Whole-Home Backup

Whole-home backup is a battery storage configuration that powers your entire house — every circuit and appliance — during a grid outage, rather than only selected essential loads. It provides the same experience as having uninterrupted grid power, but supplied by your solar and battery system.

Whole-home backup requires a larger battery system and a more powerful inverter than critical-loads-only backup. While a single 13.5 kWh battery might sustain essential loads (refrigerator, lights, Wi-Fi, outlets) for 12–24 hours, powering an entire home — including air conditioning, electric water heater, dryer, oven, and EV charger — can draw 5–10 kW or more continuously, potentially draining the same battery in just 1–3 hours. True whole-home backup typically requires 2–4 batteries (27–54+ kWh) and an inverter system rated for your home’s peak demand. Some newer battery systems, like the Tesla Powerwall 3 (with up to 11.5 kW continuous output), are designed specifically for whole-home backup without a critical loads subpanel. The cost of whole-home backup ($20,000–$50,000+) is significantly higher than critical-loads backup ($12,000–$20,000), so homeowners should carefully evaluate which loads truly need backup power.