This is a big load — about 6,667 Wh over 4.0 h. No single portable battery holds that much, but the expandable systems below meet the power draw (1,500 W running, 1,500 W surge) — add a battery module to reach the full watt-hours. This is the expandable-system territory most partial- and whole-home backup lives in.
The math
Running watts (everything on at once) = 1,500 W
Surge watts (worst single startup + the rest running) = 1,500 W
Average draw (cyclic loads counted by their duty cycle) = 1,500 W
Watt-hours = 1,500 W × 4.0 h ÷ 90% usable reserve = 6,667 Wh
1
EcoFlow DELTA Pro 3best expandable match
4,096 Wh4,000 W cont · 8,000 W surgeexpandable~2.5 h on this load$$$
A 4 kWh, 4,000 W (120/240 V) system built specifically for whole-home backup.
LiFePO4 · AC/solar/EV; expandable to 48 kWh · 113 lb
🔗 The "Check price" buttons are brand-direct affiliate links. Once our brand affiliate programs are approved these will earn a commission — at no extra cost to you, and it never changes which unit we recommend. Disclosure.
⚡ Duty cycle matters here. Resistive heat is the single most demanding common load — 1,500 W continuous drains any battery fast. We size watt-hours on the duty-weighted average (1,500 W), not the peak — so we don't oversell you capacity.
Can a specific unit run a space heater (1500 w)?
19 of the units we track deliver enough watts to run a space heater (1500 w). Check a specific one for the runtime and the full verdict:
What size power station do I need to run a space heater (1500 w)?
A space heater (1500 w) draws about 1,500 W running (a resistive load, so no real startup surge). So you want a unit with at least 1,500 W continuous output. For 4.0 h of runtime that's roughly 6,667 Wh of capacity — the EcoFlow DELTA Pro 3 is the smallest unit that clears all of it.
How many watts does a space heater (1500 w) use?
About 1,500 W while running. Resistive heat is the single most demanding common load — 1,500 W continuous drains any battery fast.
Sources: Space Heater (1500 W) wattage — Standard appliance-wattage / generator-sizing charts (representative values; verify your nameplate); station specs — manufacturer published specifications (compiled 2026-06-15; approximate). 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.