Measurement quality

Contributors use the Powercalc measure tool to control a physical device, wait for each state to settle and sample a compatible power meter. The resulting readings are stored as a fixed value, a linear model or a lookup table (LUT), depending on how the device behaves.

Profiles can record the meter, method, firmware, settings and measurement notes. These details help you judge provenance; their absence does not prove that a measurement is poor, but leaves less information to verify it.

LUT profiles receive a 0–100 smoothness score. The profile score is the lowest score across its LUT files, including subprofiles. This site groups that number into these bands:

The score describes how smooth and consistent the measured curve is. It does not validate meter accuracy. Fixed, linear and playbook profiles have no LUT curve and therefore no score.

The measure tool can read a Home Assistant power sensor that reports watts. Direct and alternative inputs currently include Shelly, Tasmota, Tuya, TP-Link Kasa, myStrom, manual entry and OCR; availability differs between the guided Home Assistant app and the CLI.

The same device can draw different power at different mains voltages. When available, a profile shows the observed voltage range and a nominal mains voltage. Compare these values with your local supply, especially when reusing a profile measured in another region.

A missing voltage means it was not recorded—not that the result is universal. The 120 V and 230 V library filters are broad context bands, not guarantees of compatibility. Dummy-load calibration for very low power also requires voltage readings.

Powercalc ultimately estimates consumption from device state, but most profile models are based on real measurements. When a profile explicitly marks standby power as an assumption, the profile page labels it estimated, not measured.

Very small loads are difficult for consumer meters to resolve. A documented estimate can be more honest than a rounded zero, but a direct measurement with suitable hardware is preferred. No estimate label should be read as a precision guarantee for every other value.

• The manufacturer and exact model ID match your device

• The measurement device, method and firmware are recorded

• The measured or nominal voltage fits your region

• The calculation strategy and available power range suit your use case

• Any value marked estimated is acceptable for your needs