Windows Guide

Windows Energy Measurement

Enable hardware-accurate CPU power readings on Windows using LibreHardwareMonitor for CSRD-compliant certificates.

Measurement methods

The Serial Alice agent selects the best available method automatically, in priority order:

#MethodAccuracyRequirement
1 LibreHardwareMonitor Recommended Hardware-accurate LHM running with web server
2 psutil TDP estimation Default ±20–40% psutil installed (automatic)
3 GPU fraction fallback ±30–50% GPU energy available

For CSRD-compliant submissions, hardware-accurate readings from LHM are strongly recommended. Without LHM, the certificate will show "method": "psutil_tdp" instead of "method": "lhm".

Setup

1
Download LibreHardwareMonitor
Download the latest release from github.com/LibreHardwareMonitor and extract to any folder, e.g. C:\LHM\.
2
Run as Administrator
Right-click LibreHardwareMonitor.exe and select Run as administrator. Hardware power sensors require elevated permissions to read CPU registers.
3
Enable the web server
In LHM, go to Options → Remote Web Server → Run Web Server. Leave the port at 8085 (default). The Serial Alice agent connects to http://localhost:8085/data.json automatically.
4
Run the Serial Alice agent
Start the agent normally — no extra configuration needed. It detects LHM automatically and uses CPU Package Power for real-time measurements.

Verification

After issuing a certificate, check the measurement_window block. You should see "method": "lhm" to confirm hardware-accurate measurement is active.

FAQ

Is LHM required?
No — it is optional. The agent works without it using psutil TDP estimation as a fallback. LHM is recommended for CSRD-compliant reports requiring high-accuracy measurements.
Does LHM affect system performance?
No — LHM reads hardware registers passively. CPU and memory overhead is negligible (under 0.1%). It is safe to run continuously in the background.
What if port 8085 is already in use?
Change the port in LHM options, then set the environment variable SA_LHM_PORT=<port> before starting the Serial Alice agent.
How do I start LHM automatically with Windows?
Create a Task Scheduler task that runs LibreHardwareMonitor.exe with highest privileges at system startup. This ensures LHM is always ready when the agent starts.