Which Is Greener: LED’s or CFL’s?

Author’s Note: For The Chicago Tribune, I answered a series of readers’ questions about living a greener, more sustainable life. This Trib reader wrote in to find out if LED lights were more efficient than CFL’s. Here’s what I dug up.

There’s no question that LED’s have a bright future, but Compact Fluorescent Lightbulbs (CFL’s) remain your most accessible, environmentally responsible lighting option for the home. Which is not to say the CFL is perfect. It is vastly more efficient than an incandescent bulb, but each CFL contains about 5 milligrams of environmentally harmful mercury-about equivalent to the size of a ballpoint pen’s tip, by ENERGY STAR’s calculations.

Not only are LED’s mercury-free, their long lifespan makes the Energizer Bunny seem like a quitter.Unlike traditional light sources-which throw off relatively consistent light and then, poof, burn out–LED’s get dimmer over time. Analysts recommend that the LED’s last rites be administered when they emit 70% of initial light output. Using that measurement, the Department of Energy, Energy Efficiency and Renewable Energy (DOE, EERE) calculates that the highest-quality white LED’s have a useful life of around 35,000 hours.

Some context: You could turn on a high-quality, white LED and forget about it for four years, when it would finally need replacing. Compare that to your garden-variety, 75-watt incandescent bulb, which throws out 1,000 lumens for about a buck, according to the DOE. That dollar bulb-which converts only about 5% of the electricity it consumes into light-will expire in about 1,000 hours. Comparable CFL’s-which are five times more efficient than incandescent bulbs-cost less than $5 and last 10,000 hours.

Today, you can see LED’s in traffic lights, signage and bridges, as well as in commercial and retail sectors. But these little-lights-that-could still lag behind the CFL in the race for dominance in energy efficient, residential lighting. One issue is that, although industry groups are working on it, standards for measuring and reporting LED performance factors don’t yet exist.

Until then, “manufacturers can claim just about anything,” says Peter Banwell, marketing manager of the U.S. Environmental Protection Agency’s (EPA) ENERGY STAR program. “Consumers need to be aware that some manufacturers have an incentive to make the most aggressive claim that they can.” If a manufacturer announces that their LED products live for 100,000 hours, for instance, they’re probably not using the 70% recommendation.

Wendy Reed of the EPA tells us: “In terms of regular screw-in bulbs and lamps/fixtures, the best environmental option is still CFL’s with the government’s ENERGY STAR designation. LED’s for this standard use just aren’t available for the average consumer, and the technology is still being worked on to get it there.” Because of the mercury in CFL’s, Reed emphasizes the importance of recycling those bulbs. (Visit www.earth911.com to find local recycling options.)

By summer, you’ll see the ENERGY STAR label on LED holiday string lights (for now, visit www.ledropelightsandmore.com or www.christmaslightsetc.com), and Reed rates LED night lights as the best, lowest energy option for that category (available at many retailers and hardware stores). But the shelves of big box outlets won’t bow under the weight of LED products until volume and demand drive prices down: White LED’s typically cost more than $50 per thousand lumens, according to the DOE.

Aside from cost, a few technological roadblocks impede the widespread adoption of LED’s for residential applications, including the LED’s lower light output. Lumens per watt (lpw) is a measure of how efficiently a light source converts electricity into useable light. While CFL’s produce at least 50 lpw (and incandescent bulbs 12-15 lpw), high-brightness LED’s sit in the middle, producing about 30-35 lpw, according to the DOE.

Many homeowners will also be unused to the LED’s “cooler” light quality. You can find LED products that replicate the “warm” light of incandescent bulbs, but these toastier versions sacrifice luminous efficacy, meaning that they throw off even less light than their cooler kin.

Another kink: LED’s can’t take the heat. Although they’re cool to the touch, they do warm up-and the hotter they get, the sooner they expire. That’s why “drop-in replacement” LED bulbs-the kind that fit into standard sockets, which tend to heat up-are less predictable performers than fixtures with heat sinks designed to accommodate LEDs specifically. The industry is working to perfect thermal management systems such that LED’s can be clustered together-thereby giving off more light-without shortening the lifespan.

Feeling like an early adopter? Right now, LED’s are best suited for accent, decorative and task lighting, in part because of the lower light output. That LED’s are extremely durable makes them appropriate for gardens and outdoor steps, too. But don’t expect LED’s to act like the lights you know. LED light is “directional.” It emits a focused beam of light, whereas traditional light sources are “omnidirectional,” throwing out light every which way.

In fact, the DOE reports that traditional light sources can waste 40-50% of total light output. That light is either reabsorbed in the fixture or squandered on areas that don’t need it (the ceiling comes to mind). High-quality LED task lighting-which shines a bright light on a focused spot-could help you cut back on overhead light significantly, particularly as the technology gets better and brighter.

Before you buy, consider a word of caution from the DOE: Beware the LED products marketed as “energy efficient” when in fact they throw off very little light. Though a bulb that consumes only a few watts of power might seem like a good choice, it’s hardly efficient if you burn out your overheads to compensate.

One way around that is to try them out by visiting reputable manufacturers or showrooms (we’ve listed a few below). And keep in mind that if a price point seems too good to be true, it probably is. “The early, very well-made products have a lot of engineering behind them,” says Banwell, “and you just can’t do that on the cheap.”

We like the way Greg Kay, president of high-end lighting showroom Lightology, puts it: “There are no bad lights. Only bad applications.” HE means that lighting is not one-size-fits-all, so it’s critical that you determine the best source for the use you have in mind. Do you want a diffuse light-the kind you get from traditional sources? Or will a precise beam of less intense light suit your needs? Talk with a lighting expert about your needs, advises Kay.

For LED enthusiasts, it’s only a matter of time until this technology enters the mainstream. Cool to the touch and tiny enough to be embedded into walls and ceilings, they could even revolutionize the way we think about lighting. One day, for instance, you might come home to turn on your ceiling.

Whether it’s radical or incremental, change is inevitable-even overdue. “Why are we still using a light bulb that was, essentially, invented in 1879?” Banwell says. “There aren’t that many technologies around today that were used when people rode horses to work. We’re entering an era where there’s significant movement underway to change the way we light our homes.”

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