Compact Fluorescent Lamp (CFL) bulb
A compact fluorescent lamp (bulb) is a miniature/miniaturized fluorescent lamp (usually tubular in form). Something to remember is that all fluorescent lamps whether its compact or not will require a ballast for the lamp to be able to function.
An ENERGY STAR qualified compact fluorescent light bulb (CFL) will save about $30 over its lifetime and pay for itself in about 6 months. It uses 75 percent less energy and lasts about 10 times longer than an incandescent bulb.
DID YOU KNOW?
If every American home replaced just one light with an ENERGY STAR light, we would save enough energy to light more than 3 million homes for a year, about $700 million in annual energy costs, and prevent 9 billion pounds of greenhouse gas emissions per year, equivalent to the emissions of about 800,000 cars.
What are the types of Compact Fluorescent Lamps (CFL) Available?
There are two types of compact fluorescent lamps:
Screw Based: directly replaces incandescent lamps in incandescent lamp sockets
Plug in Base: designed to fit into sockets in luminaries designed specifically for compact fluorescent lamps
What are the typical sizes of Fluorescent Lamps?
Longest length of a fluorescent tube lamp is 8' long while the shortest can be 4". The most typically used lamp size is 4'.
Typical diameters are:
- 5/8" (T-5) - having a high output light source and becoming more popular for a typical lighting system
- 1" (T-8) - general all purpose use
- 1/2" (T-12) - an older style lamp that can be less energy efficient
What are the benefits of a Compact Fluorescent Lamp (CFL) and a Fluorescent Tube Lamp?
There are many benefits upon purchasing or using a compact fluorescent lamp. Here are some of the benefits when making your decision:
- energy efficiency
- good to excellent in color
- availability for dimmer switches and options (15 watt, 18 watt and 25 watt spirals usually come in dimmable form)
- most modern fixtures now are compatible with CFL
- has a longer life compared to that of an incandescent lamp (typical life range is from 6,000-10,000 hours or more)
- its less yellow in color thus creating a cooler temperature output
- there are tri-color lamps available for fluorescent lamps (tubes are available in 4ft and 8ft)
- gives off diffused shadowless light
- tube lamps are available in warm white and deluxe warm white to help improve color rendition, this helps make your lighting source more comfortable
- if your space originally had these types of lamps, make sure they are re-lamped with the same source otherwise, there might be a difference in your lighting source
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What are the disadvantages of Fluorescent Lamps?
While there are benefits to this particular lamp there are also things one should know about when making a decision on a light source to purchase. Though fluorescent lamps are readily used in the commercial arena they are making their way for use in our homes. Yet some disadvantages that one must keep in mind are:
- they are sensitive to temperature (as many lamps are)
- this lamp does not give off a sufficient light source when the space is too cold or too hot, it works at its best in a room temperature space
- if the lamp does not start it is because its too cold and the lamp has reached below the minimum requirement for the ballast's starting temperature rating
- keep in mind that the information for the minimum temperature rating for a ballast is always available to you
- this particular lamp can be dimmed, but only with a use of an electronic dimming ballast: dimming range is typically 10-100% of light or better while some of the best ballasts might have a dimming range of 0.5-100%
- if a fluorescent lamp is dimmed it tends to be more purple in color output, in other words, when the lamp reaches lower output levels the lamp will change its color source
- though this lamp produces shadowless light sources it also might affect how we visually see detail
- the basic "daylight tube" is the most economical, but tends to project a blue-greenish light source that might affect your objects visually when looked at
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Why is noise coming from my Fluorescent Lamp?
While there are benefits to this particular lamp there are also things one should know about when making a decision on a light source to purchase. Though fluorescent lamps are readily used in the commercial arena they are making their way for use in our homes. Yet some disadvantages that one must keep in mind are:
- over time the ballast will create a humming sound
- as the ballast weakens uncomfortable flickering will occur
- the lamp will begin giving off heat over time
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Can ENERGY STAR qualified CFLs be used with dimmer switches?
Yes, certain ENERGY STAR qualified CFLs are made to work on dimmers. Be sure to check the fine print on the back of the packaging for the proper applications to see if there are any restrictions on the product’s use. Dimming an ENERGY STAR qualified CFL that is not designed to work with a dimmer switch can shorten its life significantly.
In addition to this, there are CFL manufacturers who are trying to bridge the gap to dimming. There are brands like Neptune who have recently developed a line of CFLs capable of dimming. Before committing yourself to buying more than necessary, purchase one to test. Gauge for yourself whether it meets your dimming standards.
CFL ballasts are designed for a specific input voltage and are not designed to handle changes in input voltage, and imposing them can cause the circuitry to malfunction or not be able to effectively light the lamp or keep the current through the lamp well regulated. This can significantly shorten the lifespan of the product.
Newer dimmers are actually semiconductor devices that turn the switch on and off very rapidly - 120 times per second in normal designs. Because CFLs have a finite start-up time, and because frequent switching shortens bulb lifetime, these switches prevent the CFL from working optimally, and cause it to burn out quickly.
Manufacturers compensate for these problems by designing the power electronics within the ballast to deal with these issues. This requires more complicated and more expensive parts. Alternatively, you can design a special dimming switch for CFLs that put those power electronics before the switch rather than after it. This is more expensive, however, and requires a bigger retrofit.
Even with this "fix" there are expectations for dimmable products that need to be addressed. First, dimmers can dim an incandescent from 100%-0% of the total light output smoothly and continuously. Even for those who have the appropriate power electronics, CFLs are not able to dim to 0%. Most dimmable CFLs can only dim to somewhere between 10 and 20% of initial light output. Second, as incandescent bulbs dim, the color of the bulbs gets "warmer," that is, the correlated color temperature drops. As CFLs dim, their color temperature remains constant. Because of this phenomenon (known as "amber shift"), many consumers who do use dimmable CFLs do not get the ambiance they are hoping for.
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Can I use a CFL that is not specifically designed to work in a dimmable light fixture, in a dimmable fixture as long as I don't use the dimmable feature?
In principle, if you NEVER dim the light, a CFL should work appropriately. However, because of the risk of users dimming the switch even accidentally, this is not something we recommend. Additionally, using a CFL on a dimming switch will likely void the product warranty even if the switch is never dimmed. If you wish to use a CFL on a dimmer, we recommend that you look for bulbs that indicate they are compatible with dimmers on their packaging.
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sources:
Energy Star: www.energystar.gov
http://nemesis.lonestar.org/reference/electricity/fluorescent/safety.html