Wesley's Tool-Box

Home automation devices have to be on standby at all times to respond to commands. This means that the baseline power consumption will increase as more devices are added. So if you're installing them not just for convenience but for more efficient energy use, you have to be conscious of the level of power that they may entail.

Unfortunately, detailed power consumption data are not usually found in the technical specs, likely because they are not deemed important. I had to take individual measurements to get the whole picture, and here are the results for the HomeKit devices I have.

[ Terminologies & Explanations ]

Off: The device is connected to the power but is turned off (i.e. standby mode).
Min.: Device operating under the lowest power mode possible.
Max.: Device operating under the normal or highest power mode possible.
(Minimum and Maximum values are measured with no external apparatus attached.)
Rated: How much the the device is rated to draw electricity at maximum.

1. Or 220V mains. 1,800W for the U.S. mains (120V).
2. For the LED and CFL bulbs. 600W for incandescent and halogen bulbs.
3. The indicator LED light is turned off.
4. For the LED and CFL bulbs. 1,800W for incandescent bulbs.
5. Only one switch is turned on.
6. Steadily decreases to the stable level (9.2W) over the span of 30 minutes.

It became fairly evident that the consumption profile is quite different between manufacturers even though the devices serve essentially the same purpose.

Lighting is one of the first things to be considered for being controlled in a smart home because it's an essential part of a house, and the light bulbs can be replaced relatively easily. Therefore the solutions are abundant, and even in Korea where HomeKit-compatible devices are practically non-existent in the market, Philips Hue series of smart lighting stand out as the rare exception. Only a subset are officially imported, but the available ones are priced lower than the overseas market, so I was quite happy to buy them locally. To start things off, I bought a Philips Hue White and Color Ambiance Starter Kit and a Dimmer Switch four months ago.


The kit contained three 2nd generation Hue White and Color Ambiance light bulbs and a HomeKit-compatible Hue Bridge. Buying them individually would be noticeably more expensive, so it's indeed a good value. I should note that 3rd generation bulbs with richer colours in the green spectrum were already available in overseas markets, but they have yet to be officially available in Korea even at the time of this writing. In my experience, it's not a critical difference and the 2nd generation ones hold up just fine.