Review: Plugwise Home Stretch 2.0 ZigBee Appliance Control & Energy Monitoring
Automated Home’s favourite contributing reviewer, Ant Skelton, has spent the last few week putting the Plugwise Home Stretch 2.0 kit through its paces. Here’s what he found…
In the box
The Home Stretch 2.0 kit comprises of 9 plug-in modules, the Stretch gateway itself, plus the usual brackets, screws and cables. The kit contains UK-spec plug modules, but infuriatingly the gateway’s power supply comes with a European plug, so you’ll have to go hunting for a wobbly euro adaptor. This seems to be a common theme with European manufacturers of Home Automation kit, but this is the first time I’ve seen two different plug standards shipped in the same product.
Eight of the plugin modules are identical (with white backs), and there is one special one (with a grey back) that has a real-time clock in it. It’s also the Zigbee controller, if you’re a Zigbee nerd. Each of the modules has a little sticker on with its unique ID, and there’s a duplicate sticker for each, which is a nice touch. Plugwise encourage you to download and print an inventory sheet to which these stickers can be attached so you can plan your installation.
There are no instructions in the box, but you can download the manual, or you can save yourself the effort and just download the app which will guide you through the installation process. Plugwise apps are available for iOS, Android, Windows and Mac OS X.
Plugwise recommend that you carefully plan and site your modules within 10m of each other throughout your home, but I opted instead to give it harsher test by building a righteous tower of Plugwise power, which is often a tricky test of radio performance, particularly during setup.
Installation is initiated by the app, which kicks off by asking you to enter the code on the front of the Stretch gateway into the app’s dialog. With that done, you have a choice of connecting the Stretch to your home network either via Wi-fi or Ethernet. I recommend Ethernet, as it’s a much simpler process. The Wi-fi setup involves the usual rigmarole of changing your settings to use the Stretch as an access point, entering your real access point settings, and then switching back again.
Once you’re paired with the gateway, it can join the Zigbee network, which you’ll be pleased to find has effortlessly configured itself while you were mucking about with access point settings. This is one of the great benefits of Zigbee over the older and more common Z-Wave technology. Having formed your network, you can move the modules around as much as you like, as long as each module can see at least one other, the network will self-organise.
At this stage in the installation the Stretch will go online and find any new firmware that’s available. While it’s doing that, you can admire the user interface. Plugwise have wisely used some sort of cross-platform UI toolkit to make their interface the same everywhere, the practical upshot of which is, you get to experience the same dreary, ugly interface everywhere. It looks like a web page where the stylesheets have failed to load for some reason. This also means you get clunky windowing and navigation widgets, which behave differently and are considerably clumsier than whichever native ones you’re used to.
And then, suddenly, you’re taken to the main appliance monitor page, which is a welcome (and, sadly, rare) exception. Here you get a circle for each of your modules, where a dot orbits at a rate proportional to the energy being consumed. Strangely, one of mine has gone green and is rotating backwards, apparently generating 1W, which is odd given that it’s a simple floor lamp, but it does give you an indication of the sort of interface you’d get if you had a PV generating set up.
You can also click on these circles to turn the relevant module on or off. One particularly nice touch is that you can use the settings to disable the turn-off-and-on-ableness, so that you don’t inadvertently deactivate anything from the app.
There is a sometimes a significant delay between the state of a module changing and it being reported to the app, as the above image shows. This seems to be more pronounced at startup, after a while things settle down a bit and modules respond within a few seconds.
At this point I redeployed the modules around the house, and the wireless networking performed flawlessly, seamlessly adapting to the changes in topology. I also took the opportunity to customise each of the modules using the settings panel. Here you get to choose from a wide variety of appliances to match the load under test, although they could do with adding a few more – I’ve had to put the Mrs’ hair straighteners in as an ‘air conditioner’ (see what I did there?)
Notice that you get different icons once you’ve changed the appliance type and that the circles go grey if an appliance is off-line. In this instance because the Mrs has unplugged them all as she’s afraid that I’m going to harangue her with graphs about how much energy her various appliances are using. It’s worth pointing out here that each appliance module (sorry, I should really be calling them “Circles” but the old X-10 ways are hard to shake) is rated at 3kW and 13A – it will handle high-power devices like kettles and electric hair-fettling apparatus with ease. There’s no switch to provide local control, but that’s a minor quibble.
Once you’ve got your appliances configured, the main monitor screen becomes a thing of beauty, and it becomes really quite absorbing watching all the little dots race around, even the living room lamp, bless it.
You can also configure your electricity tariffs, and your language and currency symbol. But not your date format, which means you’ll have to put up with US format dates, an odd choice for a European kit with UK modules.
At this point I discovered that there’s a web interface, which once enabled allows you to monitor the system from any web browser, provided it’s on your local network. Strangely I couldn’t find any way to do this remotely, but I’m sure there’ll be some cloud-based shenanigans along shortly. You can however flick a switch in the settings to allow the apps to work remotely. Bizarrely, the web interface doesn’t use the same ugly HTML based interface that the apps do, it’s got an entirely different UI of its own. It’s not exactly easy on the eye either, but it does offer more functionality like grouping your modules together in to named groups.
Once you’ve tired of watching all the dots spin around, you’ll want to head over to the graphs tab for some more energy monitoring fun. If you’ve just set the system up, you’re in for a disappointment, as there’s no data available yet. The clunky user interface doesn’t tell you this however, it just hourglasses. I can’t tell you how long it takes the modules to report in first time because I got bored and went and did something else instead, but it’s certainly within the hour. Once the system has bedded in, modules seem to report in every hour or so: that is to say, they report instantaneous changes almost immediately, but logging data is uploaded in chunks of one hour. I can find no documentation or web-page to verify this as fact, but that seems to be what’s going on from observation.
Once you’ve got some data to review, you can view usage and cost by the hour, day, week, month, or year, but the graph widget itself really is utterly horrible to use, and spectacularly counterintuitive. Taking the “hour” tab as an example: it will show you the usage per hour of the day for a given day only, like the first image above. If you don’t have data for an entire day though, it shows you a subset like the second image above. Can you zoom out to see the whole day? No, no you can’t. Can you zoom out to see the hourly usage pattern over a few days? No chance. You might think that that little zoom slider at the top would help, but that just makes the circles at the top smaller, i.e. it only affects the vertical scale.
This would be useful on a small display like an iPhone in landscape mode, but for some reason it’s not available on the iPhone app, meaning the actual interesting graph data takes up a tiny fraction of the available screen real estate.
To view the settings from an earlier or later day, you can swipe the graph left or right, although the UI is once again tragic. A dreadful cheesy vertical bar lumbers across the screen while you’re swiping, the graph itself doesn’t move. The images above really don’t do justice to just how dire it is.
There’s another problem here: if you’re looking at today’s data, and you have historical data going back a couple of weeks, you’d expect to be able to swipe left a few times to look at it. But let’s say by some quirk of fate (more on which later) you didn’t get any readings at all yesterday. You might think you can swipe left, get an empty screen, and keep swiping left to look at the earlier data… but you’d be wrong. The app interprets a day with no data as the end of the line, and you get the dreaded “choose a larger unit of time…” message and that’s all she wrote. Either that or they throw away the hourly data after a couple of days have passed, I can’t quite tell.
Which brings me to that quirk of fate again. I reset the system a couple of weeks ago to get a nice clean set of data to provide screenshots for this review. Last week though, we had a brief power cut. When I came to generate the screenshots today, I discovered that I didn’t have quite as much historical data as I expected. Worse, I didn’t seem to have any live readings either, and I was no longer able to control the modules. Installing the Mac app led to all sorts of complaints about not being able to see the controller. After a bit of digging, it appears that the Stretch controller forgets all its network settings in the event of a power cut. This seems to me a major short-coming in a system whose sole purpose is to monitor power usage.
To end on a happier note, there is one more screen in the app that elevates itself above the standard user-interface tedium, and that’s the total power consumption screen, which you reach by tapping the unassuming little pie chart icon in the top left. What you get here is a pie chart that shows the aggregate total energy use, or the total per day, week, month or year. There’s a “now” tab too, but that never works and just hourglasses indefinitely. The “total” pie chart though, is exactly the sort of thing I wanted with which to berate the Mrs. Which is a pity, because (kettle aside) it shows that by far the biggest consumer is my gaming PC, even in standby.
In summary then, you get some capable power monitoring modules and bulletproof wireless networking, plus the gateway box, for about 35 sovs each. So there’s a solid foundation. The app software for the most part functions well, but is visually hideous, and the gateway needs some firmware fixes to survive a power cut, but this is all stuff Plugwise can address with future updates.
Alternatively, there seem to be a lot of Plugwise plugins for other systems like MicasaVerde, Domotica, HomeSeer etc. If you’re more of a DIY enthusiast there doesn’t seem to be an official API, but there’s an unofficial one here. Even with the current app’s (v1.6.17) less than handsome UI, it’s an extremely compelling system if you need to monitor lots of individual devices.