Fluorescent light bulbs get a bad, and badly outdated, rap. Technological
advances in the last twenty years have intro-
duced the compact fluorescent
light bulb (CFL) with electronic ballast and, in the process, have
eliminated three of the
four most common objections to fluorescent
Myth 1: Fluorescent lights flicker.
Yep, they used to. Modern CFLs, with their electronic ballasts, do
Myth 2: Fluorescent lights are slow to start.
While CFLs don’t start at full intensity like incandescent
bulbs, nearly all CFLs turn on (without flicker) instantly
full illumination very quickly. Of the nearly thirty different types
we’ve tested, all come on instantly at
close to full illumination.
Only the flood light styles start at noticeably less than full illumination,
but within 20 to
30 seconds they are at over 80% illumination. Interestingly,
we’ve come to prefer softer initial illumination. When
a room the slightly softer initial illumination is more welcoming,
and the CFL is easily at full
illumination by the time we begin any
Myth 3: Fluorescent lights are always cold-feeling and remind us
of office lighting.
Older, standard, long fluorescent tubes do emit a cool (bluish)
light (4,500+ Kelvin, see Kelvin definition below),
but today there
are CFLs in a complete range of hues, and many CFLs are available
that produce exactly the
same warm white light (2,700 to 3,000 Kelvin)
as traditional incandescent bulbs.
Myth 4: Fluorescent lights won’t fit in my fixtures, candelabra,
or recessed lights.
We agree that this can still be a problem in
certain situations. A CFL is often not an exact size substitute for
existing incandescent bulb, but a far greater range of sizes is
available than is generally realized. We’ve already
substituted standard, globe, flood, candelabra, three-way and dimmable
bulbs. To get the widest
range of shapes, it is often necessary to
shop online or at a lighting store.
The EPA’s Energy Star rating, when applied to CFLs, insures
the buyer of a CFL that it comes on instantly, comes quickly
illumination, is a warm/soft white hue (unless marked otherwise on
the package) and renders colors with excellent
accuracy. Are CFLs
the same as the traditional incandescent bulbs with which we are
familiar? No. But as discussed
below, they are significantly cheaper
to operate in the long run, are much better for the environment,
and enjoy a number
of other advantages.
Did you know...that a new Energy
Star-rated CFL bulb should last
between five and ten years?
In recent years, as the quality of CFLs has risen, their price has
dropped. Today, high quality 60-watt equivalent CFLs can
for under $2 in many stores or online. High quality recessed flood
lamp style CFLs run between $5 and
$10. Even though the cost of a
CFL is 1.5 to 4 times more than a standard incandescent bulb, CFLs
are a substantially
cheaper source of light. A typical CFL uses less
than a quarter the electricity of an incandescent bulb with similar
ness, and it lasts 6 to 12 times longer, meaning less time
and effort is spent buying and replacing light bulbs. There are
online calculators attainable to estimate the savings available with
The reason that standard incandescent (and halogen) lights are so
energy inefficient is that they produce their light as an
result of generating heat. In fact, 90% of the electricity consumed
by an incandescent bulb is used to generate
heat, while only 10%
is used to generate light. (Don’t get excited—incandescent
bulbs are NOT an efficient way to heat
an area; conventional heating
is much more energy efficient.) Therefore, in warmer seasons or locations,
lights make a space warmer than necessary and may drive
us to turn on the air conditioning, thus leading to even more
consumption. By contrast, CFLs (and all fluorescents) generate their
light more directly. 70% of the electricity a
CFL consumes is used
to generate light and only 30% goes to generate heat.
Below, we attempt to present a realistic picture of what a household
can save in energy costs and labor. The following
table gives the
details of the bulbs that were compared. We compared two bulb styles:
a standard light bulb (called an A-
19 by the lighting industry) and
a reflective recessed flood light (the R30, a mid-sized flood light).
Each of these is com-
pared to a commonly available GE™ light
bulb. In this comparison we assumed that flood lights are in hard-to-reach
and incandescent buyers would prefer the long-life version of the
GE™ flood light.
To simulate a realistic household situation,
we varied three cost assumptions in the data and included a labor
- First, we considered two types of bulbs, a standard
A-19 and a recessed flood light, and assumed a 70%/30% mix,
of the two types.
- Second, we used two electricity cost rates, the
national average cost ($0.11 per kilowatt hour) and a high cost
($0.18 per kilowatt hour).
- Third, we considered two residence
sizes, an apartment or very small house (20 bulbs) and a medium
sized home (50
- Fourth, we assumed that changing a light
bulb and remembering to buy replacement bulbs takes, on average,
The results are truly compelling and are shown on the bottom line
of the following table. The cost savings in the table
savings in electricity used and the bulb replacement savings, i.e.
since CFLs have such longer lives than
incandescents, their replacement
costs (over the life of the CFL) are usually cheaper. For an apartment
resident living in
an average cost electric market, converting just
20 bulbs could save, over the life of the CFLs, $1,400 and 10.5 hours
bulb maintenance and shopping. For an owner of a medium sized
home in an expensive electric market (NY, CT, MA, HI,
AL and parts
of CA and NJ), converting 50 bulbs could save nearly $5,200 and 26.3
hours of bulb maintenance. We
estimated the labor savings from using
CFLs because we wanted to show that the initial time required to
convert a house
to CFLs is easily offset by the labor savings from
not repeatedly changing the incandescent bulbs.
CFLs last between
5 and 10 years depending on average daily usage. Over the coming
5 to 10 years, electricity rates will
surely rise on average. As
electricity costs rise above the static rates used here, the savings
will grow accordingly.
For those who want more information:
Did you know...that if
every US household makes its next lightbulb an ENERGY STAR-rated
we will save more than $800 million on our national energy bill and
8.4 billion kWh of energy?
That's enough to power over 808,000 homes for one year - about the
number of homes in
Boston, Denver, and San Francisco combined.
The above analysis shows the savings that can come from converting
to CFLs. Using CFLs can also lower pollution
generally and greenhouse
gases specifically. The beauty and curse of electricity is that its
costs are usually invisible to
us. It arrives effortlessly in our
homes, and we seldom directly experience the pollution that results
from the burning of
fossil fuels (mostly coal) to generate it. Coal
is used to generate 51% of the electricity used in the US. Most generation
coal produces enormous amounts of carbon dioxide and significant
amounts of other pernicious pollutants.
The table below shows the reduction in atmospheric pollutants and
carbon dioxide that results from converting to CFLs.
Again we show
the results for an apartment (20 bulbs) and a medium-sized home (50
Converting to CFLs can help to decrease the amount of released atmospheric
carbon dioxide, the most prevalent human-
made greenhouse gas. Converting
just 20 incandescent bulbs to CFLs can help eliminate 12.7 tons of
carbon dioxide and
converting 50 bulbs can help eliminate the production
of nearly 32 tons of carbon dioxide over an assumed 7.3 year life
Sulphur dioxide and the various nitrogen oxides contribute to acid
rain and visible smog. Converting 20 bulbs to CFLs can
around 70 lbs. of each of these types of pollutants, and converting
50 bulbs can help reduce over 170 lbs. of
each, over the 7.3 year
life of the CFL.
Mercury, another dreadful pollutant, is a necessary, but minute,
component of each fluorescent light. The amount of
mercury in a typical
CFL bulb is about the size of the tip of a ballpoint pen or 5 mg.
This is one-fifth the amount found in a
watch battery and one-one
hundredth the amount in found in dental amalgams or older household
thermostats. But mercury is also released when coal and other fossil
fuels are burned to generate electricity.
To protect the environment, we want to produce the least amount
of atmospheric and landfill waste mercury. While incan-
contain no mercury, their excessive consumption of electricity, compared
to CFLs, results in greater mercury
waste. Even if burned-out CFL
bulbs are just tossed in the trash and their mercury is released,
the result is less environ-
mental mercury than using incandescent
bulbs for 3 or more years, due to the mercury released in burning
fossil fuel needed to power the less efficient incandescent
bulb. Therefore, since CFLs typically last six or more years,
CFLs generates less than half as much mercury as using incandescent
light bulbs - even without recycling.
Currently, federal law for hazardous materials does permit including
CFLs in household trash. However, as with all haz-
ardous waste, we
encourage appropriate recycling. This can be done by contacting your
local recycling center or, in some
instances, returning the used
CFLs to the store where they were purchased.
Did you know...that if
every household in the United States made the next lightbulb they
an ENERGY STAR, it would be like removing the pollution of 1.2 million cars for
Color. Light color has been the biggest impediment
to our own conversion to CFLs. (Size and fit were the other major
We understood little when we started, and so had to learn a lot
by experimenting with different products. However,
in the past
year, CFL labeling has improved, which helps new users with their
initial purchases. There are two general
metrics used in rating
the color of the light emitted by bulbs: color correlative temperature
(CCT) (stated in Kelvin) and the
color-rendering index (CRI). The
CCT or Kelvin number (ranging from 2,700 to 6,500) is a simplified
indicates the general color emitted by a bulb,
whereas the CRI (ranging from 0 to 100) indicates how accurately
emitted light renders the color of illuminated objects.
Kelvin numbers derive from the temperature (in Kelvin) of a theoretical
black body (made of carbon) as it emits different
colors of light
when heated to different temperatures. For our purposes, the following
table gives the three main Kelvin
ranges, with their characteristics
and general uses.
For home use, most individuals prefer soft- or warm-white (~2,700
Kelvin) in the living areas and bedrooms and cool
white (3,500 to
4,000, Kelvin) in the kitchen and in work and reading areas. The
CCT of an Energy Star rated bulb will be
between 2,700 and 3,000
Kelvin unless otherwise marked on the package.
The CRI is not directly related to the CCT. In fact, two bulbs can
have the same Kelvin number and different CRI
numbers. The CRI rating
indicates how accurately the emitted light renders the color of an
object. In light that has a CRI
less than 60, the finer features
of an object will appear somewhat washed out when compared to light
with a CRI rating
over 80. While the CRI uses a 100-point scale,
it is important to note that any number over 80 is considered excellent.
follow table summarizes the general range of CRIs:
The CRI of any Energy Star-rated CFL must be 80 or above. Should
you want a more technical/in-depth background on
either color temperature
or color rendering, visit:
Requirements for CFL Energy Star
Less than 1 second to start-up, less than 30 seconds to run-up to at
least 80% maximum lumen output. Greater than 6,000 hours average life
(5 1/2 years at 3 hours). CCT must be 2,700 to 3,000 K (warm/soft white)
unless marked on package. CRI must be 80% or greater.
Sizes and Shapes. While there are many color options
for each prospective bulb replacement, the size and shape of the
fixtures or locations may limit the available replacements. A key
to avoiding frustration is to know the style and
dimensions of each
bulb you wish to replace. Most stores carry the most common sizes
and shapes of bulbs. If you need
to replace a wide range of sizes
and shapes, you should consult various online lighting websites since
show images of the styles of bulbs and list the color
and wattage options within each category. A brief background on
and shapes can help orient the consumer.
The archetypal light bulb shape is what the industry calls a standard
A-19 bulb. It usually comes with the common screw
base called a medium
Standard Bulbs. Within limits, different wattages
can be placed in the standard A-19 shape. What makes a CFL compact
that a tiny fluorescent tube has been wound into a spiral to be able
to fit in the shape and space of a traditional incan-
bulb. Not surprisingly, therefore, CFLs are sometimes called spirals,
mini-spirals, or spring bulbs. The coiled
tube can take the place
of the standard bulb glass, or it can be placed inside a glass shell
of a standard looking bulb to
make it appear more conventional, in
which case there is a modest loss of luminance. In most cases, the
coiled tube of a
CFL takes up more space than the bulb of a conventional
bulb. So knowing the available space where the bulb is to be
used is important. However, the mini-spiral 14-watt CFL, the replacement CFL
for the common 60-watt conventional bulb,
takes up less space than the conventional bulb.
Globe Bulbs. Most conventional globe bulbs are
standard bulbs with an enlarged, globe-shaped glass. Since the glass
already enlarged in these conventional globe bulbs, the replacement
CFL globe is usually exactly the same size. In fact,
most globe bulbs
(incandescent and CFLs) are sold by the diameter of the glass globe.
Floodlight or Spotlight Bulbs. Many homes today
have recessed or built-in lighting that use a range of reflector
Reflector bulbs come in three primary sizes, R20, R30, and
R40, small, medium and large, respectively. Within each size
possible to get a range of different wattages. When other letters
are prefixed to a reflector bulb’s designation, they
to special aspects of the glass face or reflector shape. Common prefixes
include BR (bulbous reflector) and PAR
(parabolic aluminized reflector).
The PAR bulb represents the high end of reflector lights and is designed
both to provide a
focused light (with little light spread) and to
be used in damp locations (like showers or outdoors).
Candelabra and Tulip Bulbs. Candelabras, sconces
and smaller lamps often require a flame- or tulip-shaped bulb.
versions of these bulbs come with either frosted or clear glass bulbs,
with the latter meant to suggest a
more flame-like appearance. Also,
these bulbs come with both the small candelabra screw base and the
screw base. Presently, it is difficult for comparable
wattage CFLs to match the small size of these bulbs.
Three-way Bulbs. Standard CFLs do not work properly
when used in a three-way socket. A special, enhanced electronic
is built in to three-way CFL bulbs to make them work properly in
three-way sockets. CFLs are now available in a
full range of three-way
wattages and colors. These are most frequently available as spiral
or spring bulbs. They work
precisely like conventional three-ways,
but are somewhat larger. Higher wattage three-way CFLs are usually
extension clamps to raise the lamp shade slightly in order
to make more room for the larger CFL bulb.
Dimmable Bulbs. Many wattages and styles of dimmable
CFLs are now available. Even though dimmable CFLs gener-
well, most dimmable CFLs will not dim to as low an illumination as
a conventional incandescent bulb.
If you’d like a comprehensive review of many types of CFLs
available through a wide range of suppliers, visit this web
Other limitations and benefits. One limitation,
which was not mentioned above, relates to the use of CFLs with timing
CFLs usually work best with mechanical timers. Often, though not
always, electronic timers lower the voltage
supplied to a CFL.
In addition to cost savings, labor savings and environmental savings,
we find three other benefits to CFLs. First, thanks to
heat production, CFLs are far gentler to shades and fixtures than
the persistently hot incandescent bulbs. This
helps to protect fabric
shades from showing burn spots or becoming fragile over time. Similarly,
CFLs are much less likely
to cause browning or flaking on the decorative
frosting or coating of glass shades.
Second, unlike incandescent lights, at the end of their useful life,
CFLs don’t fail suddenly when the light switch is turned
Rather, they may take longer to reach full illumination, the level
of full illumination may become inconsistent or the
ballast may start
to buzz. This is an advantage because CFL bulbs give us some warning
instead of suddenly leaving us
in the dark.
Third, the slight delay-to-full illumination of CFLs is also a benefit.
While this did take some getting used to, we now
appreciate not being
blasted with full illumination upon entering a room. The initial,
near-full illumination, is easily suffi-
cient to move about in a
room. By the time we have set to any light-dependent task, the room
is fully lit.
In the first week of 2007, we attempted to convert all the incandescent
bulbs in Hal’s Deer Valley, Utah, home to CFLs.
The house was
completed about four years ago, two years prior to Hal’s
conversion to “green,” and included recessed
in nearly every room. When we began we had no idea of the number
or types of bulbs used in the house.
To start our conversion, we bought a sampling of lights from a nearby
Home Depot and from Wal-Mart as well as from a
couple of large online
lighting stores. With these samples in hand we experimented with
the color of the light, bulb fit and
start-up times. Based on this
pilot run, we made three determinations:
- We preferred the 2,700
to 2,850K (warm white) light in all locations except over the main
kitchen island where we used
a 3,500K (cool white) light.
- We could
live with—and actually preferred—the modestly
delayed start-up time of most CFLs.
- We could and would replace all
incandescent bulbs that had size suitable replacements. This meant
that only the three
interior chandeliers, several lamps and the
(occasionally used) halogen art lights would not be replaced.
Next, we inventoried all the lights to tally those targeted for
replacement. To our utter shock, we had 220 incandescent
lights. Of these 220 bulbs we targeted 193 (88%) for conversion.
Only the small chandelier and tulip bulbs were
not convertible, as
the fabric shades would not accommodate the larger CFLs.
In our experimental run, we compared a number of bulbs from different
providers with similar specifications. This allowed
us to observe
and then fuss over the mix of relatively small differences in bulb
size, color, and start-up times with equiva-
lent incandescent wattage
(i.e. light out in lumens). From the preferred bulb options, to keep
things simple, we reduced
our providers to two: the local Home Depot
and the online lighting store 1000bulbs.com. Home Depot is, of course,
known retailer. Of all the online lighting stores we inspected,
1000bulbs.com had the most user-friendly website, as well
sales staff and a low-price guarantee.
The result of our research resulted in the following selections,
shown with their targeted replacements. Due to the broad
range of 1000bulbs.com, the majority of our bulbs were bought online.
However, Home Depot had several very
pleasing high-quality CFL bulbs,
which as replacements represented an immediate upgrade in lighting
quality over the
older incandescent bulbs. These were the 60-watt
equivalent soft white mini-spiral and the 40-watt soft white fan
(used for make-up mirror lighting), both carrying the Commercial
Several points of learning are worth sharing. First, during the
pilot test, several bulbs buzzed audibly when installed.
happened we tested the same bulb in a different location and a different
CFL in the same location to determine
whether it was the bulb or
socket. In one instance, we determined it was the socket. In another
instance we determined
that the bulb was the problem and eliminated
that bulb from our list of candidates.
Second, several rooms had very high recessed lights that we misjudged
to be R40 when they in fact were the smaller
sized R30s. Given the
height above the floor of these recessed lights, we preferred higher
wattage R30 CFLs, i.e. 85-90
watt equivalent, in those lights. Since
higher wattage R30 bulbs (CFL or incandescent) are uncommon, this
left us with
only one option, which we got through 1000bulbs.com.
Third, a CFL’s speed to reach full illumination is temperature
dependent. In mountain climes (where the Deer Valley
house is), it
is not unusual for top-floor ceilings to be cold, and therefore CFLs
in such locations reach full brightness more
slowly than in other
rooms. So, if you need near full illumination quickly and your room
ceiling is under a cold or snow-
covered roof, you should consider
standard straight tube fluorescent or keep your existing incandescent
We admit the experimentation and investigation phases required organization
and discipline to complete. However, when
the time came to install
the CFL bulbs, the process was easy and left us with great satisfaction.
Overall, we are pleased
with the financial and environmental benefits
of using CFLs, and the family seems quite happy with the lighting
We now look forward to years of beautiful light with minimal
- Hal Hinkle, Kasia Duda