LED vs CFL Bulbs: Which is More Energy Efficient?

  • May 7, 2018

 

Energy Efficiency

The wholesale switch from incandescent light bulbs, which were discontinued for wattage above 40 watts in 2014, to the more energy-efficient compact fluorescent lamp (CFL) bulbs and light emitting diode (LED) bulbs have been evolving for years. A lot of confusion still exists, however, about these bulbs, starting with which is which. Is the long light bulb the CFL bulb and the LED the curly light bulb? Or is it the other way around — CFL is the curly light bulb and LED is the long light bulb? And that’s before we even analyze which one is more energy efficient!

In short form, here are the answers: CFL is the curly light bulb and LED is the long light bulb. And, in the CFL vs LED battle for energy efficiency, the LED light benefits make it a winner, hands down. Here’s what you need to know.

CFL vs LED Bulbs

To understand LED light benefits, it’s important to understand the difference between the two bulbs. LED light bulbs produce light when an electrical current passes through them. In CFL bulbs an electric current flows between electrodes at each end of a gas-filled tube. The reaction creates ultraviolet light and heat, which is then changed into light when it hits a phosphor coating on the bulb’s interior. This process takes anywhere from 30 seconds to 3 minutes to complete, according to ENERGY STAR®, which is why it can seem as if your CFL light takes a while to be fully lit.

CFLs use 25-35% of the energy used by incandescent bulbs, but if you really want to make the biggest environmental impact on the environment, choosing LEDs is the way to go. Residential LEDs, especially those rated by ENERGY STAR, use 75% less energy and last 25 times longer than incandescent lighting. Energy.gov notes that by 2027 widespread use of LEDs could save about 348 TWh of electricity, the equivalent of annual electrical output of 44 electric power plants (1000 megawatts each). It’s also a total savings of more than $30 billion at today’s electricity prices.

Here are some other differences to keep in mind when examining CFL vs LED bulbs:

  • LEDs emit very little heat. In contrast, incandescent bulbs release 90% of their energy as heat, CFLs release about 80% of their energy as heat, according to Energy.gov.
  • Another LED light benefit is that LEDs, because they emit light in a specific direction, do not need diffusers or reflectors that trap lights. This helps increase LED efficiency for uses such as downlights (recessed downlights are common in residential kitchens, hallways and bathrooms) or task lighting.
  • The Department of Energy estimates that there are at least 500 million downlights in U.S. homes, with more than 20 million sold each year. The DOE estimates that both CFL and LED lighting could decrease downlight wattage by at least 75%.
  • The same LED string of holiday lights could still be in use 40 holiday seasons from now, according to Energy.gov.

This chart shows the difference in costs between CFL vs LED bulbs:

Source:http://www.nrdc.org/energy/lightbulbs/files/lightbulbguide.pdf

 

The difference between lumens and watts

Something else consumers need to understand while analyzing CFL vs LED bulbs is the difference between lumens and watts. Consumers are used to buying light bulbs based on watts, or how much energy they consume. It didn’t matter how much light (lumens) they provided. Now, as a way to differentiate LED vs CFL bulbs, manufacturers are classifying the new energy-efficient bulbs by their lumens. You are buying your bulb based on the amount of light you want rather than the energy used by the bulb.

Admittedly, it can be confusing. Here’s the basic point to keep in mind: More lumens equals more brightness. But exactly how many lumens is equivalent to what was once, say, a 60-watt bulb? Here’s a breakdown to give you the basic new LED vs CFL light bulb math:

  • To replace a 100-watt incandescent bulb, choose a bulb with about 1600 lumens.
  • To replace a 75W bulb, choose a bulb with about 1100 lumens.
  • To replace a 60W bulb, choose a bulb with about 800 lumens.
  • To replace a 40W bulb, choose a bulb with about 450 lumens.

Source:http://energy.gov/sites/prod/files/lumens_placard-black.pdf

 

The reality is that while switching light bulbs from CFL to LED can seem like a small step toward energy efficiency, the result nationwide can be a win-win for everyone: potentially lower energy costs in your home and in the U.S. as a whole.

 

 

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