Why does Giv data differ to Zoa?

GivEnergy data discrepancies

Cause 1 - Inverter overhead is excluded from GivEnergy's consumption figure

The GivEnergy portal's consumption metric only covers energy delivered to appliances. It excludes the energy used by the inverter's own electronics, the Battery Management System, and heat lost during DC-to-AC conversion.

Zoa accounts for these where data allows, which is why its consumption figure is typically higher. This gap compounds over time, a ~50W overhead equates to roughly 1.2 kWh/day or 36 kWh/month.

Cause 2 - Time zone difference during BST

Zoa displays data in British local time (GMT/BST). The GivEnergy portal uses UTC. During BST (late March to late October) this creates a one-hour offset between the two, causing hourly and half-hourly breakdowns to appear misaligned. Overall energy totals are unaffected.