Review: Sonoff Pow – WiFi power switch and monitoring

by @edent | # # # # | 2 comments | Read ~5,844 times.

The good folks at Sonoff have sent me a bunch of kit to review. See my previous review of the S20 WiFi plug.

This is the Sonoff Pow – a WiFi enabled in-line power switch.

Sonoff Product Image

Set Up

Wiring up the Pow is relatively easy. The cover to the terminal block is secured with a simple screw.

Sonoff Pow opened up

I found the opening a little cramped – but it’s easy to open up the entire unit. Which gives us a full view of the circuitry.
Sonoff Pow with cover off
There’s an unpopulated header on the bottom left – yup – this thing is hackable!

A reminder, working with electricity is dangerous – if in doubt, consult with a trained professional.

The latches on the terminal block are stiff, but that’s probably a good way to stop the leads from falling out.

Sonoff Pow wired up

Once wired up, and power applied, the LED starts flashing.
Sonoff Pow LED lit up

From there, you can install the Android app and connect the Pow to your WiFi.

In Action


You can buy the Sonoff Pow on Amazon UK for £14.

Buying direct from the manufacturer is around $11 + $4 shipping

If you splash out, you can buy the Sonoff G1 – which has a GSM modem built in. Add a SIM card and it will connect to GPRS. Only $20!


As with other Sonoff products, this is built on the ESP8266. As the manufacturer says:

Apart from traditional consumers, Sonoff Pow is a very exciting product for those into hacking, since four program ports have been reserved for burning external firmware. Now, isn’t that thrilling?

There are a range of firmwares available on GitHub, and YouTube videos showing how to take control of the device. There’s a burgeoning community of bloggers with some great tutorials – see Tinkerman and CNX Software.


As with the S20 plug, this is a great little unit. It’s easy to set up, the app works reasonably well, and it is dead cheap.

The power monitoring seem fairly accurate – it picked up the exact wattage of my lightbulb – and the timers worked.

As with the S20, its usefulness depends on the electronics you have at home. If you have devices which regularly need turning on and off from the mains, this is perfect. The addition of monitoring makes it useful for anyone energy conscious.

The app is adequate – not brilliant. There’s no public API – which is a shame – but you can rewrite the firmware if that bothers you.

Amazon’s Echo Smart Home doesn’t work natively with the Sonoff. There is a 3rd-Party Alexa skill – called eWeLink Fan. It’s not as easy to set up as a normal smart-home device, and judging from the comments on the Sonoff website suffers from some problems.

If you’re handy with wire strippers, it’s a great little gizmo. Ideally it would be built into appliances – but as a way to add IoT smarts to an old device, it’s pretty good buy.

You can get the Sonoff Pow on Amazon UK for £14.

Buying direct from the manufacturer is around $11 + $4 shipping

2 thoughts on “Review: Sonoff Pow – WiFi power switch and monitoring

  1. Sam Machin says:

    Ordered one of these to control the electric water heater at home, seems like a nice bit of kit, however slightly worried that even though it has the CE mark and it looks to be the correct one (not the fake ‘China Export’ version that was doing the rounds) there’s no Declaration of Conformity which I thought was required to be included in the box? Perhaps you could ask your contact at Sonoff about that?

    1. Terence Eden says:

      They have a bunch of CE certificates listed on their wiki –

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