Shelly EM Accuracy

Last month I wrote about the new toy I added to my smart home here on Skye. The Shelly EM and the 120amp clamp. I spent a good hour Googling how accurate the device was and didn’t really find anything definitive. I suppose they can’t really claim anything in fear of comeback. 

But now I’ve had a full month of usage I can report that it’s pretty damn accurate. Now, there is a small caveat here. I put my meter reading in 90 minutes before the end of the day so there would be a Kw or so either side but, in a nutshell the Shelly EM came back with a reading of £223.43 minus the daily charge. I still can’t figure out how to include this. Anyway, including the daily charge it comes in a £240.27 which is only 30 pence out. I would say that’s pretty incredible. That’s an accuracy of 99.85%. So if you’re in the market for an accurate meter reader or you think your existing meter may be telling porkies, the Shelly EM is an incredibly accurate way to record energy usage.