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[dhouston]

I've tested a few different controllers.  The thirstiest ones draw around 8 watts constantly.  Most are around 1-2 watts.  MOST LED bulbs are still greater than 5 watts, so there is a minor savings.

What controllers? How did you test them?

Long ago I tested several X10 devices including the LM465, CM11A, CM15A and none draw as much as you state. See...
https://www.laser.com/dhouston/x10-sig.html
Scroll down to X10 Module Phantom Power at the bottom of the page.

[dspiffy]

I've tested a few different controllers.  The thirstiest ones draw around 8 watts constantly.  Most are around 1-2 watts.  MOST LED bulbs are still greater than 5 watts, so there is a minor savings.

What controllers? How did you test them?

Long ago I tested several X10 devices including the LM465, CM11A, CM15A and none draw as much as you state. See...
https://www.laser.com/dhouston/x10-sig.html
Scroll down to X10 Module Phantom Power at the bottom of the page.

Everything from Casablanca InteliTouch to motion sensors from outside lights to photocells . . . basically anything in my house that electronically controls a light.  I wired each device into an amp meter and tested the current draw with the lights on and lights off.

[dhouston]

Everything from Casablanca InteliTouch to motion sensors from outside lights to photocells . . . basically anything in my house that electronically controls a light.  I wired each device into an amp meter and tested the current draw with the lights on and lights off.

That overestimates the wattage. You are measuring Volt-Amps. The Kill-a-Watt (and others) sample the voltage and current 4000 (or more) times per second and then average them to get an accurate measure of watts.

Here's a brief tutorial on the subject.
http://www.electronicdesign.com/energy/what-s-difference-between-watts-and-volt-amperes

[dspiffy]

Everything from Casablanca InteliTouch to motion sensors from outside lights to photocells . . . basically anything in my house that electronically controls a light.  I wired each device into an amp meter and tested the current draw with the lights on and lights off.

That overestimates the wattage. You are measuring Volt-Amps. The Kill-a-Watt (and others) sample the voltage and current 4000 (or more) times per second and then average them to get an accurate measure of watts.

Here's a brief tutorial on the subject.
http://www.electronicdesign.com/energy/what-s-difference-between-watts-and-volt-amperes

For most of the work that I do, I need amps, not watts, so I'm fine with simply multiplying by 120-- it's "close enough for jazz" as one of my mentors would say.

Still, I would be curious to determine the difference, especially in these tiny lighting circuits.

[dhouston]

For most of the work that I do, I need amps, not watts, so I'm fine with simply multiplying by 120-- it's "close enough for jazz" as one of my mentors would say.

Still, I would be curious to determine the difference, especially in these tiny lighting circuits.

Most of us pay our electric company for watts so understanding the difference between watts and volt-amps helps understand our electric bills and informs our opinions on the things discussed here.

And, these tiny lighting circuits can add some further complications as most only draw current for a small percentage of each cycle (60Hz) of the powerline.

The tutorial is brief and enlightening*. (*pun intended)

[JeffVolp]

For most of the work that I do, I need amps, not watts, so I'm fine with simply multiplying by 120-- it's "close enough for jazz" as one of my mentors would say.

The phase angle between the applied AC waveform and the current drawn is important.  If you take a simple line-rated capacitor - say 1uF - and put it directly across the AC powerline, you would measure about .045 amp, or a little over 5 watts with your simple formula.  But the capacitor doesn't heat up significantly, as it should if it were actually consuming 5 watts.  This is because the current and voltage are out of phase, and no "real" power is consumed.  Most X10 and other automation modules use a dropping capacitor in their transformerless power supplies, and a simple current measurement would not be accurate.

Jeff

[BackAgain]

Different but similar is the outside transformers for low voltage lighting.  I found that they draw considerable wattage on a Kill-A-Watt all day while the lights are off.  The transformer is powered with 110 to keep the clock and/or photocells powered.  Only the low voltage output is switched and the increased power usage isn't that much different unless you have a lot of incandescent lamps in place.  I switched all of those to LED also, so I wasn't using much power there.

I ended up putting in a photocell to control the outlet the transformer is plugged into so that the transformer is now off during daylight.

Now that I have AHP working again, I may try an appliance module or X-10 outlet to control power to the transformer.

[dspiffy]

For ****s and giggles, I got a Kill A Watt.  Here is what I've tested so far.

LED PAR bulb:  0.7a, 7w. 
LED candelabra bulb: 0.3a, 3w.
Flicker Flame bulb:  0.1a, ~1w.  Sometimes it doesnt even read the wattage.
X10 lamp module with LED candelabra bulb: 0.3a whether on or off.  3w whether on or off.
X10 lamp module with LED PAR bulb:  0.7a on, 0.3a off.  7w on, 0.3w off.
LED night light bulb:  0a, 0w.  I DID get a current draw on these with my conventional amp meter.  Dont remember what it was but it was tiny.
USB phone charger: 0w with no phone plugged in, 1.5w with a phone plugged in.  I forgot to measure amps.

[Brian H]

You may also want to look at the Power Factor.
I have seen some LED bulbs around the 0.50 PF.
That would explain why your conventional meter may read differently.