Hi All
I have just about got Home assistant running but I have no idea which plug in will enable me to add CTs so I can monitor power flows.
Guidance would be much appreciated!.
Why not buy smart plugs that have current, voltage and power monitoring built in. Otherwise you can build at a high cost and your personal time using CTs and ESPHome devices that can take the voltage from the CTs and track that with a lot of program done by you. Or if these are appliances Stove/Oven, Dryer, Washer, A/C unit with Furnace you can look at the Shelly devices like the Shelly Pro EM-50. For the whole house I use the Shelly Pro 3EM since my electric meter has no way to monitor.
You would use the Energy Dashboard built in to track all of it. But I also use PowerCalc for the Shelly devices to get the different time/date values (day, week, month, quarter, Year). The Shelly device use a steady increasing valve for monitoring current/power/energy.
Thanks for the quick reply, the Shelly looks like it a good way to go.
I’ll give that a go!
A very sophisticated solution is found as openenergymonitor.org
Hi Jonathan, welcome to the forum!
You might also be interested in this: Powercalc - Virtual power sensors
Well all your pointers have narrowed the issue down wonderfully.
I’m going for the openenergy option for the moment, I want to see what the panels are doing before I give them the first clean in years to see what the difference is after!
I don’t know if this is an option where you are but we have switched (obliged) to digital counters which have an option to add a low cost solution and read out the traffic instantly, locally which can be interpreted by HA.
They did send someone around to install a smart meter, which I am assuming has the facility that you describe, but he took one look and said he couldn’t do it!
Over here it’s called a P1 port, has a RJ12 (like a classic phone RJ11) connection to connect a dongle and that’s all we need.
These dongles can use Ethernet or WiFi to connect to your network and transfer data to HA.
I didn’t know any of that!
Sounds really useful.
You can learn as long as you live…
It makes more sense - if possible of course - to tap into your smart meter and with a minimal cost of material, transfer the readings to your HA and not use some extra devices.
Does your smart meter have a P1 port, or any other, you can connect to?
The guy said he couldn’t install it. It is an electronic meter , but not a ‘smart’ meter apparently.
No reason was given.
Are there no smart meters yet where you live?
Installing digital meter to this day and age without being smart?! 
Who is your power provider?
The digital meter has been there for years, pre ‘smart’.
Hi @jlu Not sure, if you settled on a solution yet, but I have one of these and I’m very happy with it:
6 CH Energy Meter Made For ESPHome | Athom
I also have a 2-channel one that works great.
Scottish power.
You have a lot of options to gather accurate power readings, some frightfully expensive, some free.
From the Scottish Power website, the following guide shows you what to expect should you switch to a smart meter, something that will become inevitable, and they are heavily pushing.
https://web-content.scottishpower.co.uk/files/pdf/terms-and-conditions/SMETS2_Smart_PAYGO_Aclara_elec_guide_Oct20.pdf
The Aclara SGM1412 meter consists of two parts, The communications hub at the top half (the Toshiba bit), and the actual meter below. A product and battery life of twenty years is predicted.
A detailed 108 page manual on the meter can be found at
The items of interest for home automation integration are the optical port using the DLMS/COSEM IEC 62056-21 optical protocol at 9600baud. Some utilities, especially in Europe (as mentioned by previous posters) have read-only enabled customer access for this and other connections such as P1, M-Bus and RS485. A cheap interface and the data is right there in HomeAssistant. Unfortunately, per NCSC requirements, this is disabled from the factory for Scottish Power. Cross that one off the list.
The meter also supports a home area network (HAN) that establishes ZigBee 2.4 GHz ZigBee Smart Energy 1.2 protocol connections between two devices, notably an in-home display (IHD) and the communications hub.
The HAN is established on digital radios compliant with the IEEE802.15.4 Smart Energy standard, but is not the ZigBee standard you use for your other home devices, so don’t get your hopes up your hub can be used to pair with your smart meter.
When available, your utility company provides an unique security code and has to remotely pair a HAN to your meter. The HAN can be used for direct reading from the meter itself, provided by a In-Home Display (https://www.scottishpower.co.uk/support-centre/my-in-home-display), or something like the Rainforest Eagle (https://www.rainforestautomation.com/rfa-z114-eagle-200-utility/), which is not cheap, but will give you exactly the same output the utility company is getting from your meter for billing purposes. You may have luck with disassembling the IHD and tapping into the internals and repurposing them for your own needs with a bit if reverse engineering, but that requires a lot of technical knowledge. This HAN option is the most accurate, as it directly uses the same information that Scottish Power uses to bill you, and it is in real time.
We get to the third option, the one that most people gravitate to when they add up the costs of the other options - the LED on the front left side of the meter face next to the display that has a pulsed output. This is common on nearly all smart meters, but may not have the same location. The pulse rate for the Adara meter is fixed at 1,000 pulses per kWh/kVArh - a nice round figure of one watt per pulse, though I have seen 800 and 1600 impulses too. The duration of each output pulse is approximately 25 milliseconds.
You can count this with many types of sensors/readers, some of which are described in these forums, using simple devices such as a ESP32, Arduino, Pico W, etc combined with a photodiode or phototransistor discreetly placed over the LED - BluTack works well if you don’t want to make a neat 3D printed mount. This integrates into your Energy dashboard in HomeAssistant, counting the pulses emitted by the meter to indicate energy flow.
The Glow GitHub - klaasnicolaas/home-assistant-glow: ⚡ The power of energy measurements in your house · GitHub is the one that will probably most interest you. See Energy Management in Home Assistant - Home Assistant too. ESPHome or Tasmota can be used to compile the firmware to connect this to your network.
The Energy Insights in the ScottishPower App mobile phone app goes via your utility website, accessing the data via the cloud, not reading directly from the meter like that IHD and Rainforest Eagle does. It relies on frequent updates reliably transmitted back to base - not always the case - sometimes interference giving queued data a rush when it eventually gets through.
Your utility may also have a data exchange gateway that you can access via an API and the cloud to download the data that has been transmitted from your meter to them. There are apps developed for many utility companies that you can find on HACS that show how this is done. I encourage you to contact them to bring them up to speed on how useful this can be for home users if they have not shown any interest in releasing this access.
Carefully look at the face of your existing meter. It may have a pulsing LED already, in which case the Glow should work, and you can adjust the impulses count in your setup.
Of course you can just meter your electricity flow independently, not using the Scottish Power smart meter at all, and there are many vendors that provide whole-of-house solutions to do just that, some as a DIN rail mounted device, some wired via CT onto your cables, etc. That was your initial question, but I thought you may wish to visit alternates that may be more accurate or far cheaper.
The counting pulse option is very accurate, as long as the detector unit is up all the time. They frequency of ESPHome updates and re-flashing can interrupt that process and so a few pulse counts can be lost. Your integration can be adjusted to bring the two figures in line manually should this occur, so you can match it to your bills. For live control of connected devices in your home based on instantaneous consumption feedback, it is measuring by the watt, a granularity often hard pressed to obtain via CTs slapped onto loose wires behind your switchboard and subject to interference, and not accurately calibrated.
Suggestion: Get the smart meter (free). Get the IHD if it is free too, just for comparison. Try the low cost Glow type option first, and if you are not happy, go for a CT solution.