My bathroom has an old light fixture that uses 4 standard light bulbs.
 In order to get enough light, I've been using 100-watt bulbs -- but I
know this is dangerous and I probably shouldn't use over 60 watts.

I've been trying to find out a way to get more light in the room, and
have found lightbulbs called CFL -- Compact Fluorescent Light -- bulbs
that have a screw-in base to fit a regular socket.  There are some
that say they are only 25 watts, but give off light equal to 100 watts
of incandescent light.

Does this mean each CFL bulb is really only 25 watts and are
presumably safe to use in a fixture that says not to use bulbs over 60
watts?  Will the CFL bulb really give off as much light as a 100-watt
incandescent bulb?

Hello natalie5111,

Thank you for your question.

Depending on which experts you read, CFL lightbulbs may not be quite
as efficient as you state in your question, but close.

EnergyStar.gov has the following to say:
http://www.energystar.gov/index.cfm?c=cfls.pr_cfls

"Compact Fluorescent Light Bulbs

If every household in the U.S. replaced one light bulb with an ENERGY
STAR qualified compact fluorescent light bulb (CFL), it would prevent
enough pollution to equal removing one million cars from the road.
CFLs provide high-quality light, smart technology, and design,
requiring less while lasting longer than typical incandescent bulbs.
 
Earning the ENERGY STAR

ENERGY STAR qualified CFLs use 66% less energy than a standard
incandescent bulb and last up to 10 times longer. Replacing a 100-watt
incandescent with a 32-watt CFL can save you at least $30 in energy
costs over the life of the bulb.

ENERGY STAR qualified CFLs operate at less than 100F, they are also
safer than typical halogen bulbs, which are frequently used in floor
lamps or torchieres and burn at 1,000F. Due to their high heat output,
halogens can cause burns and fires. CFLs are cool to the touch.

Remember, saving energy prevents pollution.

ENERGY STAR qualified CFLs provide the same amount of light (lumens)
as standard incandescent bulbs, but have lower wattage ratings. This
means they use less energy and cause less pollution. If you are
unfamiliar with the best CFL wattage to use for your lighting needs,
always refer to the lumen, or light output on the product packaging as
your guide. For example, most 60-watt incandescents provide around 800
lumens, so look for ENERGY STAR qualified CFLs that provide 800 lumens
or more..."

The table on this page notes that 60 watt bulbs output approx 800
lumens while 100 watt bulbs output about 1600 lumens.

The Office of Energy Efficiency says:
http://www.eere.energy.gov/consumerinfo/refbriefs/ef2.html

"...CFLs have the following advantages over incandescent light bulbs
when used properly: they last up to 10 times longer, use about 1/4 the
energy, and produce 90% less heat, while producing more light per
watt. For example, a 27 watt compact fluorescent lamp provides about
1800 lumens, compared to 1750 lumens from a 100 watt incandescent
lamp...."

So, you can see the experts differ slightly in their ratings.

Since you are looking to increase he light output without overloading
your fixture, you should be seeking CFLs rated at 1600 lumens or more
and 25-30 watt CFLs should more than fill the bill. The page above
compares Incandescent and CFL bulbs as follows:

25 Watt Incandescent = 5 Watt CFL
50 = 9
60 = 15
75 = 20
100 = 25
120 = 28
150 = 39

And using CFLs will save money:


           27 Watt Compact Fluorescent   100 Watt Incandescent
 
Cost of Lamps        $14.00               $0.50
 
Lamp Life       1642.5 days (4.5 years)  167 days
 
Annual Energy Cost    $5.91               $21.90
 
Lamps Replaced
in 4.5 years             0                   10
 
Total Cost            $40.60              $103.55
 
Savings Over 
Lamp Life              $62.95                 0


They also note:

"...CFLs that work with dimming switches are now available. Most,
however, cannot be dimmed. You should check with the manufacturer for
dimming applications. Although most CFLs fit into an existing 3-way
light socket, only a few special models can light to more than one
level..."

So do be sure to pick the proper bulb for your needs.
 
GE also has an excellent page of FAQ's (Frequently Asked Questions) on
CFLs at this url:
http://www.gelighting.com/na/faq/faq_cfl.html

And other explanations are available, such as this from Energy
Federation Incorporated:
http://www.efi.org/products/lighbulb.html

"...For most people, 1,750 lumens of light is plenty of light for
tasks like reading. You can obtain this amount of light by using two
60 watt incandescent light bulbs (14.8 lumens per watt), one 100 watt
incandescent light bulb (17.5 lumens per watt) or one 25 watt compact
fluorescent light bulb (70 lumens per watt)..."


Search Strategy:

Compact Fluorescent Light

I trust my research has answered your question and will soon have this
fixture operating more brightly and much safer. If a link above should
fail to work or anything require further explanation or research,
please do post a Request for Clarification prior to rating the answer
and closing the question and I will be pleased to assist further.

Regards,

-=clouseau=-

Just the information I needed!  Many thanks, Clouseau!

Happy to be able to help, Natalie.

Thank you for the rating and tip.

-=clouseau=-