Tuesday, November 22, 2011

LED Light Bulbs - A Bright Idea Whose Time Has Come

My lights at home have been annoying me lately. I have dimmers on most of my lights, but I get a high pitched buzzing that is very unpleasant whenever I actually use the dimmers. Last week, I had another problem. The light bulb that is part of my bathroom fan died and I needed a replacement. Without thinking about it, I bought the compact fluorescent bulb size that matched the fixture only to discover that the new lamp’s color was far too yellow, which makes my bathroom look weird.

Coincidentally, I also happened to read a book about the health effects of light. In the book, there was a discussion about the value of full spectrum lighting (lights that mimic daylight) and the book explained that most indoor lights give off too much light in the red/orange range while having too little light in the blue range. This is compared to natural outdoor light which is the healthiest and has a more balanced proportion of all colors. As I looked into how to solve my lighting problems, my research turned up a lot of useful information that I thought I would share with you.

What I found is that if you happen to be looking for ways to reduce your energy usage, help the environment, and save money all at the same time, it turns out that changing your lights from the old style incandescent light bulbs for newer technology is a great place to start. But how do you choose which type is right for your home and your health?


Traditional Light Bulbs

Incandescent light bulb technology is well over a hundred years old. It has many drawbacks when compared with more modern lighting technologies, with only one real benefit; they are very inexpensive to purchase. Incandescent bulbs cost around $0.50 to buy, and you can find them at this price just about anywhere.

Incandescent bulbs use heat to generate light, and in doing so generate far more heat than light. In order to generate light, the filament in the bulb is heated from 3,000-5,000 F, causing it to literally get white-hot and glow. A 60 Watt incandescent bulb uses 60 Watts of power to do this, but only about 2% of that energy ends up turning into useful visible light. The vast majority of the energy spent is given off as heat, in the form of infrared light.

Clearly, this inefficient and, frankly, wasteful technology is long overdue to be replaced.

The Options -- LEDs and CFLs

A typical compact fluorescent light bulb.
The CFL (Compact Fluorescent Lamp) was the first major competitor to try to replace the incandescent bulb. At the same visible level of lighting, a CFL uses a little under half the amount of power as an incandescent. CFLs are relatively inexpensive and last up to 8x longer than an incandescent bulb.

However, there are some serious drawbacks to fluorescent lighting. The life of a CFL is greatly reduced if it is switched on and off frequently and can, through this problem, be comparable in lifespan to an incandescent. This makes them poor choices for motion activated lighting. Also, they are not rated to run with the base of the bulb pointed up (as in most recessed ceiling lighting), as this increases the amount of heat in the electronic ballast (circuitry in the base that powers the light), lowering the bulb’s life. CFLs are also not rated for outdoor use. Like their larger fluorescent tube brethren, CFLs are quite fragile (made of glass) and all contain small amounts of highly toxic mercury.

New LED light bulbs are a smart replacement for old bulbs.
LED (light emitting diode) based light bulbs are gaining popularity as a replacement for standard incandescent bulbs and, more recently, CFLs (compact fluorescent lamps). LEDs utilize a reaction between electricity and certain combinations of chemicals to produce certain wavelengths of light. This conversion is extremely efficient and produces light that is crisp and even, while using a fraction of the power that incandescent or fluorescent lighting uses.

LED lighting not only reduces the amount of energy used to produce a given amount of light, but it also offers a number of other advancements over other sources of light. LEDs produce light very efficiently with very little energy wasted as heat. Newer dimmable LEDs can dim from 10-100% of total output with no color distortion or the tinny humming usually associated with dimmers. The color rendering (how accurately the color of things looks under the light) of high end LED bulbs surpasses that of CFLs and even most incandescent bulbs. Overall LEDs are a clear winner in terms of almost all the categories you might consider when replacing incandescent lights.

Energy Savings

First and foremost, the energy (and therefore monetary) savings of using LED lighting is significant. Since they use roughly 1/5 to 1/10 the amount of energy as incandescent bulbs, replacing all the lights in your house can cut down on your electricity bill considerably. LEDs even use about half the energy of CFLs.

LEDs also don’t generate large amounts of heat like incandescent bulbs. If you’ve ever changed an incandescent bulb after it’s been on for even a few minutes, you know how incredibly hot they can get (and stay, even after you turn off the light). This heat is, for all intents and purposes, wasted electricity. In fact, the vast majority of the energy used by incandescent lights is given off as heat. An incandescent light bulb is what makes an “Easy Bake Oven” hot enough to actually bake things.

In the summer time, you spend even more energy using air conditioning or fans trying to offset these incandescent mini-heaters in your house (air conditioning systems are sized to take lights into account by design). But, LED lights only get slightly warm to the touch when they’re on (often <100 F), so you can save even more energy spent on cooling your home during hot days.

Bulb Life

LEDs last longer and save
you more money than
compact fluorescents.
An LED based light will last much longer than CFLs or incandescent lights. Whereas “normal” incandescent lights typically last about 1,000 hours of use and CFLs can last up to 8,000 hours of use, quality LED lights last over 50,000 hours of use. Incandescent and (especially) CFL lights also last fewer hours the more you switch them on and off, but LEDs do not suffer this limitation. For reference, one year is 8,760 hours and at typical usage of 8 hours per day, LED lights can last 10-15 years before needing to be replaced.

It’s important to remember that true cost of a 100W incandescent light bulb isn’t just the $0.50 price of the bulb. The true cost also includes the electricity used over the 1000 hour life of the bulb, which averages to about $12 for people in the US. So, each 100W incandescent bulb, in reality, costs you $12.50, not just $0.50 at the store.

A typical CFL bulb lasts about as long as eight incandescent bulbs (8,000 hours). If you buy eight incandescent bulbs instead of just one CFL, the real cost of the lighting from those eight incandescents adds up to $100! So you end up saving about $70 (of that $100) for every 26W CFL that you buy and use in place of incandescent lighting. Purely based on financial concerns, putting one or two CFLs into your home will save you a considerable amount of money.

But now that LED lamps that provide as much light as a 100W incandescent bulb are becoming available soon, the choice of alternatives may be somewhat more difficult to make. These 100W replacement LED bulbs use only 20-25 Watts and last 25-50x longer than a 100W incandescent. The kicker is that they will probably cost around $50 or more.

So, the payback time for an LED like this, based on energy savings, will be in the area of about five years versus the three to six month range for a CFL. Over the life of the bulb, however, the LED still offers the best value for your money.

Dimming

If you have dimmers in your home, you’re probably quite familiar with two of the major drawbacks. When you dim an incandescent light, you can pretty easily see the color quality change to an orange hue, washing out the colors of objects in the room. There is also the issue of the metallic humming sound that comes from the bulbs, sometimes even when the dimmers are turned all the way up.

Newer CFLs are able to be dimmed, but they require special dimming switches to make them work. Standard dimmers for incandescent lights will not only reduce the lifespan of a CFL, but may also void the warranty. Due to the additional circuitry needed to make them so, dimmable CFLs cost more than normal CFLs. A further limitation is that multiple dimmable CFLs on the same dimmer switch might not appear to be at the same brightness level. On the positive side, CFLs generally do not distort the color of light when dimmed, like incandescents do.

LEDs come out on top again, providing the best quality of light when you dim them. Like CFLs, the LED bulb you wish to use needs to be specifically labeled as “dimmable”. But, dimmable LED bulbs do not require special light switches to operate. They work with any standard dimmer switch, and thus serve as a better drop-in replacement for incandescent bulbs already on a dimmer. LEDs also don’t change color when dimmed, they simply lower the output of light, meaning that they won’t wash out colors as they dim. Dimming an LED, unlike with incandescent or CFLs, actually increases its life making them a clear winner here.

Color Temperature

When you buy light bulbs of any kind, you have a choice between “warm white” and “cool white”. The difference in color between these two options is what is known as color “temperature”. This isn’t a measure of temperature in the common sense of the word, but rather a scale by which shades of light are measured. Color temperatures are measured in kelvins (K) and are labelled on the packaging of any light you might buy.

A basic idea of color temperatures in lights.
Color temperatures over 5,000K are called “cool” colors (blueish white), while lower color temperatures (2,700–3,000 K) are called “warm” colors (yellowish white through red). As a point of reference, the sky on an overcast day is around 6,500K, moonlight is around 4,500K, a candle’s flame and sunrise/sunset is around 1850K, and “normal” afternoon daylight is around 5,000K.

Incandescent bulbs, when dimmed, change their color temperature greatly while LEDs and CFLs do not. Since most people are used to the color temperature getting warmer (orange-red) when the light is dimmed, you might find it very different to have cool white colors at low intensity. If you intend to use dimmable LEDs, you should experiment and see if warm or cool white bulbs are right for you.

The Health Risks of CFLs - Toxic Chemicals and UV light

CFLs contain highly toxic mercury.
Fluorescent lighting, though it saves energy, has some dangerous byproducts. In a fluorescent lamp, the mercury is charged with high voltage electricity until it becomes a gas. Once this happens, the mercury gas starts to give off UV light. The inside of the tube is coated with a chemical known as a “phosphor” that, when hit with UV light, jiggles around and converts the UV light into the more useful visible light that lights our offices, supermarkets, and stores. (“Black Lights” are usually just fluorescent lamps without the phosphor, therefore giving off all UV light.) Unfortunately, the phosphor can degrade over time and ends up letting some of the UV light through.

If you look at an old fluorescent fixture, you may see the plastic cover looking a little yellow; that discoloration is a telltale sign of UV damage. Fluorescent bulbs can damage paintings and textiles which have light-sensitive dyes and pigments. Strong colors will also tend to fade on exposure to UV light. Working underneath fluorescent lights for any length of time can expose you to dangerous UV radiation. For a look at the health dangers of UV radiation, you may wish to consult our article on sunscreen.

The Health Benefits

There are some reported health benefits to using higher color temperatures for lighting. For indoor lighting, the color temperature of the light can have effects on your brain. For example, warmer lights (similar to light in the late afternoon or evening) are often used in public areas to promote relaxation. Cooler light (more similar to daylight) is used to enhance concentration in offices. The health benefits of cool white lighting are related to the increased generation of light in the blue end of the light spectrum. Research has shown that exposure to these higher color temperatures of light influences hormone secretion, heart rate, alertness, sleep cycles, body temperature, and even gene expression.

It’s important to use the right type of bulb for the right setting. Using cool white bulbs in your bedroom would probably make it harder to fall asleep, since your brain registers it as midday daylight. But, in an office or other work space, a cool white bulb would probably be a good fit, since it promotes concentration and helps prevent sleepiness. In addition, cool white lights (closer to daylight) generally reproduce colors more accurately than do warm white ones. Warm white bulbs would probably fit better in a bedroom, as the warmer colors generally help you to relax.

Quality of Light

LEDs are available for just
about any lighting use.
The quality of light that a bulb gives off is measured by a Color Rendering Index (CRI) test. While the details of the test are pretty boring, it essentially tests how well objects appear under a given light source, measured from 0 (worst) to 100 (best). If you’ve ever looked at some clothes in a shop (under fluorescent lighting) and taken them home, you probably know how different colors can look. The higher a given light bulb scores on the CRI scale, the more accurately it reproduces colors. Some other factors like dimming can lower the CRI, especially with incandescent lights.

Newer LED lights offer CRI scores of 92 or higher in both cool and warm white versions. Fluorescent lights tend to wash out colors, and all but the newest (tri-phosphor) bulbs suffer this limitation. LEDs also don’t suffer from the washing out of colors like incandescent bulbs, especially when dimming.

LEDs - The Rugged Light Bulb That’s Recyclable

The bulbs (outer part) of LED lights are made with a high strength plastic that won’t shatter if you accidentally drop them. Since they don’t have a tiny, fragile metal filament or glass surrounding them like incandescent bulbs or toxic mercury inside them like in CFLs, there is no real danger of dropping them anyway. Many manufacturers also make the circuitry in LEDs lead-free and they are virtually 100% recyclable.

These sound fantastic, so why doesn’t everyone just buy LED lights?

The main issue with LED lighting is that it costs more upfront than do CFLs or incandescent lighting. While a typical LED light will more than pay for itself (in energy and money savings) over the course of a few years, many people are put off by the idea of spending $15-50 on a single light bulb. In the long run, however, they are better for the environment and save you more money than the other options available.

LED bulbs also somewhat hard to find. They aren’t just carried by any hardware store the way the other options are. You can order them on the Internet, but without being able to see them, it’s hard to decide which you want. In addition, the quality of bulbs between manufacturers is pretty wide.

After researching companies that make and sell these bulbs, I found EarthLED. They offer a 3 year warranty on their bulbs. They also don’t use lead or other toxic chemicals in their bulbs. Best of all, their bulbs are among the highest rated in the LED industry. EarthLED is at the forefront of innovation in LED lighting and were among the first companies making dimmable and outdoor rated LEDs. I ordered some bulbs from them, and I look forward to replacing the rest of the lights in my home in the near future.

Despite these minor drawbacks, LEDs are an extremely good choice for lighting. LED replacements exist for almost every other style of bulb from flashlights to fluorescent tubes to chandeliers. You can save energy, money, and have a better quality light.

If you have any experience with LEDs in your home or at work, please let us know what you think in our comments section below.


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Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

3 comments:

  1. Bicycle Led Lights ensures your security while you are riding bicycle in dark place. It will help a lot in finding right destination.

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  3. All is explained in best way about the LED as they are truly Best Energy Saving Lights

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