Five Percent: Conserve Energy

Climate Change Is Important: Energy Conservation is the First Step

January 3, 2006

Dimmable Compact Fluorescent Floodlight Redux

Category: Conservation,Cool Sites,Little Things,Save Electricity,Technology – Tom Harrison – 4:52 pm

In my recent post on Dimmable Compact Fluorescent floodlights I said I would try two new bulbs; both floodlights.

First the not so good. In the living room, we have R-30 floodlights in the ceiling on a dimmer. I tried Philips Marathon for Dimmable Flood. The French side of the box says it’s for R-30 lights, the English side says R-40, and reading more carefully, the page says R-40, so that was my goof (R-30 is available). The bulb is a standard CF bulb (well, standard dimmable one) with a reflector casing. With a little retrofitting, I got the bulb screwed in. Undimmed, I was pleasantly surprised at the warm light, almost the same as the existing incandescent. But as the light dimmed, it took on the characteristic blue tone of fluorescent bulbs. Also, at below about 1/2 dim, it turned off completely. For our use, this was not a good change, since we rarely have these lights turned up all the way and the dimmed light was pretty bad — dimmed incandescent lights use less power anyway. This bulb also is a 20W bulbs with 55W incandescent equivalent output, so not a big energy savings there, and pricey at $39 a pop.

The better was an indoor/outdoor PAR 38 flood (not dimmable), which we used to replace a motion-detector-activated light by our back door, outside. The shape of the bulb was very close to the regular bulb, and it worked without a hitch. Again, the light was pleasing (Warm White, 2700K), although not quite as bright as the replaced 75W bulb. The packaging said the (23W) bulb was equivalent to a 100W bulb, which I think might be a stretch. Still if it lasts 7 years, as the box claims, using 1/3 the electricity of bulbs that tend to last about 1 year, that’s a lot less waste, and a pretty good trade. Manufacturer is MaxLite, purchased from for $14.00.


  1. The r30 and the r40 mean the diameter. In technical terms 30 / 8 = 3.75 in

    Comment by Par — January 29, 2006 @ 2:17 pm

  2. If you still want to go with R40, you need to get 23w Greenlite brand R40 floods. They are 23w and give the equiv. lumens of 75 watt incandescent. Cheapest place on the ‘net is

    I have 14 of them in our home and they dim great — down to 20%. Just always remember to turn them on at full strength, THEN dim them down.

    Comment by Bill — October 25, 2006 @ 3:06 pm

  3. Bill — thanks! I tried the Greenlite bulbs as you recommended, and they are very nice.

    Comment by Admin — December 16, 2006 @ 12:29 pm

  4. We useMaxlite $40-23W light bulbs in our office. The light begins dimly, and then gradually brightens. One burned out, and I’d like to know whether it is safe to toss the old bulb in the trash or save it for hazardous material pick up. Can you advise?

    Thanks, Sandra

    Comment by Sandra — April 9, 2007 @ 1:20 pm

  5. Wow — great question. As it turns out, CFL’s use a small amount of mercury which would be released into the environment if just thrown out. Here’s a link to a page that answers the question better than I can:


    Comment by Admin — April 9, 2007 @ 6:04 pm

  6. we are energy saving lamp, dimmable CFL lamp supplier and exporter in China,
    our website for your checking
    any question, please ask us freely

    Best regards
    James Hong
    Lylight Electric
    Tel:0086 574 66856077
    Fax:0086 574 56887671

    Comment by James — November 3, 2007 @ 10:44 pm

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