Imagine calling a fluorescent bulb Tru Dim ;-)
(it's dimmable, apparently, and full of fun components)
Following on from the post about renowned lighting designer Howard Brandston's Mondo article, he has also updated his website commentary, with a letter to Consumer Reports (that they did not publish)
Excerpts, my highlights:
The design of lighting is the creation of a system to light a space.
When you take the total energy used to light many typical spaces, including the lighting controls, the total connected load and energy consumed when using incandescent light sources the result is, in many cases, equal to or more efficient than the new sources you are touting.
Then you make a serious technical error when you state that lumens measures brightness.
Lumens are a measure of radiant energy in the visible spectrum – not brightness.
More lumens do not mean more brightness or visibility – nor that you will prefer the light illuminating the scene or object it is falling upon. What is critical in this case is the Spectral Power Distribution of the light source.
In this case, when evaluated by most viewers, the incandescent light bulb wins – most of the time. That does not mean there are not several applications where alternative light sources perform perfectly well and are preferred. But to ban the incandescent light bulb is a serious detriment to the design of good lighting for many applications. People will sort that out
by themselves without the help of legislation....
Sincerely,
Howard M. Brandston, FIES, Hon. FCIBSE & SLL, FIALD, LC.
Comment
As covered previously here, Lumens are replacing Watts as the new standard for buying light bulbs by (supposedly) brightness...
CFLs and LEDs have spiky emission spectra, so strong brightness in single pure light colors might confuse the measurements, compares to the smoother, broader, light color emissions as with incandescents.
There are a lot of reasons why CFLs and LEDs seem dimmer than their lab rated values...
more on CFL brightness here (http://ceolas.net/#li15rbx),
and some additional notes on LED brightness (http://ceolas.net/#li15ledax).
5 comments:
CFLs dimmer than supposed
not 11 W but 15W same as 60w incandescent with light meter
http://www.telegraph.co.uk/earth/earthnews/6600015/Energy-saving-light-bulbs-get-dimmer-over-time.html
D Telegraph also on how CFLs get dimmer over time
"Traditional incandescent bulbs, which are being phased out of British shops, lose just a fraction of their brightness by the time they stop working, but energy-saving ones lose 22 per cent of brightness."
http://www.telegraph.co.uk/news/worldnews/europe/eu/6110547/Energy-saving-light-bulbs-offer-dim-future.html
Thanks Steven
Yes Savethebulb.org:
News Clippings
covers some of that too.
As quoted from a BBC article:
" The Lighting Research Center in the United States goes further.
“We believe in the divide by three rule,” says associate director Russell Leslie, who recommends a 20-watt CFL to match a 60-watt incandescent bulb. “The equivalent ratings you see on the box are usually got by testing in a laboratory environment.”
At home, brightness varies as conditions change. “A compact fluorescent light is designed to provide maximum light output at 25C, and when it gets hotter or colder than that, its brightness can be reduced.
“If your bulb is in a recessed fixture in the ceiling, and it gets warm, you might see a 10-20% reduction in its light output.”
And studies show CFL bulbs can get 20% dimmer over time."
and putting capping around cfl tubes or leds to make them look more like ordinary bulbs, and to spread the light better, also reduces the brightness!
jmc
also, even if they are are dimmable
1 they also cost even more than others
2 more fire risk with fluoros in dimmer curcuits
3 they give out a creepy kind of light when dimmed, not a warmer comfy light like with regular incand bulbs
Sarah Brescia
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