Smart Plugs

Why add smart plugs to a home? Why complicate the act of switching things on and off at the wall? Glad you asked:

  1. I want to schedule devices that don’t have timers, or have timers that are so absurd to work with they might as well not have timers. a. I want to have the timers link up to all the other timed activities in my house, like the lighting. b. I want schedules that are tied to humans, not to time. If my daughter has gone to school or to a friends’ house, why is her heater on? If she has come home, why is her room still cold?
  2. Power consumption: I have a non-trivial power bill. This is in part because I own too many things, but it’s probably in no small part how they’re being used. It would be great to make decisions about what should and shouldn’t be turned on and when based on evidence, not hunches.

    HomeKit: Joys, Deficencies

Why the focus, you might ask, on HomeKit? The best thing about HomeKit is that it requires you to publish a local API, this ensures that it will keep working even if the service app goes away. Since one of the biggest risks with home automation via modern stacks is that the company gets bought up, shut down, loses interest in a product line and wants you to buy a new set of devices, this is, in my opinion, pretty crucial.

It does have a number of deficiencies, though; apart of the obvious iOS requirement (which the dedicated can work around with OpenHAB, HomeAssitant, and the like), HomeKit doesn’t (at least not published through the Home application) show you power consumption or anything even remotely clever along those lines, which is annoying.

Philips Hue Smart Plug

I’ve got a bunch of Philips lights. Like, so many I have two hubs (the vexing topic of which is a whinge for another day1); it might seem natural, therefore, to look into the Hue smart plugs as a way to automate power around the house. Unfortunately, while Philips make the most expensive device, they’ve also chosen to make by far and a way the least capable:

  1. The Smart Plug really, really, really wants to be a light bulb. This is a pain in the arse, because it wants to be turned on and off with the lights in the room. Which is, you know, not ideal if you want a heater overnight in your room, for example.
  2. The Smart Plug doesn’t have any power tracking capabilty. No monitoring, no price management, nada.
  3. There’s no clear indication as to the safe power load that you can run through it.

Now, to be fair, Philips are clear that this is a device intended to convert manual lights into managed ones, and they tell you so, but that seems a bit like telling you that you shouldn’t use cotton buds to clean your ears ha ha are you fucking kidding me, right? It’s even more bizarre when you remember that the whole thing with the Hue system is that you can buy bulbs that are drop-in replacements for lights that have socketed bulbs.

The plug, by the way, can’t act as a dimmer, either. You can, at least, run 2 kW through it safely. Or so I hear.

The saving grace of this device is that it can run with HomeKit. Not much of a grace, I guess, but there you have it; so I can, for example, have a teenager’s room heater switched off when she leaves the house. So that’s nice.

Probably the only thing that it’s got going for it is that it’s smaller than either the Eve or Cygnett devices. Still not small enough to fit side-by-side with anything else on a multi-plug (for example).

Regardless, this is easily the most rubbish item in the Hue line-up and I would avoid it like the plague.


So the Cygnett is cheap and cheerful, and comes from a company that appears to be a bit of a me-too gadget builder; moreover, they have their own app that requires an account, so presumably their smart devices are fully surveillance capitalism enabled, which is less than ideal. It was also an absolute bastard to get paired with WiFi (which it requires) - enough that after a day of trying, I gave up, and bought an Eve device. I came back to it a few days later, though, and managed to get it working but it is something of a shitty experience, nonetheless.

All those things aside, there are some things that it does well:

  1. It’s HomeKit compatible, so I can centralise my power on/off type routines.
  2. The app itself is quite nice.
  3. It shows detailed power metrics: voltage, current, watts being consumed; you can trigger alarms and actions based on maximum and minimum consumption, too, so you can alert if (for example) your freezer stops drawing power, or alarm if you see sustained high current. That’s very cool.
  4. It tracks power metrics over time, and accepts you plugging in a cost, letting you see your spend moderately easily. One caveat here is that there’s no forward cost estimation, which makes it less convenient to tune your house to improve your power footprint (and spend).

Eve Energy Smart Plug

Much like the Cygnett, the Eve Smart Plug offers power monitoring as a function; to work around the shortcomings in the Home app and HomeKit framework, Eve supply their own application, but unlike Cygnett, it is an overlay to the HomeKit functionality, and does not require a seperate account or such.

The Eve application is one of the best things about the device, I have to say:

  1. It offers much richer management of lighting than the Home app, with lots of colour choices.
  2. The performance is massively more snappy.
  3. The power management is so far ahead that it might as well be on another plant. As well as tracking the power use, and scraping power costs to let you keep the cost current (you can override this if the number is too far out), it supports hour-by-hour breakdowns of consumption, and most importantly, cost projections based on your consumption for the last minute, hour, or day.

That last one is key: it’s trivial to use this to see how you can tune the setup of e.g. a home theatre receiver to reduce your power footprint. You can drill into power history at different ganularity (hhourly, daily, weekly), and the projection can be based on the last minute, last day, or last week, so that you can easily see how any changes you make affect (for better or worse) the consumption.

It’s not all gravy, though. For one, these devices only support two modes of network interaction; one via Bluetooth, and via the Threads network2. Bluetooth limits you to being in range of an AppleTV or one of your devices for any integration with your home. If you have a Thread network it will join that, but realistically the chances that you do are approximately zero: unless you’ve picked up a Thread hub from Eve themselves, been one of the people to buy a HomePod mini or a second-generation AppleTV 4K, this means they are useless except when within a few metres of a TV or iPad in Home Hub mode.

There’s an even larger drawback with the Eve smart plug, though: it only supports an 8 amp draw on 240 V systems (about 1.8 kW), which I can only assume is a consequence of it being built for a US market, perhaps? Regardless, while this means it’s a great tool for tuning your power consumption, it’s crippled in its ability to manage some of your most expensive devices: it’s not rated to use with either of the 2 kW panel heaters in my house, for starters, as an example, and will likely hit problems with a number of other appliances (dryers, freezers, and so on). So that takes a little of the gloss off what is otherwise a fantastic device.


HomeKit really needs to lift its game here. Or perhaps the Home application does (actually, the Home application definitely does); the fact that everyone who wants to do anything beyond basic on/off ends up implementing their own layer on top is a pretty damning comment, and given that it offers vendors a way to hoover your data off into the distance, it undermines Apple’s privacy and security pitch that they’ve made with HomeKit; also, it’s just plain clunky. The Eve application offers much better control over lighting that Home (not hard, colouring in your bulbs with felt tip pens offers better control of colour that the Home application), but having my plugs split between the Eve app (for the best power monitoring and forecasting options) and Cygnett (for the highest current support in the plug) is a pain in the arse, as is the fact that the Cygnett has some power management options that the Eve (and Home) don’t.

That said, the most practical option with what’s available in my market is Eve for every socket that I want to monitor and manage the amount I spend that doesn’t use more than 8 amps, and a few Cygnetts for the rest. The Hues were a waste of money. Don’t buy them.

Going back to my objectives, though: it’s improved the ability of the house to react to the presence (or absence) of various family members. And to the second point, probably the best example is my home theatre. If you ask around, most people will tell you that an AV reciever costs a negligible amount to leave idling. With some actual metrics, I found that the power drawn by my powered speakers and my reciever is over $250 per year. My assumption was that this was the amps in the speakers idling.

I was wrong: turns out that that reciever accounts for over $200 of that. The class D amps in the speakers? Very little. The reciever which, let me note, isn’t actually running any speakers, so whose amplifiers are completely unused, sucks down almost $20/month in power when idling. So I fixed that - but if I’d taken a hunch-based, rather than evidence-based, perspecitve, I’d have been completely wrong.

  1. Or right now. You know, the rubbish thing about the Hue system is that each hub is pretty limited in the number of rooms, automations, and lights it can manage. Sure, it seems OK at the start, but when you look at the number of lights in your house, it will quickly become apparent that “fifty odd lights” is a synonym for “not many”; moreover, the Philips software can connect to multiple hubs, but you have to manually switch between hubs to manage the lights like a fucking cave man are you fucking kidding me? If you’re going to force me to have multiple hubs how can you not have the simple decency to present a unified view in your goddamned software? I even have to copy automations to each bloody hub!
  2. If you’re wondering “What’s a thread network? Why didn’t I know the second gen AppleTV 4K adds this?” Bravo, you and everyone else. Other questions are likely to be “does this mean we now have n+1 incompatible standards instead of n?”, “this is going to be as badly engineered as anything else for IoT, isn’t it?” and so on.