What Size Portable Power Station Do I Need? (2026 Guide)

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It’s raining hard, the power has been out for an hour, and you’re standing in the basement listening for the sump pump that isn’t running. Upstairs, the fridge is full of the week’s groceries and someone needs their CPAP tonight. Most people only ask what size portable power station do I need at a moment like this. Let’s answer it before the next storm.

The short answer: add up the watt-hours your devices use (watts × hours), divide by 0.85 for inverter losses, and buy at least that capacity. Then check that the station’s watts, including surge, cover your biggest motor. For most homes that means 1,000 Wh for an overnight outage and 2,000 to 3,000 Wh for a full day.

Power station sizes at a glance

Size class	Usable energy (× 0.85)	What it handles well
About 250–300 Wh	About 210–245 Wh	Router and modem overnight, phones, lights, a CPAP for part of a night
About 1,000 Wh	About 870–910 Wh	A fridge for most of a day, or CPAP plus router and lights overnight
About 2,000 Wh	About 1,740 Wh	Most of a day of essentials; a sump pump through a moderate storm
About 3,000 Wh and up	About 2,600 Wh and up	A full day of essentials, a small window AC for several hours, heavy sump pump use

The sizing math, step by step

1. List what must keep running. Be honest: fridge, router, lights, phones, CPAP, sump pump, a fan or a small AC. Leave out the electric oven, dryer and central air; those need a generator or a whole-home battery.
2. Find each device’s watts. Look at the label or the manual, or plug it into a watt meter. If the label only shows amps, multiply amps × volts (120 in U.S. homes) for the maximum.
3. Multiply by the hours you’ll use it. That’s watt-hours (Wh). For fridges and freezers, which cycle on and off, use the daily energy from the ENERGY STAR listing or the yellow EnergyGuide label (annual kWh ÷ 365).
4. Add it all up and divide by 0.85. The inverter that turns battery power into wall-outlet power, plus the station’s own electronics, lose some energy. 85% is a fair planning figure. The result is the minimum capacity you need.
5. Check the watts. Add the watts of everything that might run at once. The station’s continuous rating must be higher, and its surge rating must cover the start-up of any motor or compressor.

To estimate runtime for one device: hours ≈ (capacity in Wh × 0.85) ÷ device watts. All the runtimes below use this formula. They are our estimates, not maker claims, and real results change with settings, room temperature and battery age.

How much power your devices use

Device	Watts while running	Daily energy	Source
Mesh Wi-Fi router	4.5 W (eero 6+) to 21.9 W (eero Max 7)	About 110–530 Wh over 24 hours, plus the modem	eero
CPAP (ResMed AirSense 11)	56.1 W typical, 73.2 W peak	About 450 Wh for 8 hours at the typical figure	ResMed user guide
Ceiling fan, high speed	About 30 W	About 240 Wh for 8 hours	ENERGY STAR median
55-inch TV	About 85 W	About 340 Wh for 4 hours	ENERGY STAR median
Top-freezer fridge	Cycles	About 1.0 kWh	ENERGY STAR median (363 kWh/yr)
Bottom-freezer / French-door fridge	Cycles	About 1.5 kWh	ENERGY STAR median (556 kWh/yr)
Upright freezer	Cycles	About 1.2 kWh	ENERGY STAR median (438 kWh/yr)
5,000 BTU window AC	About 350 W while cooling	About 2.8 kWh for 8 hours of steady cooling	ENERGY STAR (BTU ÷ CEER)
8,000 BTU window AC	About 530 W while cooling	About 4.3 kWh for 8 hours of steady cooling	ENERGY STAR (BTU ÷ CEER)
1/3 HP sump pump (Zoeller M53)	About 1,120 W (9.7 A × 115 V)	Depends on how often it runs	Zoeller rating

ENERGY STAR figures are medians of certified models in each category, measured in a standard lab test. Older appliances, hot rooms and frequent door opening push the real numbers up, so give yourself a margin.

Worked examples

Router and modem: about 250 Wh is plenty

An eero 6+ uses 4.5 W, and with a cable modem a typical home setup lands somewhere around 15 W (check your modem’s label). A 245 Wh EcoFlow RIVER 3 gives about 208 usable Wh, or roughly 14 hours. A station with a UPS mode can sit between the wall and the router and take over by itself when the power drops; EcoFlow rates the RIVER 3 at under 20 milliseconds and the RIVER 3 Plus at under 10.

CPAP: 300 Wh to 1,000 Wh, depending on the humidifier

ResMed lists the AirSense 11’s typical power consumption at 56.1 W, so eight hours is about 450 Wh, which needs roughly 530 Wh of capacity. A 1,024 Wh station covers about two nights. The heated humidifier and heated tube use much of that power. ResMed says that, in consultation with your doctor, you can skip the humidifier and heated tube to reduce power use on batteries, and it offers a DC/DC converter so the machine can run from a battery without an inverter. Philips’ DreamStation 2 manual warns that a battery may not support humidification. Talk to your doctor or equipment supplier before changing how you use your therapy, and know that makers differ: Jackery says its stations are not recommended for medical devices. More in our CPAP guide.

Refrigerator: about 1,000 Wh per day, plus surge

ENERGY STAR’s median top-freezer fridge uses 363 kWh a year, about 1 kWh a day. A 1,024 Wh station (about 870 usable Wh) keeps it running for about 21 hours by our estimate; a bottom-freezer model at about 1.5 kWh a day gets about 14 hours. A 2,048 Wh station roughly doubles both. The compressor needs a short burst of extra power each time it starts, so look for a surge rating well above the fridge’s running watts; the 1,000 Wh stations below list 3,000 W or more. Our refrigerator guide has more detail.

Sump pump: 2,000 Wh or more, and a big surge rating

A sump pump is the hardest common job for a power station. Zoeller rates its popular 1/3 HP M53 at 9.7 amps at 115 volts, about 1,120 W running, and retailers list its starting current at 25.9 amps, close to 3,000 W for a moment. How much energy it uses depends on how often it runs. If, in a heavy storm, it runs one minute out of every ten, that’s 2.4 hours a day, or about 2,700 Wh, which needs roughly 3,200 Wh of capacity. In a light rain it might run one minute an hour, about 450 Wh a day. Time your pump during the next storm to get your own number.

For a sump pump, choose a station whose continuous rating is comfortably above the running watts and whose surge rating clears the start-up: the EcoFlow DELTA 3 Max Plus (3,000 W, 6,000 W surge) or Jackery HomePower 3000 (3,600 W, 7,200 W surge) are good fits. Plug the pump straight into the station with its own cord; never backfeed through a house outlet.

Window air conditioner: 3,000 Wh for a few hours

Air conditioners are energy-hungry. Based on ENERGY STAR’s efficiency ratings, a 5,000 BTU window unit draws about 350 W while cooling and an 8,000 BTU unit about 530 W. A 3,072 Wh station gives about 7.5 hours of steady cooling from the small unit and about 5 hours from the larger one; the compressor cycles off once the room is cool, so real runtimes can be longer. A 1,000 Wh station manages only about 2.5 hours on the 5,000 BTU unit. Every model on ENERGY STAR’s current certified room AC list is marked as having a variable-speed compressor, which ramps up gradually instead of starting with a hard jolt, so an ENERGY STAR unit is the easier one to run on a battery. Cool one bedroom, not the whole house.

“2000W portable power station”: two different things

People searching for a 2000W power station usually mean one of two specs. 2,000 W of output lets you run bigger loads at once, such as a microwave or coffee maker alongside the fridge (check their labels, since heating appliances draw a lot). The Anker SOLIX C1000 Gen 2 delivers 2,000 W from just 1,024 Wh, while the Jackery Explorer 2000 v2 (2,200 W) and EcoFlow DELTA 3 Max Plus (3,000 W) pair that output with more battery. 2,000 Wh of capacity is about a day of essentials: by our math, a 2,048 Wh station runs a top-freezer fridge, router and a night of CPAP for nearly a full day. For outages, capacity usually matters more than output.

A whole outage day, added up

Top-freezer fridge (1,000 Wh) + router and modem for 24 hours (360 Wh) + CPAP for 8 hours (450 Wh) + ceiling fan overnight (240 Wh) + a few LED lamps in the evening (150 Wh) = about 2,200 Wh. Divided by 0.85, that’s about 2,600 Wh of capacity for 24 hours without recharging. A 3 kWh station covers it; a 2 kWh station covers most of it, and a few hours of sun on solar panels can make up the rest.

Our top picks by size

Prices change often. The prices below are what we saw at the maker or a major retailer in October 2026; check the current price before you buy.

Model	Capacity	AC output (surge)	Weight	Price seen
EcoFlow RIVER 3	245 Wh	300 W (600 W)	7.8 lb	about $249 (Amazon)
EcoFlow DELTA 3 Plus	1,024 Wh	1,800 W (3,600 W)	27.6 lb	about $669 (maker sale)
Anker SOLIX C1000 Gen 2	1,024 Wh	2,000 W (3,000 W)	24.9 lb	check price
EcoFlow DELTA 3 Max Plus	2,048 Wh	3,000 W (6,000 W)	48.7 lb	about $1,149 (maker sale)
Jackery HomePower 3000	3,072 Wh	3,600 W (7,200 W)	59.5 lb	check price

1. EcoFlow RIVER 3: best for a router and phones

245 Wh in a 7.8-pound box, with two AC outlets (300 W, 600 W surge), a 100 W USB-C port and a car outlet. It charges from the wall in about an hour and takes up to 110 W of solar. About $249 on Amazon in October 2026.

• Good: light, cheap, UPS under 20 ms, 3,000 cycles to 80% (maker).
• Watch out: 300 W limit; not for fridges or pumps.
• Best for: keeping Wi-Fi up overnight; phones and lights.

Check the EcoFlow RIVER 3 price on Amazon

2. EcoFlow DELTA 3 Plus: best 1,000 Wh station

1,024 Wh, 1,800 W (3,600 W surge), six AC outlets, a 56-minute wall charge and up to 1,000 W of solar (EcoFlow). Expandable to 5 kWh. About $669 on EcoFlow’s store (sale; list $799).

• Good: fast charging, room to grow, 4,000 cycles to 80%, 5-year warranty (maker).
• Watch out: a full outage day needs about twice the capacity.
• Best for: fridge or CPAP plus router through the night.

Check the EcoFlow DELTA 3 Plus price on Amazon

3. Anker SOLIX C1000 Gen 2: most output for its size

2,000 W continuous (3,000 W surge) from a 1,024 Wh, 24.9-pound unit. Anker lists a 49-minute full charge in its UltraFast mode (switched on in the app, battery above 68°F), 600 W of solar input and a 10 ms UPS switch-over.

• Good: runs heavier appliances than most 1 kWh stations; 4,000 cycles to 80% (maker).
• Watch out: not expandable, and 2,000 W drains 1,024 Wh in well under an hour.
• Best for: short bursts of cooking or tools plus everyday essentials.

Check the Anker SOLIX C1000 Gen 2 price on Amazon

4. EcoFlow DELTA 3 Max Plus: best for a sump pump

2,048 Wh with 3,000 W of output and a 6,000 W surge rating, four 20-amp outlets and expansion to 10 kWh with extra batteries. EcoFlow lists 0–80% in 64 minutes from the wall. About $1,149 on EcoFlow’s store (sale; list $1,599).

• Good: plenty of surge for pump motors; grows with extra batteries.
• Watch out: 48.7 lb; EcoFlow doesn’t state a cycle count on its spec page.
• Best for: sump pumps, well-stocked fridges, a day of essentials.

Check the EcoFlow DELTA 3 Max Plus price on Amazon

5. Jackery HomePower 3000: best for a window AC

3,072 Wh, 3,600 W (7,200 W surge), four 20-amp outlets and one 30-amp outlet, at 59.5 pounds. Jackery lists a 2.2-hour wall charge, 1,000 W of solar and a 20 ms UPS switch-over.

• Good: about 7.5 hours of steady cooling from a 5,000 BTU unit by our estimate; light for 3 kWh.
• Watch out: not expandable; Jackery rates it 4,000 cycles to 70%+.
• Best for: a cool bedroom overnight, full-day outage essentials.

Check the Jackery HomePower 3000 price on Amazon

Keep exploring

Start at our portable power stations hub, then see the best stations for home backup, for a refrigerator and for CPAP, or power station vs generator. Watts and watt-hours are explained in electrical energy, and all our reviews are in the portable power stations category.

Sizing questions

Is 1,000 Wh enough for a power outage?

For an overnight outage, often yes. About 870 usable Wh keeps a typical top-freezer fridge running for about 21 hours, or a router, lights and a CPAP through the night. For a full day of fridge, router, CPAP, fan and lights, you need about 2,600 Wh, or a 1,000 Wh station plus solar panels or a generator to recharge it.

Can a portable power station run a sump pump?

Yes, if it’s big enough. A 1/3 HP pump like the Zoeller M53 draws about 1,120 W running and close to 3,000 W for a moment at start-up, so pick a station with a high surge rating, such as 6,000 W or more. In a heavy storm, plan on 2,000 to 3,000 Wh or more per day, and time your own pump to refine the number.

Can a power station run a window air conditioner?

Yes, for a limited time. A 5,000 BTU ENERGY STAR unit draws about 350 W while cooling, so a 3,072 Wh station gives about 7.5 hours of steady cooling and a 1,024 Wh station about 2.5 hours, by our estimate. Because the compressor cycles off once the room is cool, real runtimes can be longer. Close the door and cool one room.

What size power station do I need for a CPAP?

Using ResMed’s typical figure of 56.1 W for the AirSense 11, one 8-hour night is about 450 Wh, so a station of about 530 Wh or more covers one night at that typical figure. A smaller 250–300 Wh station covers a partial night at that figure, or longer if you run without heated humidification. Ask your doctor or equipment supplier first.

Why do I only get about 85% of the rated capacity?

The battery stores direct current, and the inverter converts it to the alternating current your wall plugs use. That conversion, plus the station’s screen, fans and electronics, uses some energy. Planning on 85% is a fair middle figure. Devices that charge over USB-C or run on 12V DC skip the inverter and get a bit more.

Watts or watt-hours: which matters more?

Both, for different reasons. Watts decide whether a device will run at all; if your fridge’s start-up surge exceeds the station’s surge rating, it simply shuts off. Watt-hours decide how long it runs. Check watts first to rule models out, then choose the capacity that covers your hours.