Quick Answer
Match the load to the unit: a 300Wh power station covers phones, lights, and a basic CPAP for a night; a 1000Wh station runs a fridge for 10 to 15 hours or a CPAP for several nights; a 2000Wh station handles a fridge plus electronics for about a day; and a 3500W-or-larger generator is needed for motor loads like well pumps, sump pumps, and window AC.
Common Loads: Running vs Starting Watts
| Device | Running Watts | Starting (Surge) Watts | Smallest Unit That Runs It |
|---|---|---|---|
| LED lights (each) | 10 | 10 | 300Wh station |
| Phone charging | 5–20 | 20 | 300Wh station |
| Laptop charging | 50 | 50 | 300Wh station |
| CPAP (no humidifier) | 30–60 | 60 | 300Wh station (1 night) |
| CPAP (with humidifier) | ~100 | 100 | 1000Wh station (1 night) |
| Refrigerator / freezer | 700 | 2,200 | 1000Wh+ station (2000W surge) |
| Microwave | 1,000 | 1,000 | 2000Wh station / generator |
| Space heater | 1,500 | 1,500 | 2000Wh station / generator |
| Sump pump (1/3 HP) | 800 | 2,100 | 3500W+ generator |
| Well pump (1/2 HP) | 1,000 | 3,100 | 3500W+ generator |
| Window AC (10,000 BTU) | 1,200 | 4,800 | 5000W+ generator |
Values are typical and vary by model; check your appliance nameplate. A unit must handle both the running watts and the brief starting surge of motor-driven devices. CPAP draw is per equipment manufacturer ranges.
Recommended Size for Your Goal
| If You Want to Power | Recommended Size | Typical Runtime |
|---|---|---|
| Phones, lights, radio, basic CPAP | ~300Wh power station | 1 night CPAP / many phone charges |
| Fridge for a workday, electronics, CPAP for nights | ~1000Wh power station (2000W surge) | Fridge 10–15 hrs; CPAP 2–3 nights |
| Fridge + electronics for a full day, short microwave use | ~2000Wh power station | Fridge ~24 hrs |
| Well/sump pump, window AC, several circuits | 3500W+ inverter generator | Hours per tank; refuelable |
| Most of a home for days | 7500W+ dual-fuel generator | Continuous with fuel |
To total your exact load list and runtime, use the Generator Size Calculator, the Power Station Runtime Calculator, or the Battery Backup Sizing tool. See also the Generator Wattage Reference Table for the full appliance list.
Recommended Backup Power
Safety Warning
Never run a fuel-burning generator indoors, in a garage, or near windows; carbon monoxide is deadly. Keep it at least 20 feet from the house. Battery power stations are safe indoors. Have a licensed electrician install any transfer switch.
Important
Wattages and runtimes here are researched typical estimates that vary by model, battery age, temperature, and load. This is general planning information, not professional electrical or emergency advice. Confirm figures against your equipment nameplates and consult a licensed electrician for home connections.
Frequently Asked Questions
What size power station do I need for a CPAP?
A basic CPAP draws 30 to 60 watts and runs about one night on a 300Wh station. With a heated humidifier (up to ~100 watts) or for multiple nights, step up to a 1000Wh unit.
Can a power station run a refrigerator?
Yes, if it handles the roughly 2,000 to 2,900-watt startup surge. A 1000Wh unit keeps a fridge cold for about 10 to 15 hours; a 2000Wh unit closer to a full day.
What is the difference between watts and watt-hours?
Watts tell you whether a unit can run a device; watt-hours tell you how long. A 1000Wh station running 100 watts lasts about 10 hours, minus conversion losses.
When do I need a generator instead?
For motor-heavy loads like well or sump pumps and window AC, or to power a home for days, choose a 3500W or larger inverter generator.
Sources
- Generatorist: Generator Wattage Chart (manufacturer-aggregated running and surge data)
- Power station runtime = capacity (Wh) ÷ load (W), minus inverter conversion losses (industry standard)
- Generator sizing methodology: running watts + largest single surge