A 12,000 BTU ductless mini-split uses about 920 watts cooling and about 1,100 watts heating at rated conditions. Across sizes it ranges from a few hundred watts at low speed to about 2,500 W for large units, with little startup surge.
- Running watts
- 920 WTypical; 300–2,500 W across models
- Starting watts
- 1,000 WInverter compressors ramp up gradually, so there is little or no…
- Per day
- 5.5 kWh12 h of use, cycling
- Current
- 3.8 AAt 240 V while running
Figures checked against DOE, ENERGY STAR and manufacturer data on . Your model's label is the final word.
Watts by model and setting
Most mini-split models draw between 300 and 2,500 W while running; a typical one draws about 920 W. Assumes a 12,000 BTU unit averaging about half its 920 W rated draw over 12 hours; inverter units modulate rather than cycle.
- Capacity: 9,000-36,000 BTU single-zone units; bigger units draw more
- Inverter compressors modulate, drawing a few hundred watts at low output and more at maximum
- Efficiency: SEER2, EER2 and HSPF2 ratings are often far above central systems
- Outdoor temperature: heating in very cold weather pushes draw toward the maximum
- Number of indoor heads on a multi-zone system
Running a mini-split on backup power
This is a 240 V appliance. It needs a generator with a 240 V outlet or a transfer switch or interlock installed by a licensed electrician; most portable power stations only supply 120 V.
- Inverter mini-splits have a soft start, so they are among the easiest air conditioners to run on a generator or large battery
- Most mini-splits are 208/240 V, so they need a 240 V generator connected through a transfer switch or interlock by an electrician; some small units are 120 V
- Inverter electronics prefer clean power: use an inverter generator or a pure sine wave power station
- Never run a generator indoors or in a garage; place it well away from the outdoor unit and windows
Add it to the generator calculator
Questions people ask
Can a portable power station run a mini-split?
A 120 V mini-split can run on a large pure sine wave power station, and a 240 V unit needs a station or battery system with 240 V output; expect a few hours per several kWh of storage.
Do mini-splits have a big starting surge?
No. Inverter-driven compressors start slowly and ramp up, so starting draw is close to running watts.