Methodology & sources
We'd rather you trust this than take our word for it. Here is every input, what we do with it, and where it's soft.
What we use
- Appliance running + surge watts — standard appliance-wattage and generator-sizing charts plus common-appliance data. These are representative figures for a class of device; your specific model's nameplate is the authority. We track 32 appliances and cite the source on every page.
- Power-station specs — usable watt-hours, continuous output, surge rating, chemistry, and recharge, hand-tabulated from each manufacturer's published spec pages across 34 current SKUs from Bluetti, Goal Zero, EcoFlow, Jackery, Anker SOLIX. This structured cross-brand table is the work nobody else does for a sizing calculator.
- Duty cycles — for cyclic loads (fridges, freezers, pumps, AC, blowers) we apply a representative duty fraction so the watt-hour estimate reflects real energy use, not peak draw.
What we compute
- Running watts — the sum of running watts for everything on at once. A unit's continuous output must clear it.
- Surge watts — the worst single startup surge landing on top of the rest of the running load. A unit's surge rating must clear it.
- Watt-hours — duty-weighted average draw × hours ÷ a 90% usable reserve. A unit's capacity must cover it.
- Match & rank — the units that clear all three, smallest capacity first (we never oversell), with a step-up. When no single battery holds enough energy, we recommend expandable systems that meet the power draw.
What this is NOT
This is a computed sizing estimate, not an electrical guarantee. We don't measure your actual appliances, account for wiring, inrush variation between specific motors, altitude, temperature derating, or simultaneous starts. For anything hardwired, a transfer switch, a 240 V load, or whole-home backup, the figures here are a starting point — the work must be sized and installed by a licensed electrician. Always confirm appliance nameplate ratings and current product specs before you buy.
How we make money (and why it doesn't bend the math)
We earn brand-direct affiliate commissions when you buy a recommended unit through our links. Ranking is driven solely by computed fit and smallest-sufficient capacity — never by commission rate. Where two units are equally sufficient we may route the click to the better-paying program, but we never recommend a unit that doesn't fit, and we never hide one that does. See the affiliate disclosure.
Data vintage — station specs & appliance wattages compiled 2026-06-15 02:18 UTC. Scenarios tracked: 9. Informational only — a computed sizing estimate from published appliance-wattage charts and manufacturer station specs. It is not an electrical guarantee. For hardwired or whole-home backup, transfer switches, or any permanent install, consult a licensed electrician.