Seven things you didn’t know about light bulbs (but should)
September 29, 2010 2 Comments
Seven things you didn’t know about light bulbs (but should)
By Brian Clark Howard
Posted Fri Sep 24, 2010 1:12pm PDT
Lighting is a significant expense for many of us, and it also affects how we work, play, and feel. The good news is that new advances in technology are providing more comfort, flexibility and efficiency, as we learned in our new book Green Lighting.
1. $1 invested in efficient lighting pays back $6 in energy savings
The standard incandescent bulb — what we typically think of as a "basic light bulb" — is a pretty inefficient piece of technology, wasting 90% to 98% of its electrical use as heat rather than useful light.
Much better are fluorescents, including the now-ubiquitous compact fluorescent lights (CFLs), which are roughly 75% more efficient for the same light output.
Try these 10 CFLs to fit any lamp.
By now, many people are aware of this fact, but few have taken a moment to actually calculate how much money they could save if they switched out their high-use bulbs to CFLs, as the commercials instruct us. In his book Wind Power for Dummies, Ian Woofenden calculates that a family using a 75-watt incandescent for six hours per day would spend about $54 a year on energy (at 32 cents per kWh), including the costs of replacement bulbs at 75 cents each.
If they replaced that instead with a 20-watt CFL, to produce the same amount of light, it would cost $14 a year to power. That fluorescent probably cost $6 but should last them four years at a use of six hours a day (without rapid switching), leading to a total expenditure of $15.50 per year over that time — $38.50 less per year than using incandescents. That’s a simple return on investment (ROI) of 642% per year.
That kind of ROI is hard to beat, which explains why heavy energy users, such as the managers of large commercial buildings, are switching to greener lighting in droves. Few technologies provide such a rapid payback on investment, and this blows away potential rivals like generating your own solar or wind power.
One caveat: As we point out in Green Lighting, lighting tends to make up only about 9% of the typical American home’s annual electricity use, so switching out your bulbs isn’t necessarily going to make you rich (though it is certainly great for the planet). For commercial facilities, however, lighting makes up an average of 38% of electricity use.
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2. Not all compact fluorescent bulbs last a long time
Some discount brands of compact fluorescents have disappointed consumers with short lives and relatively poor light quality. It is true that rapid switching is especially hard on them, so they often aren’t good candidates for closets. Cold temperatures also decrease their lifespans.
But to ensure quality, look for Energy Star-certified bulbs, since they must meet a range of criteria that go beyond energy efficiency. They must come with a two-year warranty, have a minimum rated lifespan of at least 6,000 hours and cannot emit an audible noise. They must turn on in less than one second and reach at least 80% of their output within three minutes. They can’t have more than five milligrams of mercury.
See these seven simple energy savers for the home.
3. Spent fluorescents shouldn’t be tossed in the trash
All fluorescent bulbs contain a small, and decreasing, amount of mercury, which is toxic. They actually result in less mercury released into the environment than incandescents, since those use so much more energy, much of which is generated from coal (which releases mercury). You can opt for low-mercury and safety CFLs, which have a protective outer dome to contain the contents in case of breakage.
If a fluorescent light breaks, ventilate the room for at least 15 minutes, keeping everyone away. Carefully scoop up all fragments with a piece of cardboard and use sticky tape to pick up any remaining residue. Then wipe the area with damp paper towels and place everything in a sealed container (glass is best). Take everything to your local hazardous waste dump, or find a location at lamprecycle.org.
Same goes for spent but unbroken CFLs — it is illegal to throw them in the trash in many places. Luckily, many retailers, such as Home Depot, are sponsoring collection spots as well. (Find more safety and cleanup tips in Green Lighting.)
Efficient lighting with LEDs in home of
Kim Lancaster. (Photo: Ashley Daigneault /
4. Installing dimmers could save more energy than changing bulbs
We interviewed some lighting experts who argued that if you are going to change one thing about your lighting, add some dimmers rather than switch to CFLs or LEDs.
More efficient bulbs certainly have benefits, but they do require some adjustment on the part of users, because they are not exactly the same as the incandescents we’re used to. Dimmers, on the other hand, require no learning curve, and provide added flexibility, comfort, and beauty.
"Even if you never use the dimmer you installed, it saves about four percent of the energy for that light," Michael Smith, a VP of dimmer maker Lutron, told us. This is because today’s electronic dimmers, which have dominated the market over recent years, have circuitry that optimizes efficiency. Any time you dim the lights down, you use less energy.
Many modern dimmers come with remote controls, and they can be readily tied in to whole-house systems, or programmed for security and convenience.
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5. Halogen bulbs are often the best choice for dimmers
When we started working on Green Lighting, we didn’t think too much of halogen bulbs, since they are only 10% to 40% more energy efficient than incandescents, and last only two to three times longer (versus more impressive CFLs and LEDs). But through our research and experimentation, we gained more appreciation for them as affordable and convenient stopgap options for the next few years, particularly when it comes to dimming.
Halogens are really incandescents with some added technology, and they dim like incandescents, in a very steady, smooth progression from 100% down to zero. Dimming them actually makes them last longer and saves energy, and the small size of halogens means they work great for track lighting, under cabinets and many other applications.
In contrast, normal CFLs cannot be dimmed. Those models offered with a dimmable ballast are more expensive but don’t perform as smoothly as what people are used to; they dim in stages and must be started over each time they are switched off. LEDs can be nicely dimmed with the proper circuitry but the market isn’t quite there for most practical applications.
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6. Standard overhead lighting is worse than alternatives
Most of us grew up with a single overhead light in each room (or a bank of lights in the case of classrooms and work spaces), since that’s the easiest for builders to install. But as interior designers know, a single overhead light is about the least flattering and least comfortable scheme there is. It tends to produce glare and harsh shadows that can be unpleasant and hurt productivity, since it can lead to eye strain.
As we learned from working on Green Lighting, it’s always advisable to have at least two sources of light for each space, and preferably not a central overhead. Architectural lighting can work wonders, and it’s not difficult or expensive to install.
Place small lights called coves on the tops of cabinets, shining up toward the ceiling, to make your kitchen look larger and more inviting. Place a valence on a wall, which shines light up and down, or use a sconce for elegance. If you’ve ever been to a Hollister clothing store, note the dramatic effects that can be achieved with spot lighting.
For bedrooms, soften the light with recessed downlights (ideally aimed at the foot of the bed), paired with a table lamp or directional lights at the head of the bed for reading. In offices, use diffusers with fluorescents to soften them and pair them with wall lights or ample daylighting. Brighten a basement by angling a few recessed ceiling lights against a lightly colored wall.
7. LEDs will become more and more common
Light emitting diodes (LEDs) have been around for decades, but they have really only recently become bright enough to work as general lighting. Their development is progressing rapidly, and their cost is dropping. Several major manufacturers (GE, Philips, Sylvania, Lemnis) are poised to offer "retrofit" bulbs that work in standard fixtures, replacing a 60-watt bulb for around 12 watts, for surprisingly competitive prices.
LEDs are widely seen as the future of lighting, and they are an exciting technology that is now being embraced by first adopters. However there will be some adjustment period.
Although they are getting closer to replacing other bright lights, they are still not as good at projecting illumination in 360 degrees. This is why they have historically been used more for directional lighting (as in flashlights and desk lamps), and they can cause shadowing.
LEDs also thus far produce cooler light, although quality is improving. In general, it’s a good idea to stay away from discount brands, which have had some early quality issues. Go for something with a decent warranty.
LEDs are expected to last for tens of thousands of hours, they are highly efficient, and they are resistant to water and mechanical shock. So there are many good reasons to support them now, as well as look forward to the future.
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