Just as smart thermostats are muscling in on old-school programmers, smart plugs are having a good go at yesterday’s twiddly timer switches, allowing you to turn just about any device smart and control it remotely. We've rounded up a few of the market leaders and tested them out, to help make sure you buy the best.

If you're hoping to pick up some more smart home tech, take a look at our guide to all the best smart home devices, then look at our round-up of the best smart home deals to make sure you're smart about your spending too.

What is a smart plug?

Basically it’s a switch that you plug into a power socket, and then plug another device into so you can control it via an app on your smartphone or tablet over Wi-Fi, or with voice controls through Alexa, Google Assistant or Siri.

With the best smart plugs you can set schedules, monitor energy usage and find out which devices are used most often and when. Armed with such data you can start saving on your home’s domestic electricity usage. Sounds interesting, but is it really useful?

The not-very-smart traditional power timer switch is pretty handy at switching things like lights, kettles and fish tanks on at set times or intervals. You can buy an analogue timer switch for under a fiver, or get a fancy digital one for a few pounds more. 

The 'smart' switch is more capable, linking with a smartphone app for device control wherever you are with an internet connection. Say you stay out longer than you were expecting to (“Go on, just one more pint”) and really want a light on inside your house to pretend you’re home. With a dumb-ish switch you’re stuffed. With a smart switch you’re only dumb if you let your phone battery run out.

Tap the app, select the smart switch you’re after, and turn on the light. Bingo.

The only caveat is that it will only be useful for devices that can be left in the 'on' position, then switched on or off by controlling the power from the mains. Anything that requires you to still press an additional button on the device won't turn just because you've turned on the mains outlet, so a smart plug socket won't be any help.

If you want to find out more, we've rounded up the top 10 things you can do with a smart plug.

Energy monitoring

One of the more appealing functions of smart switches is energy use and cost monitoring. Not all switches offer this feature, but many do. Devices are often left on standby when not in use for large parts of the day, and standby use accounts for around up to 16 percent of the average electricity bill, reckons energy gadget maker Efergy. With a smart switch you can dramatically cut down on this wasted Standby time. Efergy’s Ego smart socket is especially clever at cutting back on Standby time.

And there’s enough on offer to save you time and effort, too, in the day. Fill your kettle or coffee maker in the morning, and turn it on via the app when you get out of bed so that it has boiled by the time you get to your kitchen. This might sound a very lazy use of technology, but it's a daily time saver – if you remember to fill the kettle the night before!

The ability to turn devices on and off via Wi-Fi from afar, plus on various timed schedules, is useful. Seeing the energy usage and costs of various devices could help you save money, and some switches can even monitor multiple devices on a single power strip.

Prices

Smart switches start at around £15/$15, and rise to around £55/$55, so they're not yet so cheap you can buy one for every appliance. But for those you really want to control from afar, it can be worth the outlay.

TP-Link Wi-Fi Smart Plug

TP-Link Wi-Fi Smart Plug

TP-Link's Wi-Fi Smart Plug is one of our top picks. For a start, it's only £29.99/$39.99 and second, it connects via Wi-Fi directly to your router. So it doesn't need a hub, nor does it need (as Elgato's Eve Energy does) an Apple TV or iPad for remote control away from home.

There are iOS and Android apps, but the icing on the cake is that it also works with Amazon Alexa and Google Assistant. That means - while at home - you can say, "Alexa turn on the xxx" and control your device hands-free.

Via the app you can create schedules as you can with Energenie's switch, turning the plug on and off as many times as you like, with different schedules for each day if you like. Using your location, you can also choose sunrise and sunset as triggers.

There's also a timer mode so you can turn the plug on or off after a preset time, which could be handy for a sleep timer or to turn off the TV once the kids have had enough screen time.   

For just a little more, you can buy the HS110 which is the same except that it also monitors the energy the connected device consumes. You see at a glance how many kWh the appliance has used so far today and how long it has been on. Tap on each and you get more detail, such as current power usage, plus totals and daily averages for the past week and month. (It's the same breakdown for runtime).

With a well-designed and good-looking app, no need for a hub and a decent price, the TP-Link Wi-Fi Smart Plug is one of the best you can buy right now.

D-Link Mini Wi-Fi Smart Plug

D-Link Mini Wi-Fi Smart Plug

As the name suggests, this is a smaller version of D-Links regular smart plug. The compact design will help you avoid the plug getting in the way of anything else around the socket and ensures you can get two on a double.

The design has also been simplified with single power button on the top and an LED indicator at the top-right.

Otherwise it works in the same way so it's incredibly easy to set up and you get Amazon Alexa, Google Assistant and IFTTT support along with options such as scheduling from the mydlink app.

The main thing we'd like is the option to add widgets to an Android device's homescreen to quickly switch the plug on and off without opening the app.

Energenie MiHome WiFi Smart Plug

Energenie MiHome WiFi Smart Plug

Energenie has a range of smart plugs, but most of them require a £69.99 hub that connects to your router. The new WiFi Smart Plug, however, doesn't. That's great news, as it will talk directly to your router via Wi-Fi.

It doesn't have all the bells and whistles of Energenie's Adapter Plus, which can monitor how much electricity is being used, but it does support Alexa, Google Assistant and IFTTT which are more useful features for a lot of people. It's just a shame the instructions aren't particularly clear on how to set up these features.

Another benefit is the Plug's diminutive size which is less conspicuous than most smart plugs and also means it shouldn't prevent you using adjacent sockets.

It uses the same MiHome app as Energenie's other products and, if we're brutally honest, it's one of our least favourite because of its clunky interface. Still, unlike some of the cheaper Chinese smart plugs you'll find on Amazon, at least the app is all in English. Also, don't mistakenly install Xiaomi's MiHome app: look for the Energenie one instead.

When you've added the Plug in the app you can tap ON or OFF to manually control the switch (even when away from home) but you can also set up timers. You’re free to create as many as you like, for multiple power cycles each day and different times on different days.

Another point to note is that the MiHome WiFi Smart Plug supports 13 amp devices, whereas some of the cheaper offerings are limited to 10 amps - or less.

At this price (you can buy it from Amazon), the foibles can be forgiven: it's great value.

D-Link Wi-Fi Smart Plug

D-Link Wi-Fi Smart Plug

D-Link's Smart Plug is a good-looking device which has a glowing oval which tells you its status.

On the right are three buttons: one to turn the attached device on and off manually, another to turn the LED on or off, and a third to reset the plug or use WPS setup with your router.

Setting it up is simple via the mydlink app. You scan a QR code in the quick setup guide, and the plug should be detected. Then you can pick which Wi-Fi network you want the plug to connect to: like the TP-Link, no additional hub is required.

There's support for Alexa, Google Assistant and IFTTT so you can control it with your voice, or get it to turn on and off based on other triggers via an IFTTT applet. 

The mydlink app lets you control the plug from anywhere, as well as giving you the option to set it to turn on and off on a schedule.

Efergy Ego Smart Wi-Fi Switch

Efergy Ego Smart Socket

The Efergy Ego smart switch (which you can buy from Amazon for £29.99, though it's not available in the US) can work like a regular timer, and also has the knack of switching devices on and off at random, which could be useful when you’re trying to give the impression that a home is occupied when it’s actually vacant for a long time.

Its smartphone or tablet app will show you the energy usage of a device or strip of devices, plus their estimated cost over a period of time. Isolate the worst culprits and you’ll soon be making sure they’re properly switched off when not required.

While it lacks WeMo’s handy Notifications feature, the Ego wins out with its ability to learn and turn off appliances automatically that have been on stand-by for too long

When the appliance, most probably your TV, is plugged into the Ego and is on standby you go to the Stand-by/Learn screen in the app. Press the learn button and the Ego stores that value. Then in the Standby feature you set an amount of time, so after 'x' minutes of the TV being on standby I want it to turn off at the mains.

There is a also a Group function for those who multiple Ego switches in their home. You can group them together and control them all from the Group/scene page. The best application for this is to have all appliances in one room in a group.

Like the WeMo, the Efergy Ego is reasonably inconspicuous but still a little too bulky to not get in the way of other sockets’ flick switches. It is taller than the WeMo.

No hub is needed, so the price is all you pay, and at £29.99 at the moment it's great value. 

Eve Energy

Energy

The Eve Energy is a smart switch which also monitors how much power the connected device uses over time. It's an Apple HomeKit plug which means it works only with iOS devices. However, this also means you can control it with your voice using Siri and that it benefits from the full encryption that HomeKit offers.

Rather than use Wi-Fi, the switch uses Bluetooth. This makes setup easy (and also means you don't need to have a hub connected to your router) but it does limit the range over which it can be controlled. It will work in most 'normal' UK homes, but if you want to control it when away from home, you'll need an Apple TV (3rd gen or later) or a spare home-based iPad (newer than iPad 2) running iOS 8.1 or later.

You can turn the switch on and off via the Apple Home app in iOS 10 or use the Eve app. If you're standing next to the switch, there's a button on top for manual control, too.

Setting up timers is possible using the Scenes tab in the app, but creating a schedule is needlessly complicated compared to other apps, such as TP-Link's. However, the Eve app is built to work with the whole Eve range - not just a smart switch - and you can make all the gadgets work together using Scenes. It's powerful, but could be easier to use.

It's fairly expensive, but if you already have an iPad or Apple TV for remote access and you like the idea of controlling it via Siri, it could be right for you .

LightwaveRF Smart Socket

Lightwave RF Smart Socket

Here's something slightly different: the LightwaveRF Smart Socket let's you replace the actual sockets in your home with smart variants, so you can avoid having bulky plugs sitting on top of your sockets.

The sockets are available in either chrome or white, so should fit most homes, and once you set them up with the Lightwave app they're compatible with Google Assistant, Amazon Alexa, and Apple HomeKit.

There are downsides of course - you'll need to actually install the sockets obviously, rather than just plug them in. They're not cheap either - it's £60 for a two-gang socket, and you'll also need to buy the LightwaveRF hub so it can communicate with your router.

The best bet is probably to buy one of the starter kits and commit yourself to slowly building into the larger Lightwave ecosystem of sockets, light switches, and smart heating products. Alternatively, Energenie offers smart two-gang sockets for about half the price, but you still need a £69.99 hub.