What sensors/ software do you use to measure energy consumption?

Shelby's IoT devices. It is one of the fewest vendors who has Open API. Another vendor with Open API is Netio, but their products are expensive because they are meant for industrial usage.

Open API means you can get all the data and manage it locally, but it is over local WiFi/Ethernet instead of Zigbee.

For items attached to the UPS, I just monitor UPS load from NUTs.

For everything else not on a UPS (secondary PSUs from servers, monitors, and non-critical hardware), I use a mixture of HS110 and P110 TP-Link smart plugs. I had some issues with them becoming unresponsive though and the project to monitor HS110s is no longer updated and I don’t have the time to update it myself.

Tuya Smartlife Zigbee Energy Meter. 20$ for single sensor, there's also a version with 3 sensors for slightly more.

Data goes in HomeAssistant for quick monitoring and InfluxDB for further checks.

I compared it with readings of the energy company meter and it was within a 5% error over 6 months.

I personally use a combination of....

Per Circuit Monitoring: https://static.xtremeownage.com/blog/2023/home-solar-project-part-3-monitoring/

Sonoff S31s for individual devices: https://static.xtremeownage.com/blog/2023/sonoff-s31-low-cost-energy-monitoring/

A few HS300 Power Strips: https://static.xtremeownage.com/blog/2022/kasa-powerstrip-as-pdu/

TP-link wifi plugs with energy monitoring (theres a 4pack on sale right now too) and theres a github repo for a energy monitoring docker and also one for grafana that pulls from these tp-link smart plugs.

I have a Shelly Plug since a few weeks now, it's great

overall entire house: IoTaWatt. with this I monitor the power usage on every individual breaker in my house plus the 240VAC mains

for the home lab: combination of my APC network management card V3 in my UPS, which shows aggregate lab power usage but i also have a cyberpower pdu81003 that gives me outlet level on/off controls and outlet level power monitoring.

all of these report back to my InfluxDB database and i have nice grafana dashboards.

you can see more here

https://www.reddit.com/r/homelab/comments/om91wn/new_vs_old_homelab_setup/

https://www.reddit.com/r/selfhosted/comments/11yq6bh/home_lab_custom_webinterface_grafana_dashboards/

Kill-watt-meter

My UPS systems have built in monitoring.

IoTaWatt

Emporia. Fairly reasonably priced for what you get. I have 2 units. Main panel 16 circuit and sub panel 8 circuit.

I like the Sonoff S31 smart outlets flashed with tasmota, they're super easy to flash, super easy to configure, can communicate through mqtt (also easy to configure), have switching capability as well as measuring, and cost $7 a piece on Amazon.

zwave plugs in a couple of places (servers, media center) and zwave CT meter at the panel for the whole house. Metrics pipe to home assistant, then prometheus scrapes home assistant and grafana displays the data.

edit: also listen in on the electric company's (and gas and water) broadcast with rtlamr2mqtt

CTs would be the easiest option for longer term monitoring. Installation is non-invasive (to the wiring), and you can either buy a power monitoring system or design one yourself.

For something portable and non-permanent, a current clamp can be used to monitor a single device.

For a quick check, you could use a kill-a-watt

Because the only thing that matters at the end of the day is the overall total power consumption for my apartment I have an Emporia Vue sitting next to my breaker box graphing the data for all three phases. I spent a year logging values and then compared them to the bill (and monthly consumption numbers) sent out by my energy provider to know how those measurements relate to the actual billed amount since those sensors are never 100% accurate.

Look up "TAPO P-100" It's an IoT plug you can connect up with an app and it tracks your metrics as well as breaks up monthly cost once you throw costings at it

I splurged on an used APC metered PDU, which I then pull data from using telegraf which is stored in influx and displayed with grafana.

IOTAWATT

I use rpiPowerMon:

https://github.com/David00/rpi-power-monitor