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EcoFlow DELTA Pro 3 sizing guide

A 4 kWh, 4,000 W (120/240 V) system built specifically for whole-home backup. Here's exactly what it runs, how long, and which outages it covers — computed, not marketed.

4,096 Whcapacity
4,000 Wcontinuous output
8,000 Wsurge rating
LiFePO4battery

AC/solar/EV; expandable to 48 kWh · 113 lb · 120/240 V AC, USB-A/C · expandable with add-on batteries.

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What the DELTA Pro 3 runs — and for how long

ApplianceRunningRuns it?Approx. runtime
Refrigerator (modern) 150 W (1,200 W surge) yes ~70 h
Chest Freezer 100 W (1,000 W surge) yes ~105 h
CPAP Machine (no humidifier) 40 W yes ~92 h
CPAP with Heated Humidifier 60 W (95 W surge) yes ~77 h
Oxygen Concentrator 350 W (600 W surge) yes ~11 h
Space Heater (1500 W) 1,500 W yes ~2.5 h
Window AC (8,000 BTU) 715 W (1,250 W surge) yes ~7.4 h
Window AC (12,000 BTU) 1,100 W (1,800 W surge) yes ~4.8 h
Gas Furnace Blower (1/2 HP) 800 W (2,350 W surge) yes ~9.2 h
Microwave (1000 W cooking) 1,200 W yes ~3.1 h
Sump Pump (1/3 HP) 800 W (1,500 W surge) yes ~23 h
Sump Pump (1/2 HP) 1,050 W (2,150 W surge) yes ~18 h
Well Pump (1/2 HP) 1,000 W (2,100 W surge) yes ~25 h

Runtime uses each load's duty-weighted average draw against 90% of the rated capacity — conservative on purpose. Cyclic loads (fridges, pumps) run far longer than running-watts × capacity would suggest.

Outages the DELTA Pro 3 covers

Power station for a home outage (fridge + CPAP + sump pump)
covered3,373 Wh
What size power station runs a CPAP all night?
covered356 Wh
What size power station / battery backup for a sump pump?
covered1,067 Wh
What size power station / solar generator for van life?
covered2,760 Wh
What size power station runs a refrigerator in an outage?
covered1,413 Wh
What size power station runs a window AC?
covered2,778 Wh
What size power station / solar generator for an off-grid cabin?
covered3,107 Wh

Common questions

What can the EcoFlow DELTA Pro 3 run?

With 4,000 W of continuous output and a 8,000 W surge rating, the EcoFlow DELTA Pro 3 runs refrigerator (modern), chest freezer, cpap machine (no humidifier), cpap with heated humidifier, oxygen concentrator, space heater (1500 w), and more. Its 4,096 Wh battery sets how long: a fridge for roughly a day, a CPAP for several nights.

How long will the EcoFlow DELTA Pro 3 run a refrigerator?

A modern refrigerator averages about 53 W (it cycles ~35% of the time), so the EcoFlow DELTA Pro 3's 4,096 Wh runs one for roughly 70 h before recharging.

Specs: Manufacturer published specifications (approximate; confirm on the current product page) (compiled 2026-06-15). Informational only — a computed sizing estimate from published appliance-wattage charts and manufacturer station specs. It is not an electrical guarantee. For hardwired or whole-home backup, transfer switches, or any permanent install, consult a licensed electrician.