Many of the bulbs in our home have been switched to Fluorescent tubes or CFL, but these do not work with conventional X-10 modules.  Although some CFLs can be dimmed, none to my knowledge allow the trickle of current that enable the powering of a conventional/basic wired-in wall switch (referring to those that do not have a separate hot&neutral wire). They also sometimes do not turn off completely, and remain flashing at a low repetition rate.

We have a light fixture outside the back door that sees harsh conditions, and is usually unnoticed until we realize its filament is broken, so I decided to try an LED bulb in that location.  I needed one that sends light out omnidirectionally, and not like the reflector type that were the first kind of LED lights that appeared on the market.

Cree LED bulb

I found the above bulb at Home Depot, and it cost $12.97.  I did not expect it to work with the conventional X-10 wall switch, and on my way home from the Depot, I was thinking I would probably need to add a neutral wire to the wall switch to it to allow it get power.  Being a diode at heart, I did not expect the LED bulb to conduct very much with the wall switch in series in OFF conditions.  So when I came home and simply installed it into the holder, and it actually worked, I was quite amazed and pleased.  I am able to run the bulb as a normal incandescent.  Being an LED, it does not take time to warm up, and it can be easily dimmed.

The power consumption is 9.5 Watts, and we normally run the bulb about 8 hours a day since it is the only light in our rather dark back yard.  At $0.1/kWhr, the savings are $14.75/year.  One more thing to note is that this bulb is covered by a thin layer of silicone, which I scratched when using a razor to open the package.  So be careful with it.

If you have found other LED bulbs that work with the conventional/basic (no neutral wire) wall switch, please let me know, and I will include it on this page.  Final note.  The standard light bulb base is known as "A19".

Other bulbs
  • I tried a 60W-equivalent Philips 'SlimStyle' bulb, which looks like a flattened bulb (Model 9290002707).  It does not work as well as the CREE.  X-10 commands work with wall switch, but OFF is not completely dark.  The local pushbutton switch does not work to control the bulb.  Thus this bulb is not complatible with the X-10 wall switch.
  • The Sylvania LED bulb (40W equivalent), Model LED6A19/F, aka A-line Lamp is shaped like a regular bulb with no visible heat sink fins. The packaging states not dimmable, and indeed with the X-10 wall switch will flash at a low rate.  This bulb is also not compatible with the X-10 wall switch.
  • The OSRAM "Ultra LED" 60 W equiv bulb (8.5W actual 2700K color) is also not X-10 compatible (lamp does not shut off and prevents comm with wall switch).  It also does not dim correctly.  The lamp just turns on suddenly during the ramp up.

  • After I wrote this blog, I found this thread that mentions similar successful results with the CREE bulb I used.
  • CREE web page for their bulb.
Project Log
  • November 2013.  First bulb installed.
  • January 2014.  Bulb (outside application) has stopped working.  I replaced it with new unit.  We will see if this is a trend with the CREE bulb (cold temperature susceptibility).  (2020 Update: the replacement bulb has worked fine).
  • August 2014.  Tested Philips SlimStyle and Sylvania A-line bulb.
  • August 2017.  I took my test rig to Home Depot and set it up in a shopping cart.  This allowed me to test onsite all the LED bulbs.  Unfortunately I could find none that worked with the two-wire wall switch.
bulb test
  • 2018.  I bought a box of CREE LED bulbs on Ebay but when they arrived realized that they were different than the ones that work.
  • March 2020.  I threw in the towel and modified a batch of wall switches and added a neutral wire to them.  So now I can easily find bulbs by making sure they are dimmable.  Instructions on how to add a neutral are here.

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(c) Edward Cheung, 2020