What size power station do you need?
Short answer
For most homes, a 1,000 Wh power station with at least 1,500 W of output is the practical starting point. That covers phones, Wi-Fi, lights and a laptop overnight, a CPAP for two nights, or a refrigerator for most of a day. To keep a fridge plus essentials running for a full 24 hours, plan on roughly 3,000 Wh. Check output too: anything with a motor, like a fridge or sump pump, needs enough surge watts to start.
Two numbers decide the size
- Capacity (Wh) sets how long it lasts. Add up the energy your appliances use over the outage and divide by 0.85 to cover inverter losses.
- Output (W) sets what it can run at all. Everything running at the same time must fit under the continuous rating, and the biggest motor's startup must fit under the surge rating.
New to these terms? Read watts vs. watt-hours first.
Worked examples
These use typical appliance values from our wattage chart and assume 85% of the battery reaches your appliances.
| Scenario | Energy used | Capacity to buy | Output needed |
|---|---|---|---|
| One night of essentials Wi-Fi 12 h, three LED bulbs 6 h, laptop 4 h, phone charging | about 690 Wh | 1,000 Wh | 300 W or more |
| CPAP for one night 40 W for 8 hours, no heated humidifier | about 320 Wh | 500 Wh | 300 W or more |
| Fridge plus essentials for 24 hours Energy Star fridge averaging 60 W, Wi-Fi all day, lights, laptop, phones | about 2,370 Wh | 3,000 Wh | 1,500 W with 1,500 W+ surge |
| Fridge plus essentials for 3 days Same as above without the laptop, no recharging | about 6,400 Wh | 7,500 Wh, or solar or a generator | 1,500 W with 1,500 W+ surge |
For your own list of appliances, use the runtime calculator.
Size classes at a glance
| Capacity | Good for |
|---|---|
| 250 to 500 Wh | Phones, Wi-Fi, lights, a laptop, one CPAP night. Usually cannot start a full-size fridge. |
| 1,000 to 1,500 Wh | A fridge for most of a day, or several nights of electronics and CPAP. The sweet spot for most homes. |
| 2,000 to 3,600 Wh | A fridge plus essentials for a day or more, short sump pump or window AC use. |
| 5,000 Wh and up | Expandable home backup systems, usually with extra battery packs and a transfer switch or home panel. |
Ways to get by with a smaller unit
- Recharge during the day with solar panels, a car or a generator. See the solar charging calculator.
- Cycle the fridge: run it for a few hours, then unplug it while the doors stay closed.
- Use DC outputs for routers, CPAPs and phones where possible to skip inverter losses.
- Skip heating loads. Space heaters, kettles and hair dryers drain a battery in minutes.
Check before you buy
- Continuous and surge output, not just capacity.
- Pure sine wave inverter, especially for fridges and medical devices. See why it matters.
- Battery chemistry: LiFePO4 lasts much longer. See LiFePO4 vs. NMC.
- Maximum solar input if you plan to recharge from panels.
- Whether it can be expanded with extra batteries later.
Frequently asked questions
What size power station do I need to run a refrigerator?
At least 1,000 Wh of capacity and 1,500 W of surge output. That runs a typical modern fridge for roughly 9 to 21 hours. For a full day plus other essentials, look at 2,000 to 3,000 Wh.
Is a 1,000 Wh power station enough for a power outage?
For short outages and essentials, usually yes. It covers phones, Wi-Fi, lights and a laptop overnight, or a fridge for most of a day. Longer outages need a bigger unit or a way to recharge.
Can a power station run my whole house?
Portable units cannot. Large expandable home battery systems can cover many circuits, but running central air, an electric water heater or an electric range usually needs a standby generator or a whole-home battery installation.
Sources and method
Runtime figures assume 85% of battery capacity reaches AC appliances and typical US appliance ratings. See exactly how we calculate. Found a mistake? Tell us and we will fix it.