Whole-House Battery Backup Without Solar: The Real Math

Most whole-house battery content assumes you're buying solar and backs into batteries from there. This page is for the other buyer: you want the house to stay on when ERCOT stumbles, you don't want panels (yet), and you want the 2026 numbers — including the one most guides haven't updated.

First, the correction: the 30% credit is over

For three years the whole-house battery pitch leaned on the federal Residential Clean Energy Credit — 30% back on any battery system of 3kWh or more, solar or not. Per the IRS's own page, that credit applies to property installed from 2022 through December 31, 2025. If you're installing in 2026, the discount pages are still promising doesn't exist. Run your math at sticker price; treat any remaining incentives as a state-by-state bonus to verify, not a 30% line item to assume.

What "whole-house" actually requires

Two things separate whole-house backup from a big power station and an extension cord: 240V output (well pumps, central HVAC blowers, and dryers live there) and a legal connection to your circuits. The connection comes in two grades:

The transfer-switch grade (~$314 + electrician). A 6-circuit manual transfer switch feeds your chosen essentials from any capable 240V source. Flip it during an outage, and the fridge, furnace blower, well pump, and lights run off the battery through the house's own wiring — no cords across doorways.

The smart-panel grade ($1,599 + install). EcoFlow's Smart Home Panel 2 backs twelve circuits with a 20ms automatic switchover and per-circuit control from an app — load-shedding the water heater while protecting the freezer, automatically. This is the battery equivalent of a standby generator's automatic transfer switch.

The 2026 no-solar builds

Essentials-plus, ~$2,700: an EcoFlow Delta Pro 3 ($2,399 today) into the $314 transfer switch. 4,096Wh, 4,000W, real 240V — roughly 45 hours of the fridge-CPAP-router load, or a day of realistic multi-circuit essentials. Expandable to 12kWh later.

Automatic whole-home core, ~$4,000 before install: Delta Pro 3 plus Smart Home Panel 2. Same energy, but the switchover happens whether you're home or not, and circuit triage becomes software instead of discipline.

The budget expandable path, from $899: a Jackery Explorer 2000 Plus with expansion packs added over time reaches 12kWh — days of essentials — without ever committing to panel-grade install work. It's 120V-only: fine for fridge/comms/window-unit backup, not for the well pump.

For scale: Generac's own installed-cost figure for a gas standby system is $8,000–$16,000. The battery builds above land at a quarter to half of that — the trade is finite stored energy versus indefinite gas supply, which is exactly the fork our generator vs power station guide walks through.

Refilling without the sun

No panels means your refill strategies are the grid and the forecast. Pre-charge to 100% when weather is inbound (LiFePO4 packs tolerate sitting full through a storm watch just fine); after the outage, a Delta Pro 3 pulls itself back from the wall in under an hour of grid time between rolling blackouts. Some owners add a small dual-fuel generator as a day-three bulk charger — run outdoors, 20 feet from the house — which turns a fixed battery budget into a renewable one without touching the roof. Size the battery first though: the calculator tells you whether you're a 4kWh household or a 12kWh one before you spend a dollar on switching hardware.