Calculate
How many batteries do you actually need? Pick the appliances you want to keep running during an outage and how long you want them to last — we'll size the battery bank, count the units, and estimate the installed cost.
Select appliances to size your battery.
Get battery quotes near me → Size the solar panels too →Battery backup is sized from the energy your chosen loads use in a day, not from your whole electricity bill. We add up the typical daily draw of each appliance during an outage, multiply by how many days you want to ride through without sun, then divide by the usable fraction of a battery (about 81% after depth-of-discharge and round-trip losses).
The result is rounded up to whole battery units. If you have solar, the panels recharge the battery every day the sun is out, so a system sized for "1 day" of loads can keep essentials running indefinitely through a typical outage — the autonomy figure is really about cloudy stretches and overnight.
Battery storage of 3 kWh or more was eligible for the 30% federal residential credit — but only for systems placed in service by December 31, 2025. For 2026 and later installs the residential credit no longer applies. Check your eligibility →
Getting a home battery quote from an installer takes time. For portable backup, essential-loads-only setups, or a stopgap before a full install, these brands ship direct: