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OpenEnergyMonitor now available - the ONLY energy monitoring solution you'll ever need!

OpenEnergyMonitor Review

Energy monitoring has always been an essential part of any Home Automation system and we even have a dedicated guide to show what's possible using Z-Wave and LightwaveRF technologies.

While individual appliance monitoring has been well catered for with all manner of sockets and modules available with power metering capabilities, "whole house" or "whole circuit" energy monitoring has always been difficult to achieve.  The same can be said for monitoring your alternative energy sources such as Solar PV.

Sure, your energy provider may well offer you a so-called "Smart Meter" but often this will just be an extension of their own billing and accounting system and will be built around proprietary technologies that you can't interface with from your Smart Home system.

That's where OpenEnergyMonitor comes in and we're pleased to announce that we've recently added one of their most popular device bundles to the site - the emonPi Solar PV - and we thought that we'd whip up a quick overview to let you know what it's capable of.

In the first instance, don't be fooled by the name "emonPi Solar PV", it's not just for monitoring Solar PV, it will monitor any two single-phase AC circuits using clip-on Current Transformer clamp sensors and can also integrate a utility meter via an optional optical pulse sensor.

The emonPi monitors your energy usage in real-time and samples the CT clamp sensors many times a second to give accurate and timely readings every 10 seconds.  It's even capable of knowing which direction the power is flowing in the circuit being monitored, something that's critical when it comes to needing to monitor your Solar PV production!

It has both local and remote data logging capabilities with Emoncms which is an open-source software suite for processing, logging and visualising energy and other environmental data. Emoncms gives you an easy-to-use web UI to create and manage your Inputs and Feeds which actually do the hard work of logging your data.

Emoncms Inputs & Feeds

From there you can create all manner of visualisations and graphs.

Emoncms Graphs

You also have the ability to create your own real-time display Dashboards!

And this is where you can get *really* creative, we probably have about 50 different dashboards in use because you can customise them to suit different devices - tablets, phones, TVs, PCs, etc - anything that can display a web page in a browser like IE, Chrome or Firefox.

Emoncms Dashboards

We've yet to find a browser that doesn't work to be honest, even the one on the Amazon Fire tablets works well.  We have one of those sat on our desk as a real-time permanently on display - it takes just a few watts to keep running and lets us monitor our energy usage on an ongoing basis.

Emoncms Amazon Fire

A recent introduction to the platform has been "Web Apps" which are pre-built Dashboards for common tasks such as monitoring your Electric, Solar PV or Heat Pump data.  These work well and are easy to setup and configure if your needs are simple or you don't want to faff around with creating your own Dashboards (although to be fair, it's pretty easy using the drag-and-drop interface).

Emoncms My Electric Web AppEmoncms My SolarPV App

Of course, nowadays everybody wants to be using native Apps on their phones and tablets, so it's good to see that OpenEnergyMonitor has got you covered there too with Apps for both iOS and Android.

Emoncms iOS AppEmoncms Android App

We've actually been using Emoncms for many years to log data from our various Home Automation systems as it's an incredibly flexible platform but it can be difficult to setup and get running yourself so just recently we took the plunge with some of the OpenEnergyMonitor hardware to replace some of our own home-brew solutions.

And we're so glad that we did, because it means we now have a system that just works perfectly, with no reliability issues or dubious data readings.  It also means that we no longer have to constantly tinker around with things to keep the system running - we're sure all you Aeon Clamp Meter users know exactly what we're talking about!

Of course we're only just scratching the surface on what the OpenEnergyMonitor system can do - the emonPi includes additional functionality such as MQTT, NodeRED and OpenHAB.  While these are beyond the scope of what we're covering in this mini-review, these extras make it trivial to integrate the emonPi into your wider Smart Home systems.  With the real-time data flowing every 10 seconds it's simple to create all manner of logic such as turning on appliances when there's excess energy being created by the Solar PV system or perhaps turning off non-essential devices when your battery storage system starts getting low on charge.

Don't forget to also check out the OpenEnergyMonitor web site itself as it's full of useful articles and there's a great community too which has been really helpful assisting us with some of our more challenging logging and graphing requirements.


So if you're looking to take control of your energy usage or want to replace an existing system that isn't quite performing how you need, take a look at the emonPI, we're pretty sure that you won't be disappointed!

By for now,


Author David Bell

About the Author

David Bell is the founder of Vesternet. As a contributing author on popular smart home topics including Z-Wave & Zigbee, he’s been cited in a multitude of popular websites, forums & articles over the past 10 years and continues to publish regularly on Vesternet.

With over 25 years in business, and 15 years in home automation, he also heads up all of Vesternet’s commercial initiatives throughout various online channels as an expert in sales, marketing & growth strategies.

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