We are now faced with many choices
for light bulbs. Prices vary widely for not much difference in
light. Here a few things to know about the choices.
First, lumens are the new watts. Watts are power and lumens are
light. An old incandescent 60 watts is about 800 lumens of light.
The wattage does not matter and most of the comparisons regarding
electricity costs are measured over years, so not very consequential
in a monthly or annual budget. A 60W incandescent lamp may push 800
lumens, while a CFL only needs 15W and an LED only needs 10W to
produce the same lumens. (A 10W incandescent is a night light.) The
thing to remember is how bright you want your light to be. Look at
lumens below to get the correct amount of light from your new bulbs.
incandescent bulb
watts - lumens
60 - 800
75 - 1,100
100 - 1,600
150 - 2,600
Heat might not seem important, but with a number of lights burning,
it adds up, especially during the summer. One heat test - halogen
bulb, a type of incandescent bulb, measured 327 degrees. A Cree LED
downlight was measured 107 degrees and a Philips Par38 CFL measured
167 degrees. LEDs produce 3.4 btu's/hour, compared to 85 for
incandescent bulbs.
Bugs don't fly toward many LEDs, because bugs are attracted to
ultraviolet light and most LEDs do not give off this type of light.
LED are rated to last 50,000 hours, while CFLs are rated for 10,000
hours and incandescents are rated for about 1,000 hours.
LED bulbs turn on as quickly as incandescent bulbs and faster than
CFLs. LEDs produce roughly the same amount of useful light, but much
of that light is focused in one direction. LEDs typically shine up,
rather than in all directions like incandescent bulbs. Newer LEDs
can be omnidirectional, look for that word on the package.
Some LEDs do not dim well and tend to buzz or sputter when the
dimming is at half. Check the package to make sure the bulb will
work with a dimmer.
A new term to further confuse us is CRI, because of the number of
different light types. It did not make any difference in the past as
all lights were the same. CRI is color rendering index. The higher
the CRI, the better the color rendering ability. Light sources with
a CRI of 90 or higher are excellent at color rendering and should be
used for tasks requiring the most accurate color discrimination. CRI
is independent of color temperature, but I won't even go there. Too
much information.
When considering lighting, I usually think of CFL as meaning
'crap for light'. They take longer to turn on (it
typically takes 30 seconds to 3 minutes to complete), need more
energy to turn on, contain mercury, may leak UV radiation, do not
work well in cold conditions, produce artificial fluorescent color,
and are less efficient than LEDs.
Although initial price is still much higher, the price of LEDs is
coming down quickly. LEDs are down to $4.97 at Home Depot, a far cry
from the old $20 they used to cost. Bottom Line, let your old
bulbs burn out before you rush out to buy new "energy savers" the
price will likely be cheaper when you are ready to replace. Also,
higher lumens are brighter and higher CRI provides better color
discrimination.