Home Battery Backup Calculator

How Much Battery Backup Do You Need?
Pick the things you want to keep running during a power outage and how long you want them to last. We’ll size the battery and give you a cost range and product category to start with.
Or skip this and pick items individually below.
Window air conditioner unitsEach unit uses about 8 kWh per day if running constantly
units
Pick from common US household items. Watts and surge multiplier auto-fill from typical values; you can edit anything before it lands in your total.
Battery capacity needed
0 kWh
includes safety buffer
Estimated cost range
$0
installed
Recommended product category
Daily energy needs
Inverter sizing
Continuous power your inverter must handle—
Surge power for motor startup (refrigerators, pumps, AC)—
240V loads detected—
A backup power option: Jackery solar generators
Jackery makes portable solar generators with built-in battery storage, sized to keep essential circuits running through an outage. Worth pricing against a fixed battery install before you commit.
See Jackery solar generatorsAffiliate link: we earn a commission if you buy through this link, at no extra cost to you. It does not affect what we recommend.
Ready to compare batteries?
We’ll show you vetted options at your size and budget. No-spam promise: you choose who gets your details.
See real battery options now
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Not ready for quotes? Get the Battery Backup Guide
A free PDF covering battery sizing, top brands, installation costs, and the questions to ask before you sign anything.
Energy estimates use typical residential averages. Real usage depends on the size and efficiency of each appliance. Battery costs vary widely by brand, installation complexity, and whether you pair with solar.
Data last updated 2026-05-08 Refreshed daily from EIA & NREL
How we make money  ·  Methodology and sources
A backup power option: Patriot Power Solar Generator 2500X
The Patriot Power Solar Generator 2500X is a portable solar generator with built-in battery storage, designed to keep essentials running during an outage. It’s one option to consider.
See the Patriot Power Solar Generator 2500XAffiliate link: we earn a commission if you buy or request a quote through this link, at no extra cost to you. It does not affect what we recommend.

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