CFLs: An overview
Compact fluorescent bulbs—usually
referred to by the initials “CFL”—
have come a long way. Early versions
were expensive (as much as
$15 apiece) and plagued with problems
(they appeared dim, flickered, didn’t
come on instantly and burned out sooner
But that was then. New technology has solved most
of the old problems. Today, using CFLs is one of the easiest
and most effective ways to save money on energy.
It’s as easy as screwing in a bulb and flipping a switch.
Many CFLs can be purchased for about $3 or less, and some
utility companies offer discounts or rebates to customers
who buy them.
That said, buying and using CFLs can still be confusing.
The answers to these common questions will help
you put these great energy-saving bulbs to best use.
How to choose CFL bulbs
Answer: Look at the lumen rating, not the
bulb wattage, to compare real light
output. Then buy a CFL with 20 percent
more lumens than the incandescent
bulb you want to replace has. For
example, to replace a 60-watt
incandescent bulb that has 870
lumens, buy a CFL with at least
1,050 lumens. If you follow
wattage guidelines on the package,
you may not be satisfied
with the light output. Be
wary of CFLs that don’t list
the lumens on the packaging.
Their claims that the light output
matches a certain incandescent
wattage are sometimes misleading
Another reason you need
more lumens is that a CFL
will dim over time. It will
lose 20 to 25 percent lumen
power after 4,000 hours (40
percent of a CFL’s 10,000-hour-rated life). Incandescent
bulbs also lose
lumens, but the life of
these bulbs is extremely
short compared with that
Best (and worst) places to use them
Question: Are there some places where using a
CFL makes more sense than others?
Answer: Since many CFLs last up to 10 times as long as
incandescents, consider placing them in difficult-to-
reach fixtures. It may mean climbing the ladder once
every five years instead of every year. It also makes sense
to use CFLs in light fixtures that are continuously “On”
more than three hours per day.
CFLs save energy in any location, but there are some
circumstances that can reduce their life span:
- Frequent on-off switching, as in a hallway.
- Excessive vibration near doors or stairways.
- High-humidity areas such as a damp basement.
- A CFL that’s not rated for use in an enclosed light fixture might burn out prematurely if enclosed.
Payback: How long? How come?
Answer: Although CFLs have come down dramatically
in price, their electronic ballast and
other features do make them more expensive to
manufacture than incandescent bulbs. The payback
period will vary with the cost of electricity
in your area. However, based on a cost of 10¢ per
kWh, a 15-watt CFL will cost about $12 to operate
over its 8,000-hour projected life span.
Burning a 60-watt incandescent bulb with equivalent
light output for the same length of time will
cost about $48; a cost difference of $36 (and
you’ll need to buy four to eight bulbs since they
have a much shorter life span). Based on those
numbers, a CFL will pay for itself in about 500
hours (in about four months if the bulb is used
four hours per day).
There is a small power
surge and a small spike
in electrical usage when
most lights are turned on,
but as a rule of thumb,
you'll save money by
turning off lights that will
remain off for more than
CFLs vs. incandescent bulbs
Answer: Standard incandescent bulbs work by using electricity
to heat up a thin filament inside the bulb. As the filament
heats up, it glows, producing light. The drawback to standard
bulbs is that most of the energy consumed—over 80 percent—goes into creating heat, not light.
CFLs work on a totally different principle. They consist of
two basic parts: a gas-filled tube (what many of us would call
the “bulb”) and a ballast that contains the electronics. In simple
terms, electricity from the ballast excites phosphors on the
inside surface of the bulb; these phosphors in turn glow, producing
light. Since CFLs don’t waste as much energy creating
heat, they’re much more energy efficient. You see the savings
when you compare the wattages; a 15-watt CFL provides about
as much light as a 60-watt incandescent bulb.
What a Watt Costs
The cost of electricity in the United
States ranges from less than 10¢ per
kilowatt hour to nearly 40¢ per kilowatt
hour. The more expensive your
electricity, the faster you'll recoup the
extra money you pay for CFLs.
The "quality of light" factor
Answer: Because CFLs last so long, some of the first-generation bulbs are still burning and giving people the wrong impression of the newer CFLs.
The newer bulbs flicker less, make less noise, start up faster and emit light very similar to that of standard (“Type A”) incandescent bulbs. The spiral shape, which is often used in CFLs, casts light more
like a standard incandescent bulb. The color of the light has improved dramatically. If you couldn’t see the bulb, you wouldn't know whether the light was incandescent or fluorescent. “Daylight” bulbs, which broadcast a whiter light, are available for those desiring a cooler, less yellowish light.
Dim the lights
Answer: Yes—but only if you buy the right
ones. Look for CFLs that are labeled
“dimmable” on the package; they have special
ballasts that allow them to be operated
using a standard incandescent dimmer
switch. Expect to pay more for a dimmable CFL than for a regular CFL.
Outside in the cold
Answer: Yes, they’re great energy savers outdoors, but beware. Older
fluorescent lights—both compact and tubular—are powered using
magnetic ballasts. The lower the temperature, the more difficult it is for
these bulbs to “get up to speed” and operate evenly. However, most CFLs
made today have electronic ballasts that are much less sensitive to the cold.
If you’re planning to use a CFL in an area exposed to the elements, purchase
one designated for “exterior” or “outside” use. These usually have an
extra translucent shell surrounding the fluorescent bulb for additional
protection. Specialty bulbs like the “bug light” shown and exterior floodlights
are also available.
New CFLs on the block
Answer: The pin-type fluorescent bulb familiar to
most of us is the classic circular kitchen
bulb. These aren’t considered true
CFLs since the ballast is in the fixture, not built
into the bulb itself.
But there is a new generation of pin-type
bulbs, like the bulb shown at the top of the photo.
These are true CFLs, but they have a base
designed to fit only into fixtures made specifically
for these pin-type bulbs. Another unique feature
of these bulbs is that the ballasts and tubes
are separate. One of the reasons behind this modular
design is that a typical ballast can last 30,000
hours, while a typical CFL bulb lasts 10,000.
Because the parts are independent, you only need
to change the bulb part that fails. These bulbs
also meet the strict energy code in California.
CFLs Reduce Cooling Costs, Too
Since CFLs generate less
heat than standard incandescent
bulbs, your air
have to work
hard in the
Back to Top
Answer: Yes, three-way CFLs are available, and no, you usually
don’t need a special lamp. The three-way bulbs that
ramp up to the equivalent of a 150-watt incandescent can be
either circular or spiral. Both shapes are quite large. For bulbs
in that range, check to be sure they’ll fit the harp and shade of
Also make certain your three-way bulb is screwed in snugly.
Unless the contacts on the bottom of the bulb make solid contact,
your three-way bulb may work like a single-output bulb.
Plugging Electrical Leaks
Even when your appliances and electrical
equipment are turned “Off,” the truth is,
they’re still “On.” One-fifth of the energy
used by televisions, stereo equipment, computers
and even answering machines is consumed
while they’re in standby mode. One
solution to the leaking electricity problem is
to physically unplug appliances or turn them
off via a power strip when they’re not in use.