What Size Power Station Do I Need?
Pick what you want to run and for how long. You’ll get the three numbers that actually matter — inverter watts, surge watts, and battery capacity — plus stations that clear all three.
Essentials
Refrigeration — surges
Heating & cooling
Kitchen — high draw
Home systems — big surges
You need a station with at least
Add devices on the left to size your station.
Sizing a power station, the right way
“How many watts do I need?” has three answers, and a station has to satisfy all of them. Buy on running watts alone and a fridge’s startup surge trips the unit; buy on power alone and you run out of battery in an hour.
- Inverter (continuous) watts — the sum of everything running at once, plus ~20% headroom so you’re not maxing the inverter. This is the floor for what the station can power steadily.
- Surge (startup) watts — motors and compressors spike 2–4× their running draw for a split second at startup. Your surge rating must cover your biggest single startup happening while everything else runs, or the station trips.
- Battery capacity (Wh) — running load × hours, divided by inverter efficiency (~85% for AC) and a reserve you don’t drain. This sets how long it lasts.
One nuance the sizing above is deliberately conservative about: cycling loads. A fridge or AC only runs part of each hour, so its real energy use — and the capacity you need — is often lower than a straight running-watts × hours estimate. Once you’ve sized here, the fridge-backup and runtime calculators refine it.
FAQ
What size power station do I need?
It comes down to three numbers, not one: the continuous inverter watts (your total running load plus about 20% headroom), the surge watts (enough to cover the biggest motor startup — fridges, pumps, and AC units spike far above their running draw), and the battery capacity in watt-hours (your running load multiplied by how many hours you need, after efficiency and reserve losses). A station has to clear all three. Add your devices above and the calculator gives you each number plus stations that meet them.
How do I know how many watts I need?
Add up the running watts of everything you'll power at the same time — that's your continuous load. Then find the single device with the biggest startup surge (usually a fridge, pump, or AC): its surge, on top of everything else running, is your peak requirement. Your power station's inverter rating must exceed the running total and its surge rating must exceed that peak, or it will overload and shut off.
What size power station runs a refrigerator?
A standard refrigerator runs at roughly 150 watts but can surge to 800 watts or more when the compressor kicks on, so you want a station rated for at least ~1000W continuous and ~1200W+ surge. For capacity, a fridge only runs about a third of the time, so a 1000-2000Wh station typically keeps one cold for many hours to a day. Use the fridge-backup calculator for a duty-cycle-accurate runtime.
Why does surge (startup) wattage matter?
Anything with a motor or compressor — refrigerators, freezers, pumps, air conditioners, power tools — briefly pulls two to four times its running watts at the instant it starts. If your station's surge rating can't cover that spike, it trips its overload protection and cuts power, even though the running watts looked well within range. Sizing for surge, not just running watts, is the single most common mistake.
What size do I need to back up my house during an outage?
For essentials during an outage — fridge, lights, phones, Wi-Fi, and a CPAP — a 1000-2000Wh station with a 1500-2400W inverter covers most of a day and can be recharged with solar. To run more at once, add 240V loads, or bridge multi-day outages, step up to an expandable 3000-4000Wh+ unit. Size it here first, then see our best solar generators for the larger options.