Compact Fluorescent Light Bulbs
Compact fluorescent lights, or CFLs, are constantly in the news due to their energy efficient qualities. Not only do these light bulbs utilize less energy, but they produce less heat helping to save energy in cooling costs and prolonging the life of the bulb. How CFLs Work Compact fluorescent bulbs use about one fifth of the energy of an incandescent bulb to produce the same amount of light. A good comparison ratio takes an 11 watt CFL to replace a traditional 60-watt bulb. The lower wattage equals less energy use and less heat output. Look for packages that provide conversions for consumers to get the best fitting bulb for your needs. Considerations The start-up time of a compact fluorescent bulb can be slower than an incandescent bulb, even though the colour and brightness are similar. Compact fluorescent bulbs contain trace amounts of mercury, so when they burn out they need to be disposed of properly to prevent environmental damage. If you want to change the world, start by changing a few light bulbs. It is one of the best things you can do for the environment - and your budget! On top of that, replacing one regular light bulb with an approved compact fluorescent light bulb can save consumers £15 in energy costs over the life of the bulb. Compact fluorescent light bulbs use at least 80% less energy than standard incandescent bulbs to provide the same amount of light, and they last up to 10 times longer. Compact fluorescent light bulbs also generate 70 percent less heat, so they are safer to operate and can also reduce energy costs associated with cooling homes and offices.
Compact fluorescent bulbs produce light that's more diffuse than incandescent bulbs, so they are very good for area lighting.
CFLs can cause interference with devices such as radios and computers. In this event, move the lamp or the electronic devices away from each other.
Save Energy, Money and the Environment with Compact Fluorescent Light Bulbs
Reasons to Switch to Compact Fluorescent Light Bulbs
The only real drawback to using compact fluorescent bulbs is that each one contains about 5 mg of mercury, a toxic heavy metal that can cause serious health problems if inhaled or ingested over a period of time or in large enough doses. As a result, many environmentalists and other experts recommend recycling compact fluorescent light bulbs so that they don't end up in landfills.
How Much Can You Save by Using Compact Fluorescent Light Bulbs?
For most people, switching from incandescent to compact fluorescent bulbs offers a lot of opportunity for energy and cost savings.
Lighting accounts for 20 percent of the electric bill in the average UK home, and the average home has approximately 30 light fixtures.
To save the most energy and money by using compact fluorescent light bulbs,we recommend replacing standard bulbs in areas where lights are used frequently and left on for a long time, such as family rooms, living rooms, kitchens, dining rooms, and porches.
Choosing the Right Compact Fluorescent Light Bulbs
To make sure you get the same amount of light when replacing standard bulbs with compact fluorescent light bulbs, check the lumen rating on the light you are replacing and purchase a compact fluorescent light bulb with the same lumen rating. (A lumen rating is the measure of light the bulb puts out.)
Wattage varies greatly between standard light bulbs and compact fluorescent light bulbs. Compact fluorescent light bulbs typically use about one fifth of the wattage used by standard bulbs to produce the same amount of light. So to replace a traditional 60 watt bulb, look for a compact fluorescent light bulb that is about 11 watts.
Compact fluorescent light bulbs are available in many different sizes and shapes to fit in almost any fixture—from three-way lamps to dimmer switches—for both indoor and outdoor use. Compact fluorescent light bulbs also come in a variety of colour temperatures, which helps determine the colour and brightness of the light each bulb provides. (Learn more about the brightness, colour and light quality of compact fluorescent light bulbs.)
Brightness and Colour of Light
How good or poor a given light appears can be described in three basic ways: how much light is present, the quality of the light (is it bright or dull or does it produce glare?) and what its colour characteristics are.
Watts and Lumens: How much light?
Light output, measured in lumens, refers to how much light leaves a light source. Because we are so used to incandescent bulbs, we usually describe the amount of light with watts. The number of watts is actually the amount of power the bulb uses. For an incandescent bulb this can be a misleading number because 90 percent of the watts is wasted as heat instead of making light.
To compare brightness between incandescent bulbs and the more efficient compact fluorescents, the quantity of light is expressed in lumens as well as wattage. As with watts, a higher number of lumens means a stronger light. The chart shows lumen levels to look for when replacing a given bulb.
|
Incandescent
|
CFL
|
Lumens
|
| 40W | 9-11W | > 490 |
| 60W | 11-14W | > 490 |
| 75W | 15-19W | > 900 |
| 100W | 20-25W | > 1,200 |
| 150W | 26-29W | > 1,750 |
| 200W | 38-42W | > 2,600 |
If you don't want to print this page out, remember this rule of thumb: CFLs use about a fifth of the wattage to produce the same light. So to replace a traditional 60-watt bulb, look for a CFL that's about 11 watts.
Lumen output deteriorates over time from a number of factors, including the ballast's electronics, variations in supply voltage, dust and dirt.
Colour
How does a light render an object's colours, and what colour is the light itself? These characteristics are expressed through the Correlated Colour temperature (CCT) and Colour Rendering Index (CRI).
Correlated colour temperature (CCT)
Light has colour, whether it emanates from the moon, the sun or your favorite reading light. It might tend toward orange (think of parking lot lights illuminating the night), yellow (most reading lights) or white (daylight).
Imagine heating a piece of metal gradually. As it heats up, it changes colour. At first, it appears orange, then yellow and then blue or blue-white. The Correlated Colour Temperature indicates how warm or cool light is. For a light colour close to incandescent bulbs, look for a CCT range between 2650 and 3000 degrees Kelvin. This range is referred to as warm white. Common CF bulb colours are 2700K, 3000K, 3500K and 4100K. (The Kelvin scale and its units refer to absolute temperature; 0 degrees Kelvin refers to the point at which no heat energy remains in a substance.)
CCT measurements:
• 2650-3200K – warm white (yellowish-white)
• 4000K – white
• 4000K– cool
• 6500K - Daylight
Colour Rendering Index (CRI)
This is a numeric representation of a light bulb's ability to show colours "realistically," compared to a standard incandescent. The CRI scale ranges from 0 to 100—the higher the number, the closer to what you're used to. For good colour quality, look for compact fluorescents with CRIs of 80 or above.
Light Technology Basics
About 85 percent of our perceptions come from our eyes, so lighting is important to what we do whether we're aware of it or not. Light can be produced naturally (like sunlight) or artificially.
To produce artificial light, electrical energy is transformed into light. This generally occurs in one of two ways:
• Incandescence, in which current passes through a filament, which heats and then glows, or
• Gas discharge, in which current passes through a gas. The atoms glow, giving off ultraviolet light, which reacts with phosphor to produce visible light.
Energy-saving compact fluorescent light bulbs produce light using gas discharge.
