How Many Watts Does a Window AC Use?
Verified July 2026 Manufacturer + DOE typical ratings. Methodology
Window AC wattage by type
| Size | Running watts | Compressor start |
|---|---|---|
| 5,000 BTU | 500W | 1,200W |
| 8,000 BTU | 900W | 1,800W |
| 12,000 BTU | 1,200W | 2,400W |
| 8k BTU inverter-type (U-shaped) | 550W avg | 700W (soft start) |
Heat emergencies are as dangerous as cold ones, and a single cooled room is the survival strategy. The sizing trap is the compressor start: traditional window units spike to double running watts, so your inverter needs 2x headroom. Two ways to slash the requirement: inverter-compressor window units (Midea/GE U-shape class) soft-start at ~700W and average ~550W - they nearly double battery runtime - and running the AC on a 60% duty cycle overnight (cool, coast, repeat) stretches capacity further.
How long real power stations run a window ac
Computed from each unit's rated capacity at 85% inverter efficiency and a 60% duty cycle (900W running, 1,800W start). Units that can't clear the start surge are excluded.
| Power station | Capacity | Estimated runtime | Price | |
|---|---|---|---|---|
| EcoFlow Delta Pro Ultra Longest | 6,144 Wh | 9.7 hours | $5,799 | Check price → |
| EcoFlow Delta Pro 3 | 4,096 Wh | 6.4 hours | $3,699 | Check price → |
| Anker SOLIX F3800 Plus | 3,840 Wh | 6.0 hours | $4,799 | Check price → |
| Bluetti Elite 200 v2 | 2,073 Wh | 3.3 hours | $1,699 | Check price → |
| Jackery Explorer 2000 v2 | 2,042 Wh | 3.2 hours | $1,499 | Check price → |
| Anker SOLIX C1000 | 1,056 Wh | 1.7 hours | $999 | Check price → |
| EcoFlow Delta 3 Plus | 1,024 Wh | 1.6 hours | $799 | Check price → |
| Bluetti AC70 | 768 Wh | 1.2 hours | $649 | Check price → |
⚡ Backing up more than a window ac?
Add your other appliances and outage length — our calculator sizes the whole load and shows exactly which units fit.
Size my full backup →Frequently asked questions
How long can a power station run a window AC?
An 8k BTU unit at 60% duty uses ~635Wh/hour: a 2kWh station runs ~3 hours, a 4kWh unit ~6.5 hours. An inverter-type U-shaped unit nearly doubles those figures.
What size power station do I need for a window AC?
Surge is the gate: 1,800W start needs a 2,000W+ surge inverter - the 2kWh class (Jackery 2000 v2, Bluetti Elite 200 v2) and up. For all-night cooling, 4kWh+.
Window AC or portable AC for backup cooling?
Window units - portable ACs are 30-40% less efficient at the same BTU, which directly wastes battery. The U-shaped inverter window units are the battery-friendly gold standard.
Keep reading
- Full comparison database — every spec, side by side
- Best-for guides — ranked picks by use case
- 2026 state incentives — what still pays after the federal credit