I've been shifting to LED light bulbs due to the energy savings but I've a question about the new smart bulbs that are controllable via Alexa etc.

These need to be kept "on" via the switch for them to respond to Alexa / Google etc. So what's the parasitic consumption and does it anywhere close to kill the energy savings advantage?

I mean say I use a smart LED bulb for 6 hours a day then during that time period the energy savings of LED kick in. But during the remaining 18 hours of the day when the light is in an "off" state but yet the smart bulb is essentially energized what is the power consumption? Somehow that does not seem to be reported anywhere. Is it negligible say compared to the 10 W LED "on" state consumption?

Any data?

Clarification: This isn't about being green for greens sake. If the power consumption is only a fraction of a Watt I've no interest in saving it. My question was mainly with the intention of figuring out whether it is a fraction of a Watt.

  • 9
    Savings advantage over what? A smart LED bulb isn't going to save power over a "dumb" LED bulb, but the difference between an LED and an incandescent is so huge that no amount of standby power would even come close.
    – JPhi1618
    Commented Sep 9, 2019 at 14:19
  • Related: diy.stackexchange.com/questions/32633/…
    – Machavity
    Commented Sep 9, 2019 at 16:30

2 Answers 2


The specs are out there, just not always so easy to find. For example, one Philips Hue is rated at 9.5W with max. standby of 0.2W. (Click "The bulb" on the right side under Technical Specifications).

Using this bulb as an example, if it actually uses the full 0.2W all the time, 18H x 365D x 0.2W = 1,314 Wh per year. If your electricity costs 0.10/kWh, that's 13 cents per year for the 18 hours of standby vs. $2.08 for the 6 hours of light.

  • 1
    Using those numbers, a 60W incandescent is more efficient if the bulb is lit for less than 6 minutes a day. (Of course, then you don't have the remote control ability.) Commented Sep 9, 2019 at 5:57
  • Thanks! Would the I2R losses in the conductors add much more to the actual bulb consumption? Or would that term cancel out in an apples to apples comparison? Commented Sep 9, 2019 at 7:43
  • @curious_cat I2R losses are proportional to the square of the current, so for tiny currents it will be neglible. Commented Sep 9, 2019 at 13:13
  • 5
    Why would incandescents even be on the table? Come to it, why would someone who cares about energy efficiency even remember what an incandescent is? This is like contrasting the CO2 output of two models of plug-in hybrid, but for a reference for normal, using a Stanley Steamer... Commented Sep 9, 2019 at 15:36
  • 1
    @Harper As someone who cares about energy efficiency, I bought my house about 3 years ago and the bathroom had 6 40-watt incandescent bulbs above the bathroom mirror and others scattered throughout the house along with CFLs. After replacing everything with LEDs we lowered our electric bill by about $20/month. I was able to actually see the drastic savings because we did not replace with LEDs right away.
    – MonkeyZeus
    Commented Sep 9, 2019 at 15:39

This is splitting hairs... The concept of "grey energy" for powering of parasitic devices is severely overblown. You cannot just shut down a power generation plant, the plant ITSELF is a "parasitic load" on the grid if nobody is using that energy. So worrying about fractions of a watt, even spread across the entire planet, is an exercise in futility compared to the major change from incandescent vs LED spread across the planet.

Besides, if YOU are worried about it, get off of your keister and walk over to the lamp to turn it off rather than having Alexa do it for you. Saves energy AND gets you some real exercise. Of course in getting up and walking to the lamp, you burn calories and raise your body temperature, which increases the room temperature, so when it's warm outside your air conditioning must work that much harder to remove that heat, consuming more energy, probably more than the smart bulb would have.

Ergo, the best method of saving energy is to sit still in the dark all day doing nothing...

  • 3
    A friend justified the eating of two chocolate chip cookies with his morning coffee, by saying that because he ground the coffee by hand with a hand grinder that consumed the calories added by the two chocolate chip cookies.... Sadly when he finally did the figures (2 mins hand grinding etc) the cookies provided much more calories... So the amount of energy expended by getting your butt off the chair to turn off the lamp may not be as much as you think...
    – Solar Mike
    Commented Sep 9, 2019 at 18:58
  • 2
    Started off well but became quite ranty... Commented Sep 10, 2019 at 1:33
  • 1
    I'm with you on this. If it's a fraction of a Watt I've no interest in saving it. My question was mainly with the intention of figuring out whether it is a fraction of a Watt. Commented Sep 10, 2019 at 2:27
  • 2
    "This is spitting hairs" No, splitting hairs.
    – Mast
    Commented Sep 10, 2019 at 7:14
  • At least it wasn't splitting hares...crazy rabbit. Commented Sep 10, 2019 at 21:10

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