A US home battery is financially promising when conservative, degraded bill savings recover the final installed price comfortably inside the warranty. Resilience can add personal value, but it is not a bill saving.
Use your utility economics
The United States is not one electricity market. Retail rates, time-of-use periods, demand charges, net metering and export compensation can change materially by utility and state.
For a conservative first screen, use the import price avoided and subtract the export credit sacrificed when solar is stored instead of sent to the grid.
Limit savings to energy that can cycle
Charging is limited by available solar surplus and usable battery capacity. Discharge is limited by household demand. Then round-trip losses and annual degradation reduce the value delivered.
- Use actual solar exports where possible
- Estimate evening and overnight use
- Enter current import and export rates
- Run a lower-export case
- Compare recovery with the written warranty
Keep resilience separate
Outage backup may be the main reason to buy a battery. Value it explicitly as a household resilience decision instead of inflating the financial savings forecast.