Time to switch CFL to LED (Energy Efficient Lighting)

Electric lighting burns up to 25% of the average home energy budget.

The electricity used over the lifetime of a single incandescent bulb costs 5 to 10 times the original purchase price of the bulb itself.

Compact Fluorescent Lights (CFL) and Light Emitting Diode (LED) bulbs have revolutionized energy-efficient lighting.

CFLs are simply miniature versions of full-sized fluorescents. They screw into standard lamp sockets, and give off light that looks just like the common incandescent bulbs - not like the fluorescent lighting we associate with factories and schools.

LEDs are small, solid light bulbs which are extremely energy-efficient. New LED bulbs are grouped in clusters with diffuser lenses which have broadened the applications for LED use in the home.

It is important to buy high quality bulbs, or the quality of light will be poor, and they will burn out prematurely.

LED Lighting

LEDs (Light Emitting Diodes) are solid light bulbs which are extremely energy-efficient. Until recently, LEDs were limited to single-bulb use in applications such as instrument panels, electronics, pen lights and, more recently, strings of indoor and outdoor Christmas lights.

Manufacturers have expanded the application of LEDs by "clustering" the small bulbs. The first clustered bulbs were used for battery powered items such as flashlights and headlamps. Today, LED bulbs are made using as many as 180 bulbs per cluster, and encased in diffuser lenses which spread the light in wider beams. Now available with standard bases which fit common household light fixtures, LEDs are the next generation in home lighting.

The high cost of producing LEDs has been a roadblock to widespread use. However, researchers at Purdue University have recently developed a process for using inexpensive silicon wafers to replace the expensive sapphire-based technology. This promises to bring LEDs into competitive pricing with CFLs and incandescents. LEDs may soon become the standard for most lighting needs. .

Benefits of LED lightbulbs

Long-lasting - LED bulbs last up to 10 times as long as compact fluorescents, and far longer than typical incandescents.

Durable - since LEDs do not have a filament, they are not damaged under circumstances when a regular incandescent bulb would be broken. Because they are solid, LED bulbs hold up well to jarring and bumping.

Cool - these bulbs do not cause heat build-up; LEDs produce 3.4 btu's/hour, compared to 85 for incandescent bulbs. This also cuts down on air conditioning costs in the home.

Mercury-free - No Mercury is used in the manufacturing of LEDs.

More efficient - LED light bulbs use only 2-10 watts of electricity (1/3rd to 1/30th of Incandescent or CFL) Small LED flashlight bulbs will extend battery life 10 to 15 times longer than with incandescent bulbs. Also, because these bulbs last for years, energy is saved in maintenance and replacement costs. For example, many cities in the US are replacing their incandescent traffic lights with LED arrays because the electricity costs can be reduced by 80% or more.

Cost-effective - although LEDs are expensive, the cost is recouped over time and in battery savings. For the AC bulbs and large cluster arrays, the best value comes from commercial use where maintenance and replacement costs are expensive.

Light for remote areas - because of the low power requirement for LEDs, using solar panels becomes more practical and less expensive than running an electric line or using a generator for lighting.

Limitations of CFL lightbulbs

Although CFLs are an excellent source of energy-efficient lighting, they are not always the best choice for all lighting applications. Here are a few limitations to consider:

On/Off cycling: CFLs are sensitive to frequent on/off cycling. Their rated lifetimes of 10,000 hours are reduced in applications where the light is switched on and off very often. Closets and other places where lights are needed for brief illumination should use incandescent or LED bulbs.

Dimmers: Dimmable CFLs are available for lights using a dimmer switch, but check the package; not all CFLs can be used on dimmer switches. Using a regular CFL with a dimmer can shorten the bulb life span.

Timers: Most CFLs can be used with a timer, however some timers have parts which are incompatible with CFLs; to check your timer, consult the timer package or manufacturer. Using an incompatible timer can shorten the life of a CFL bulb.

Outdoors: CFLs can be used outdoors, but should be covered or shaded from the elements. Low temperatures may reduce light levels - check the package label to see if the bulb is suited for outdoor use.

Retail lighting: CFLs are not spot lights. Retail store display lighting usually requires narrow focus beams for stronger spot lighting. CFLs are better for area lighting.

Mercury content: CFLs contain small amounts of mercury which is a toxic metal. This metal may be released if the bulb is broken, or during disposal. For more information about mercury and CFLs, see below.

The principle reason for reduced lifespan of CFLs is heat. CFLs exhibit shorter lifespans in light fixtures and sockets where there is low air-flow and heat build-up such as recessed lighting. For these types of sockets it is recommended to ues specially designed CFLs for recessed lighting or LEDs. Another main reason for reduced lifespan of CFLs is too-frequent on/off cycling. These bulbs should be used where they will be left on for steady periods without being flicked on and off.

Mercury and CFLs

Mercury is a toxic metal associated with contamination of water, fish, and food supplies, and can lead to adverse health affects. A CFL bulb generally contains an average of 5 mg of mercury (about one-fifth of that found in the average watch battery, and less than 1/100th of the mercury found in an amalgam dental filling). A power plant will emit 10mg of mercury to produce the electricity to run an incandescent bulb compared to only 2.4mg of mercury to run a CFL for the same time. The net benefit of using the more energy efficient lamp is positive, and this is especially true if the mercury in the fluorescent lamp is kept out of the waste stream when the lamp expires.

Cost Comparison between LEDs, CFLs and Incandescent light bulbs

	LED	CFL	Incandescent
Light bulb projected lifespan	50,000 hours	10,000 hours	1,200 hours
Watts per bulb (equiv. 60 watts)	6	14	60
Cost per bulb	$35.95	$3.95	$1.25
KWh of electricity used over 50,000 hours	300	700	3000
Cost of electricity (@ 0.20per KWh)	$60	$140	$600
Bulbs needed for 50k hours of use	1	5	42
Equivalent 50k hours bulb expense	$35.95	$19.75	$52.50
Total cost for 50k hours	$95.95	$159.75	$652.50

Refrence
http://www.buildingstuff.biz/led_lights_11.html
http://www.ledcentral.com.au/led-products