Lighten Up With Energy-Efficient Light Bulbs

By choosing to replace incandescent bulbs with more energy-efficient light bulbs, such as LED lights and CFL bulbs, you can be guaranteed to have effective light with less overall energy use.
By Sean Groom
January 16, 2011
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LED Light: Small, powerful, and efficient. Now that they produce white light appropriate for residential settings, LEDs grouped together in a bulb pack enough punch that this 8w LED from Nexxus can replace a 75-watt PAR30 incandescent bulb. 

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Energy efficiency begins at home, which can often be improved easily with the right knowledge, tools and materials. This excerpt comes from The Energy-Smart House (Taunton Press, 2011) is a collection of articles on how to reduce the amount of energy your home uses, from installing energy-efficient light bulbs to insulation and windows. The following is adapted from Part 5, “Lighting and Appliances.”  

Although still a relatively small slice of the incandescent-dominated lighting market, energy-efficient compact fluorescents (CFLs) and light-emitting diodes (LEDs) have gained traction over the past few years, thanks to green-building programs and some progressive local energy codes.  

Be sure and look at the Efficacy at a Glance and Sources boxes (in the Image Gallery) for even more information on energy-efficient light bulbs and where to buy them. 

CFLs Come of Age 

CFLs were introduced in the early 1990s, but they weren’t ready for prime time. Early CFLs produced harsh blue light, hummed, and flickered, making a poor first impression. Today’s CFLs, however, produce light at around 2,700 degrees Kelvin (the measurement of light hue), mimicking the warm, amber-hued light of incandescent bulbs. Also, the old magnetic ballasts have been replaced with quiet electronic ballasts that don’t flicker. 

CFLs are dramatically more efficient than incandescent light bulbs, using between 50 percent and 80 percent less energy, and they last for about 10,000 hours, nearly 10 times longer than incandescents. They also cost dramatically more. However, replacing one 50 cents, 75-watt incandescent bulb with a $3.50, 19-watt CFL saves 563 kwh of electricity over the life of the bulb. That comes to about $75 in savings, depending on the cost of electricity where you live.  

On the downside, a typical CFL contains somewhere between 4 mg and 5 mg of mercury. Critics of CFLs highlight the health and environmental hazards of mercury, and special precautions should be taken if the bulbs break in your house. Proponents argue that the mercury in a CFL is far less than the amount of mercury emissions that would be released from a coal-fired power plant if you were using an incandescent bulb. Regardless, when a CFL burns out, it must be recycled so that the mercury doesn’t end up polluting the environment. Some retailers of CFLs, including Ikea and The Home Depot, offer CFL recycling. To find other recycling locations, visit the EPA website.

LEDs Are the Future

LEDs are a Silicon Valley technology, manufactured in a clean room, just like a computer chip. Electrical current runs through the 1-square-milimeter chip, exciting the electrons and creating light. A small bulblike cover focuses the light. LEDs can’t actually produce white light; white light must be created either by combining colors or by using a phosphor coating inside the bulb.  

The lighting industry is betting heavily on forging ahead with significant advances in white-light LED technology in the next few years. Many of today’s LEDs, however, already perform well when used in the appropriate location.  

Manufacturers describe LEDs as cool-operating lamps. While it’s true that the lit end of an LED is cool to the touch, the semiconductors do produce heat. And just as computer chips require cooling to perform properly, LEDs need thermal management. The heat sink, usually a number of large aluminum fins located near the base of the lamp, is a critical component of an LED.   

LEDs are already more efficient than incandescent bulbs, producing approximately 60 to 70 lumens per watt, and manufacturers expect efficiency to surpass that of CFLs soon. Their 50,000-hour average life span translates into 34 years when used four hours a day. There are other advantages to LEDs’ solid-state engineering as well: They are immune to vibration, and their performance improves in cold temperatures, making them ideal for outdoor applications.  

Cost is currently the biggest drawback to LEDs. A screw-in LED replacement for a recessed light costs about $120, but remember that LEDs are the lighting equivalent of a computer chip: Just as Intel founder Gordon Moore predicted that chip capacity would double every two years (Moore’s Law), Haitz’s Law (named for scientist Roland Haitz) states that every decade, LED prices will fall by a factor of 10 while performance will increase by a factor of 20. 

Still, a word of caution is appropriate. There are some well-engineered LED bulbs and fixtures on the market, but with so many manufacturers jumping on the band wagon, there are plenty of LEDs with harsh light and poor switching and dimming response. It’s a good idea to evaluate these products carefully before purchasing. 

Match the Light to the Job

Both CFLs and LEDs are available with screw-in bases as replacement bulbs for existing fixtures, but if you are building a new home or remodeling, you might consider fixtures dedicated to one technology or the other. Dedicated fixtures can lengthen the lifespan of the bulb and maximize its strengths. Both CFLs and LEDs play a role in providing ambient, accent, task, and decorative lighting, the four layers that create a well-lit room. But CFLs and LEDs aren’t necessarily interchangeable. That’s largely because CFLs are a multidirectional light source and LEDs are a point source. 

Because they are multidirectional and produce large amounts of diffuse light, CFLs work well for ambient, task, and decorative lighting. They can be used nearly everywhere that incandescent bulbs are used, particularly in table lamps and in shielded sconces, where the fabric or glass adds color to the light. In the bathroom, when they’re used behind opaque glass, CFLs do a great job of lighting your face. In kitchens, in laundry rooms, and in offices, CFLs produce bright-enough ambient light to illuminate worksurfaces.

CFLs are not appropriate everywhere, however. Locations where lights are switched on and off quickly — say an entry hall or a coat closet — are not ideal because CFLs need time to attain their full brightness and because short-cycle switching reduces the bulbs’ lifespan. Also, if you’re using a CFL bulb in an outdoor fixture, make sure that it’s labeled for outside use, which means that the ballast will work in cold temperatures.

Task and Accent Lighting Require Focused Light 

LEDs produce a focused beam of light. Although their relatively small output means they can’t throw light as far as some incandescents, there are plenty of circumstances where they work well as task lights. And they’re ideal for accent lights because they don’t produce UV-light that damages paintings and fabrics. Because LEDs are small and easily produced as pucks or strip lighting, they are ideal for undercabinet illumination or as accent lights hidden in coves or inside cabinets, where small size and low heat output are important. 

Glare can be a concern with bright LED fixtures, especially recessed lights. San Francisco Bay Area lighting designer Eric Johnson recommends using a diffuser with recessed cans or, at the very least, recessing the bulb as deep into the fixture as possible.

Lightolier’s Calculite is a lensed fixture that uses a diffuser to create white light. Instead of coating the LED bulbs with phosphor, the phosphor is applied to the diffuser.  

Under the first approach, variations in the amount of phosphor coating on each diode affect the overall color of the light. When you have multiple downlights in a room, this can result in variations in the light from the different fixtures. It’s easier to apply an even, consistent phosphor coating to a glass diffuser, improving the consistency and the color of the light. Placing the reflector above the phosphor layer results in more light output than other methods and less glare, according to the manufacturer. 

A unique feature of LEDs is that a single fixture with different types of diodes can create multiple temperatures and colors of light, opening new design possibilities for accent lighting. 

One last thing: Both CFLs and LEDs can be tricky to dim. The ballasts and drivers, respectively, must be compatible with the dimmers, and the light may cut out before dimming down all the way. This information is usually indicated on the product.

 This excerpt is reprinted with permission from The Energy-Smart House, published by Taunton Press, 2011. 

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Post a comment below.


1/24/2012 5:21:14 PM
LED is about a clean as you get.

Jason Hinton
1/23/2012 2:32:41 PM
I know who Al Gore is. Again, what does THIS law have to do with Al Gore? The Energy Independence and Security Act of 2007 was passed with broad bipartisan in congress and signed into law by George W. Bush. If you are going to blame someone blame the right people. ------------ Am I trying to save the earth? No, the earth did just fine before humans existed and will still be doing fine once we are gone. I guess it was my Midwestern upbringing and its Puritan influence that simply makes me believe that wasting resources is wrong. --------------- Having spent 2/3's of my life in Michigan I understand the limitations of CFL's in cold environments. I also understand the halogen incandescent bulbs do not have cold start issues. How many halogen incandescent bulbs have I purchased? None. However, at $3.50 for a two pack I really doubt they would break the bank. I may purchase one for our front porch light to replace our one remaining standard incandescent bulb. We converted all of our interior lights to CFL's back in 2000. That was when each bulb was $10, so we purchased one or two per pay period. The majority of those GE bulbs are still working more than 10 years later.

1/23/2012 5:36:44 AM
Which planet are you from? Al Gore? Apparently you don't live in cold weather and the nights are longer during the winter. You need brights lights to check the inside a unheated building and other uses for momentary lights required. I use CFL's in places that are warm and the lighting is on for more than 15 minutes. 100, 60,and 40 CFL's in the dining room, kitchen, living room etc. 300 and 200 CFL's in my farm shop. Why are you worried about inefficiency, going to save the planet? How many halogen incandescent bulb have you bought? Did it break your pocket book?

Jason Hinton
1/23/2012 12:25:41 AM
Why did you lose your freedom of choice and what does Al Gore have to do with this? You can still buy an incandescent light bulb the store. You just can't buy a very inefficient 100 watt bulb. Instead you will be required to purchase a 72 watt halogen incandescent bulb that puts out the same amount of light as an old 100 watt bulb. Check out Philip's EcoVantage line of bulbs. This is the same technology that we have been using for 50 years in car headlights packaged into the shape of a standard light bulb.

1/22/2012 12:12:25 AM
Screw the CFLs, I use CFL's in half of my house and farm where needed. I lost my freedom of choice, thanks to Al Gore and politicians.

Dennis Smith
1/21/2012 4:43:01 PM
In addition to CFl's not lasting as long as advertised I hope that we don't end up with the law of unintended consequences biting us. 4-5mg of Mercury is a lot. It is bunk that coal fired plants are a greater source of mercury if you happen to break a CFL. The homeowner has no way of really removing the mercury and since it is a neurotoxin the build up would be worse than the lead problems of yesteryear. We do not need to be putting this type of poisons in our homes. Next time you move into an existing home think of what might be in it.

1/21/2012 2:19:21 AM
The LEDs which emit white light, of the sort you'd use to light a home, do not contain any arsenic. LEDs which emit red, orange, yellow, or pale-green light do contain traces of arsenic, but it is bound up as a compound with other elements, and then encapsulated inside the clear epoxy body of the LED.

Jim Roche
1/21/2012 1:21:47 AM
So far I have never seen a CFL that last even close to the ten or eleven thousand hours promised by most manufacturers. In fact, most last about the same as an incandescent bulb. Because of the savings in electricity usage and cost, CFL's are still worth buying but certainly not for the promised savings. The other issues then come to the fore. Regulators and other interested parties have done a really bad job in selling these technologies to the public.

Bryce Rieger
1/21/2012 12:57:40 AM
CFL's are highly subsidized to hide their TRUE cost. They also do not provide the service life touted by the Industry in a real life use situation. Paul Wheaton has done some very good testing to prove this. See his article on CFL's @ and his forum @ While your there check out his articles on hugelkultur and rocket mass heaters.

1/21/2012 12:04:57 AM
Elemental Hg is NOT toxic. That's why it was used for centuries in medical thermometers. It was removed from that application only because our courts do not function with scientific rationale, but feed on emotional argument. Even compounded Hg has an LD50 somewhere from 1-15 mg/kg (There's no data from humans. Other species have highly variable differences), So, even at the higher end of toxicity, for average 70 kg men, half would survive an exposure of 70 mg. Even if CFLs contained Hg salt, you'd have to eat 14 CFLs to get that exposure. EPA's numbers were pulled out of their bureaucratic posteriors and have no basis in science. The only large scale example of human exposure to Hg nerve gas was when Chemical Ali, during the Saddam Hussein regime, bombed the Kurds. It was noted then that nobody with an exposure of less than 400mg/kg got sick....Hg isn't the reason CFLs are a scam. It's the colllusion between Jefrey Imelt, head of GE and close consultant to Obama and his GreenDreamTeam to get incandescents outlawed so GE could close its US plants and shift operations to China. Congress has since acted to rescind those regs, but, oops--too late-- the factories here are already closed. GE stockholders will just have find consolation in their bigger dividend checks.

1/20/2012 9:17:04 PM
The fact that they're made in China is one of the main reasons why I won't buy them. How can anything made in China be considered energy efficient, environmentally safe, economically responsible, or ecologically friendly? It can't. Just the shipping uses up a ridiculous amount of resources.

1/20/2012 8:47:54 PM
What about the arsenic in LED's?

Rod Naugler
1/20/2012 8:23:19 PM
I've been testing some LED bulbs from China. Presently, this one is the best deal I've found with good price and great light. Roughly equivalent to a 40W incandescent or a 7W CFL.

Stephen Tane
1/20/2012 7:40:08 PM
I'm not sold on CFL. We have had several of them fail in less than one year and one even started to smoke and burn - fortunately we were home at the time and discovered it. These are too expensive to replace in less than one year and you don't recoup the cost thru energy savings. And lets not even discuss the mercury content. Quality is not there. An infinitely better alternative are halogen lamps which are available in all sizes now at a reasonable cost. They won't smoke or catch fire. Or LED lamps are good but still costly at this time.

chantal haines
1/20/2012 6:54:55 PM
I'm not buying into this.These bulbs are highly toxic.They have to be individually wrapped and shipped to the centers that handle them,,which can be hundreds or more miles away, more fossil fuel burned..Most people WIIL NOT recycle these bulbs so our groundwater,and soils will now become highly toxic with mercury and arsenic.50 yrs from now people will be asking what the hell we were thinking as they try to figure out how to deal with the mercury.And as far as ONLY 5 mg per bulb.Let's do a little math.According to the EPA 50 mg of mercury will contaminate a 10 acre lake.The average household uses at least 24 or more do the math!THERE IS NO SAFE LEVEL OF MERCURY.........................NONE NOT EVEN A LITTLE.

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