four, that equals the incandescent bulb you would replace. So, for example, a 15W CFL is roughly equivalent in light output to a 60W incandescent bulb.” According to the Environmental Protection Agency (EPA), if every household in America replaced just one incandescent bulb with a CFL, the energy saved would be enough to light 3 million homes and prevent greenhouse gas emissions from the equivalent of 800,000 cars.
  • Price—CFLs have dropped dramatically in price since they were first introduced to the market in the 1980s. They still cost a little more than incandescents; however, they will pay for themselves after a year or two of use. Because they last so much longer than incandescents, you will continue to see savings on your energy bills throughout the life of the bulb.

Cons of CFLS

  • Mercury concerns—Many people are concerned about the mercury in CFLs, and with good cause: mercury is a neurotoxicant. The amount in a CFL bulb, however, is smaller than the tip of a pencil. Increased use of CFL bulbs instead of incandescents actually reduces the amount of mercury released into the atmosphere, since the main source of mercury emissions are smokestacks from fossil fuel burning power plants, according to the EPA. CFLs pose little risk to your family if they break, but proper clean-up is important.
  • Some usage limitations—CFLs are not dimmable, and they are not efficient in recessed lighting, where they waste about half of the energy they produce. To maximize their efficiency, avoid exposing them to extreme temperatures.

Best uses:

CFLs were a placeholder for LED lights, because LEDs are even more efficient. LED lights are readily available in both brick and mortar stores and online and come in all shapes and sizes.

If you adopted CFLs as replacements for incandescent bulbs go ahead and use them until they stop working; just make sure they are disposed of properly at the end of their life cycle.

LED Lights: The Energy Efficient Light Bulb

LEDs were first introduced to the market in 1962. They work by the movement of electrons through a semiconductor material. Initially, LEDs only emitted red light, so their uses were limited to indicator lights and lab equipment. Now, however, they are available in the visible, ultra-violet, and infrared spectrums, which means they now have a much wider variety of uses, including inside your home.

Pros OF LEDs

  • Longevity—With a lifespan of approximately 25,000–35,000 hours, an LED bulb lasts 2 to 4 times longer than a CFL, and 25 to 35 times longer than a standard incandescent bulb.
  • Efficiency—While incandescent bulbs and CFLs generate most of their energy in heat, LEDs are cool to the touch—which translates into less wasted energy. It also means your air conditioner won’t have to run as high in hot weather. LEDs are more efficient than even CFLs: A 16.5-watt LED bulb is equivalent to a 20-watt CFL and a 75-watt incandescent. A report from the DOE states that LED adoption saved consumers $14.7 billion in 2018.
  • Other benefits—LEDs have other advantages over incandescent lights, including a smaller size and greater durability and reliability. Unlike CFLs, LEDs can also withstand extreme temperatures, and they do not contain mercury.

Cons of LEDS

  • Color quality—Some users may find LED light a bit stark as compared to incandescents. “LEDs are most efficient when they emit a blue-white color, but many homeowners prefer a warmer (yellower) color of light,” notes Naomi Miller. When selecting an LED bulb, look for a ‘Lighting Facts’ label on the box, she says. It includes a spectrum bar that will indicate whether you’ll get a yellowish or bluish light. There are more and more LEDs with warmer colors available, and for people worried about LED light impacting their sleep, there are LEDs that are specifically designed for nighttime use that do not emit blue spectrum color.
  • Expense—LED lights are more expensive up front, but provide substantial energy savings over time.  So, you may want to swap out your light bulbs over time, rather than changing all the bulbs in your house at once.

Best uses:

LED lights are now available for all uses—overhead and recessed lighting, lamps, and fixtures. They also make great indoor and outdoor holiday lights. 

The Bottom Line

LEDs are your best bet for an energy efficient light bulb, reducing your utility bill, eliminating toxic mercury, and protecting the planet.

Updated September 2022