A home can export more electricity than it imports over an hour and still draw power from the grid during that hour. Home Assistant’s Opower integration uses the utility’s separate import and export readings, where supplied, instead of treating the hour’s net balance as the whole story.
Contributor tronikos measured the difference on a PG&E NEM2 account for July 2026: the old hourly calculation counted 197.20 kWh of imports against the meter’s 219.67 kWh, about 10% too little. Calculating from daily net totals missed that month’s imports entirely. The separate readings matched the billing statement’s import and export totals.
The integration’s regular refresh recalculates the most recent 30 days automatically; older stored figures stay as they are. Utilities that do not supply both readings keep the existing calculation, and cost and compensation figures still use net consumption. silamon reviewed and approved the change.