Compact Fluorescent Light (CFL) Bulbs versus Incandescent bulbs

A compact fluorescent lamp (CFL), also known as a compact fluorescent light or energy saving light (or less commonly as a compact fluorescent tube), is a type of fluorescent lamp. Many CFLs are designed to replace an incandescent lamp and can fit into most existing light fixtures formerly used for incandescents.  The typical household still uses incandescent light bulbs, spending more amount on electricity bills. Use of compact fluorescent light (CFL) can reduce this expense markedly.  Moreover, replacing energy-hogging incandescents with energy-saving fluorescents (CFLs) is a simple, effective way to slow the rate of global climate change while saving money. It's good for the environment, it's economical, it's efficient, and it's easy

How is light produced in CFLs?

CFL bulbs emit light that is a mixture of three phosphors exposed to ultraviolet light produced by mercury atoms. This process is unlike incandescent bulbs, which use filaments. Though CFLs cost more at the onset, they are tested to provide 8,000 hours of light as against the 500-2,000 hours from incandescent bulbs.  Here is the math—an 18-watt CFL saves you from purchasing ten ordinary 75-watt incandescent bulbs.  Mercury is used in many household items: thermostats, thermometers, fluorescent lights, batteries and switches for appliances, lights and automobiles. Exposure to large quantities of mercury in our air, water and fish we eat is a documented risk to human health. An extremely small amount of mercury-an average of four milligrams-is sealed within the glass tubing of a CFL. This is said to be about the size of the period at the end of this sentence. It is an essential, irreplaceable element in CFLs, and it's what allows the bulb to be such an efficient light source. The mercury in a CFL is no threat to the environment unless the glass is broken. For a basis of comparison, there are about one to three grams of mercury in your average home thermometer. It would take between 250 to 1000 CFLs to equal that same amount. Ironically, a regular incandescent light bulb actually releases much more mercury into the environment than a CFL.

Why are CFLs more cost-efficient than incandescent bulbs?

Incandescent bulbs manage to convert only 10% of electricity to visible light, with the remaining 90% converting to heat. Hence, using more efficient lighting can substantially curtail electricity consumption. Replacing the commonly used incandescent bulbs with CFLs is expected to cut electricity use for lighting by half, further reducing the annual carbon dioxide emissions by about 125 billion pounds.

Different types of CFLs

• CFLs can be used in various types of light fixtures like table lamps, ceiling lights, spotlights, etc. and they come in a variety of styles too.
• Twin Tube Lamps have two tubes in the lamp, aligned in a parallel manner. Also called Biax or Dulux, they fit into lamps, recessed ceiling lights, and wall lights.
• Quad Tube Lamps are the same as twin tubes of similar wattage at half the length. These bulbs fit better in smaller fixtures like lamps. They are also called double Biax, PL Clusters or PLC lamps.
• Triple Biax Lamps generate more light in a shorter body. Providing a high amount of light output in a small-sized bulb shape, they easily fit into fixtures meant for incandescent bulbs.
• Spiral Lamps are a spirally-shaped continuous tube lamp. In shape and light output qualities, it equals a standard incandescent bulb. Therefore, it is the most popular model of CFLs.
• F lamps are similar to quad tubes except that their two tubes are aligned from top to bottom instead of side to side. Therefore, the shape resembles an F. They are frequently used as task lights and in low-profile recessed fixtures.
• Circular (Circline) lamps are usually designed for reading lamps. They come in two types: one giving the 'cool white' light, like the common bulbs, and the other having the warm light.
• As substitutes to the prevalently used bulbs, CFLs are available in various sizes and shapes, and produce warm light similar to that produced by an incandescent bulb. Earlier, CFLs were larger than ordinary light bulbs. Now they are getting smaller and fit in most light fixtures. Newer models are fitted with electronic circuitry, making them lighter and more compact.
• CFLs use only up to one-fourth to one-third of the electric requirement of incandescent bulbs while having ten times the life of the latter. Their regular use can have tremendous environmental benefits. Since electricity is usually produced from coal, and each CFL cuts down carbon dioxide emissions by about 1,300 pounds over its lifetime, using CFLs amounts to a lot of energy savings in the environment.

Tips to get the most out of your CFLs

• Avoid turning off the bulbs too frequently as that shortens their lifespan and wastes energy.
• Check the packaging to learn about the intended functionality of the bulb and use it accordingly. If you use a CFL that does not work well in conditions of high heat or humidity like bathrooms, then you will not get the maximum output from your CFL.
• Using dimmers is a very effective way to reduce power consumption for all bulbs.
• Look for appropriate certification products for guaranteed quality and performance.

Source(s):  

1. http://www.concernergy.com/residential_lighting_compact-fluorescent-light-bulbs_8#more  
2. http://www.michigan.gov/deq/0,1607,7-135-3585_30068_30172-90210--,00.html