Runtime reference: 20 household loads, calculated against three power stations

Specifications verified 2026-07-29 · Figures calculated, not measured · Method

Every runtime below is arithmetic you can reproduce: verified usable capacity divided by realistic device draw, with the working shown. Substitute your own appliance's wattage and the table still holds.

How we get our numbers: Every specification on this page comes from the manufacturer's published documentation or an authorized retailer's spec table — each one linked and dated at the foot of the page. Runtimes are calculated from those specs using the formula shown, so you can check them against your own equipment. The appliance wattages below are typical values for common household equipment, not measurements of your specific appliance. Full method.

The formula

usable Wh = rated Wh × 0.85 (inverter conversion loss) runtime h = usable Wh ÷ (device watts × duty cycle + 15 W inverter standby)

Three things trip people up. First, rated capacity is not usable capacity — converting DC to AC costs you roughly 15%. Second, duty cycle: anything thermostat-controlled (fridge, freezer, air conditioner, electric blanket) spends much of its time not drawing power at all. A fridge rated at 150 W running draws that 150 W for only about a third of each hour, which is why a 1 kWh battery keeps one cold overnight.

Third — and this is the one nearly every published calculation omits — the inverter consumes power just by being switched on, typically around 15 W, regardless of what is plugged in. On a heavy load that is noise. On a light, long, intermittent load it is decisive: over a 13-hour fridge run it costs nearly 200 Wh, about a fifth of the battery. Leave it out and your runtime estimate is roughly 30% too generous. The 15 W is an engineering estimate rather than a published figure — manufacturers seldom disclose standby draw — and we flag it as such wherever it appears.

The table

Load	Draw	Jackery Explorer 1000 v2 910 Wh usable	EcoFlow DELTA 2 870 Wh usable	BLUETTI AC180 979 Wh usable
Full-size refrigerator (modern, Energy Star) Compressor cycles; 150 W while running	150 W 33% duty	14 h	13 h	15 h
Older / larger refrigerator Pre-2010 units draw far more	250 W 40% duty	7.9 h	7.6 h	8.5 h
Chest freezer Better insulated than a fridge	200 W 30% duty	12 h	12 h	13 h
CPAP, no humidifier or heated hose The single best case for battery backup	30 W	20 h	19 h	22 h
CPAP with humidifier + heated hose Heating triples the draw	90 W	8.7 h	8.3 h	9.3 h
Wi-Fi router + cable modem	20 W	26 h	25 h	28 h
Laptop (charging)	60 W	12 h	12 h	13 h
Phone (per full charge) ~15 Wh per charge, not per hour	15 W	30 h	29 h	33 h
LED lamp	10 W	36 h	35 h	39 h
Box fan	75 W	10 h	9.7 h	11 h
Sump pump (1/3 hp), running Surge to ~2000 W on start	800 W 15% duty	6.7 h	6.4 h	7.3 h
Gas furnace blower + controls Heat itself is gas; the blower is the electrical load	600 W 50% duty	2.9 h	2.8 h	3.1 h
Microwave (1000 W class) Draws more than its cooking rating	1400 W	39 min	37 min	42 min
Coffee maker	900 W	60 min	57 min	1.1 h
Space heater (low setting) Resistive heat drains any battery fast	750 W	1.2 h	1.1 h	1.3 h
Space heater (high setting) At the limit of every unit here	1500 W	36 min	34 min	39 min
Window air conditioner (5,000 BTU) Surge on compressor start	500 W 60% duty	2.9 h	2.8 h	3.1 h
Television (55" LED)	100 W	7.9 h	7.6 h	8.5 h
Desktop PC + monitor	250 W	3.4 h	3.3 h	3.7 h
Electric blanket Thermostat-controlled	60 W 50% duty	20 h	19 h	22 h

How to read it

Red cells mean the load exceeds what that unit's inverter can deliver continuously. It will not run at all, regardless of battery capacity.
Surge is a separate question. Anything with a motor or compressor — fridge, freezer, sump pump, air conditioner — draws several times its running wattage for the first second or two. All three units here carry a surge rating between 2,700 W and 3,000 W, which covers a domestic fridge but not a well pump.
Phone charges are per charge, not per hour. A phone battery holds roughly 15 Wh, so the figure to divide by is capacity, not time.
Resistive heating is hopeless on battery. A 1,500 W space heater turns a 1 kWh power station into a 35-minute appliance. This is physics, not a product flaw — if you need heat during an outage, the answer is fuel, not a battery.

Where these numbers will be wrong

We would rather flag this than have you discover it during an outage:

Cold kills capacity. LiFePO4 loses usable capacity below freezing, and most of these units will refuse to charge at all below 0 °C. Garage storage in winter is a real problem.
Old appliances draw more. A fridge from 2005 can pull double what a current Energy Star model does. If your appliance has a nameplate, believe the nameplate over our table.
Battery age. These figures assume a healthy battery. At the manufacturer's stated end-of-life the pack holds 70–80% of what it did new.
Inverter efficiency varies with load. Very small loads are proportionally less efficient — running a 10 W lamp off a 1,800 W inverter wastes a surprising fraction on the inverter's own idle draw.

Working out your own number

Add up what you genuinely need to keep running, not everything you own. For most households an outage plan is: fridge, router, phones, a couple of lamps — around 60–80 W averaged over the day, which any of these three units carries overnight comfortably. Our sizing guide walks through building that list properly, and the refrigerator guide handles the load people worry about most.