Two window air conditioners sit side by side on a store shelf. Both cool 350 square feet. Both produce 8,000 BTU. Both plug into a standard 115V outlet. One costs $300, the other $450.
If you are buying an air conditioner to run on a portable power station during a power outage, that $150 price difference determines how many hours of cooling you get from every charge. The reason comes down to two numbers most people never check: startup surge watts and running watts.
The Same 8,000 BTU, Wildly Different Power Needs
Here are three 8,000 BTU window air conditioners from our device database, with their verified running and surge wattage.
Midea MAW08V1QWT (inverter): 533W running, 800W surge.
LG LW8022IVSM (dual inverter): 516W running, 800W surge.
Frigidaire FHWC084WB1 (standard): 670W running, 2,010W surge.
Running watts are OEM-rated. Inverter surge (800W) is estimated at 1.5× running; standard surge (2,010W) is derived from the NEC 3× hermetic compressor standard. See our source hierarchy.
Running watts = the steady draw while cooling. Surge watts = the startup spike that can trip your power station’s overload protection.
The takeaway at a glance: The inverter AC typically starts on any station rated 1,000W or above. The standard AC needs at least 2,500W surge for a comfortable margin. Both run on mid-range stations, but the inverter stretches every charge 30 to 70 percent further.
The surge watts differ by 2.5 times: 800W versus 2,010W. That determines which power stations can start the AC with a comfortable safety margin. But the running watts tell the bigger story for battery backup: the Frigidaire draws 26 percent more power every second the compressor runs. Over hours of cooling, that gap compounds into significantly more runtime from the same battery with the inverter model.
How Inverter Compressors Work
The difference between an inverter AC and a standard AC is in the compressor, the motor that pumps refrigerant through the cooling cycle.
Standard compressor (fixed-speed)
A standard window AC compressor has one speed: full power. When the room temperature exceeds the thermostat setting, the compressor kicks on at 100 percent capacity. When the room reaches the target temperature, the compressor shuts off completely. This on/off cycling repeats throughout the day.
Every time the compressor starts from a dead stop, it draws a large burst of electrical current to overcome the inertia of the motor. This is the startup surge, also called locked-rotor amperage (LRA). For the Frigidaire FHWC084WB1, this surge reaches an estimated 2,010W, roughly three times the running wattage. The surge lasts only a fraction of a second, but the power station’s inverter must be able to deliver that peak or it will shut down with an overload error.
Because the compressor cycles on and off repeatedly, this surge event happens every time the compressor restarts. During a hot day, that can be every 10 to 20 minutes.
Inverter compressor (variable-speed)
An inverter AC compressor uses a variable frequency drive (VFD) to control the motor speed. Instead of switching between full power and off, the compressor ramps up gradually and then modulates its speed to match the cooling demand.
When the room is hot and needs rapid cooling, the compressor runs faster. As the room approaches the target temperature, the compressor slows down rather than shutting off. This continuous modulation eliminates the hard on/off cycling of a standard unit.
The startup behavior is fundamentally different. Because the VFD ramps the motor from zero to operating speed gradually, there is no sudden inrush of current. The Midea MAW08V1QWT surges to approximately 800W at startup, about 1.5 times its running wattage. The LG LW8022IVSM, with its dual inverter design, behaves similarly: approximately 800W surge on a 516W running draw.
This soft startup is why inverter ACs are considerably easier to run on battery power. The power station never has to deliver a sharp peak, and the variable-speed operation means lower average draw throughout the cooling session.
Impact on Power Station Sizing
When sizing a power station for air conditioning, two things matter: the surge rating determines whether the AC starts, and the running watts determine how long it runs.
Standard AC (Frigidaire FHWC084WB1)
Surge requirement: 2,010W. Applying the 1.25× buffer from our True Surge Protocol for compressor loads: 2,010 × 1.25 = 2,513W minimum peak capacity recommended.
Most mid-range and large power stations handle this:
Frigidaire FHWC084WB1 on EcoFlow DELTA 2 Max (4,800W surge). Margin: 2,287W above the 2,513W buffered requirement.
Frigidaire FHWC084WB1 on Bluetti AC200L (3,600W surge). Margin: 1,087W above the 2,513W buffered requirement.
Frigidaire FHWC084WB1 on Jackery Explorer 1000 v2 (3,000W surge). Margin: 487W above the 2,513W buffered requirement.
Frigidaire FHWC084WB1 on Anker SOLIX C1000 (2,400W surge). Passes the raw 2,010W surge but falls 113W short of the 2,513W buffered threshold. Works under normal conditions but leaves no margin for hot-day compressor stress.
The Jackery Explorer 1000 v2 at $799 can start the Frigidaire. But “starts” is only half the equation. At 670W continuous draw, that 1,070 Wh battery delivers just 1.1 hours of cooling.
Inverter AC (Midea MAW08V1QWT)
Surge requirement: 800W. With 1.25× buffer: 800 × 1.25 = 1,000W minimum peak capacity recommended.
Midea MAW08V1QWT on Jackery Explorer 1000 v2 (3,000W surge). Margin: 2,000W above the 1,000W buffered requirement.
Midea MAW08V1QWT on Anker SOLIX C1000 (2,400W surge). Margin: 1,400W above the 1,000W buffered requirement.
Virtually every power station in our database rated at 1,000W surge or above handles the Midea inverter AC. The only unit that falls below the buffered threshold is the Anker SOLIX C300, rated at 300W.
Both ACs start on most mid-range stations. The real advantage of the inverter appears after startup: how far each charge takes you.
Runtime Comparison
Surge determines whether the AC starts. Running watts determine how long it runs before the battery dies.
Frigidaire FHWC084WB1 (standard): 670W continuous when the compressor is on.
Midea MAW08V1QWT (inverter): 533W at rated capacity, but variable. During moderate demand, actual draw may drop to 300 to 400W.
On the Jackery Explorer 1000 v2 (1,070 Wh):
Standard Frigidaire: 1,070 × 0.70 / 670 = 1.1 hours
Inverter Midea at rated: 1,070 × 0.70 / 533 = 1.4 hours
Inverter Midea at moderate load (400W): 1,070 × 0.70 / 400 = 1.9 hours
On the EcoFlow DELTA 2 Max (2,048 Wh):
Standard Frigidaire: 2,048 × 0.70 / 670 = 2.1 hours
Inverter Midea at rated: 2,048 × 0.70 / 533 = 2.7 hours
Inverter Midea at moderate load (400W): 2,048 × 0.70 / 400 = 3.6 hours
The inverter AC provides 30 to 70 percent more runtime from the same battery, depending on cooling demand. Over an 8-hour period:
Standard Frigidaire: 670W × 8h = 5,360 Wh consumed.
Inverter Midea: 533W × 8h = 4,264 Wh at full load. At moderate load (400W average): 3,200 Wh.
The difference between 5,360 Wh and 3,200 Wh is 2,160 Wh, enough energy to run a refrigerator for an additional day or charge 40 smartphones.
Portable AC Units: A Different Problem
Portable (floor-standing) air conditioners present a harder challenge for battery backup than window units. Every portable AC in our database uses a standard (non-inverter) compressor, and their higher BTU ratings translate to much larger power draws and surge spikes.
Whynter ARC-14S (14,000 BTU): 1,250W running, 3,750W surge.
Midea MAP12S1TBL (12,000 BTU): 1,357W running, 4,071W surge.
These are severe loads. The Whynter surges to 3,750W, which requires a power station with at least 4,688W of surge capacity after applying the 1.25× buffer. The Midea portable AC surges to 4,071W, requiring 5,089W of buffered surge capacity.
Only the largest power stations in our database handle portable ACs reliably:
The Jackery Explorer 2000 Plus (6,000W surge) passes the Whynter with margin. The EcoFlow DELTA Pro 3 (8,000W surge) handles both models with room to spare. The Bluetti AC200L (3,600W surge) fails both.
And even when you can start a portable AC, the runtime is punishing. The Midea portable AC at 1,357W on the EcoFlow DELTA Pro 3 (4,096 Wh): 4,096 × 0.70 / 1,357 = 2.1 hours. The largest battery in our database gives you roughly two hours of portable AC cooling.
Buying Advice
If you are buying an AC specifically for battery backup: Get an inverter model. The Midea MAW08V1QWT and LG LW8022IVSM are both 8,000 BTU inverter window units that typically start on power stations rated 1,000W surge or above. The $100 to $150 premium over a standard AC pays for itself in runtime: 30 to 70 percent more cooling from every charge.
If you already own a standard AC: Check the model number on the unit’s nameplate and look up the surge wattage in our database or the manufacturer’s specifications. For the Frigidaire FHWC084WB1, the surge is 2,010W. If your power station’s peak capacity exceeds that by at least 25 percent (2,513W), you are covered. If not, consider a soft-start device, which limits the initial inrush current by ramping the voltage over 2 to 3 seconds. Our True Surge Protocol applies a 0.45 reduction factor, bringing the Frigidaire’s effective surge down to approximately 905W. At that level, even the Anker SOLIX C1000 (2,400W surge) handles the startup with wide margin. Soft-start adapters cost $50 to $100 and are available as plug-in units for window ACs.
If you need more than 8,000 BTU: Larger inverter window ACs exist (LG makes 10,000, 12,000, 14,000, and 18,000 BTU dual inverter models), but their running watts and surge increase proportionally. At 14,000 BTU, even an inverter model may draw 800W or more running, and runtime on battery becomes the limiting factor rather than surge compatibility.
Ready to check your AC? Look up your model in our compatibility database.
Quick Reference: Inverter vs. Standard on Battery
For a single comparison that captures the entire article:
A Jackery Explorer 1000 v2 ($799, 1,070 Wh, 3,000W surge) paired with a Midea MAW08V1QWT inverter AC ($450) delivers 1.4 hours of cooling at rated load, stretching to 1.9 hours at moderate demand. Total cost: roughly $1,250.
That same Jackery with a Frigidaire FHWC084WB1 standard AC ($300) starts the unit (SAFE verdict, 3,000W > 2,513W buffered surge), but the 670W continuous draw limits you to 1.1 hours per charge with no variable-speed relief.
The inverter path costs $150 more at the AC and delivers 27 to 73 percent more cooling time from any battery. The standard AC starts fine but drains the battery faster and locks you at full draw whenever the compressor cycles on. Both cool the same 350 square feet to the same temperature. The difference is in how far each charge takes you.
The cost of 4 hours of cooling
If your goal is roughly 4 hours of continuous room cooling during a power outage:
| Standard AC path | Inverter AC path | |
|---|---|---|
| AC unit | Frigidaire FHWC084WB1 (~$300) | Midea MAW08V1QWT (~$450) |
| Running draw | 670W (fixed) | ~400W (moderate demand)* |
| Battery needed for 4h | 670 × 4 / 0.70 = 3,829 Wh | 400 × 4 / 0.70 = 2,286 Wh |
| Smallest station that fits | EcoFlow DELTA Pro 3 (4,096 Wh, ~$3,699) | Bluetti AC200L (2,048 Wh, ~$1,499) |
| Total system cost | ~$3,999 | ~$1,949 |
The 400W figure reflects typical inverter operation when the room is near its target temperature. At full rated load (533W), the Midea needs 3,046 Wh for 4 hours, still within range of a $1,899 EcoFlow DELTA 2 Max. The AC200L delivers approximately 3.6 hours at moderate load, not a full 4.
Frequently Asked Questions
Can I add a soft-start device to a standard AC to reduce the surge?
Yes. A soft-start module wires between the power source and the compressor and limits the initial inrush current by ramping the voltage gradually over 2 to 3 seconds. Our True Surge Protocol applies a 0.45 reduction factor for soft-start devices, meaning the Frigidaire FHWC084WB1’s 2,010W surge drops to approximately 905W with a soft-start installed. At that level, even the Anker SOLIX C1000 (2,400W surge) handles the startup with margin. Soft-start devices cost $50 to $100 and are available as plug-in adapters for window AC units. They do not affect the running wattage, only the startup peak.
Are inverter ACs quieter than standard ACs?
Generally, yes. The Midea MAW08V1QWT operates at 52 dB on its lowest fan setting. The LG LW8022IVSM reaches as low as 44 dB in sleep mode. The Frigidaire FHWC084WB1 operates at 55 dB on its lowest setting. The difference is noticeable: 44 dB is the sound level of a quiet library, while 55 dB is comparable to a normal conversation. The variable-speed compressor in inverter models runs at lower speeds during light cooling demand, which reduces mechanical noise. Standard compressors operate at full speed whenever they are on, producing consistent higher noise levels.
How do I find the surge wattage of my AC?
The nameplate on the side or back of the unit lists the rated amperage and voltage, but typically does not list the startup surge directly. For the running watts, multiply the amps by the voltage: the Frigidaire at 5.9A × 115V = 679W (close to the rated 670W). For the surge, you need either the locked-rotor amperage (LRA) from the manufacturer’s engineering data or a measurement with a clamp meter during startup. As a general rule, standard window AC compressors surge at 2.5 to 3.5 times their running wattage. Inverter models typically surge at 1.3 to 1.7 times running wattage. Our device database provides verified surge figures for all AC models we track.
Does an inverter AC work differently during battery-powered operation?
No. An inverter AC runs identically whether powered from the grid or from a portable power station, as long as the power station outputs pure sine wave AC at the correct voltage (115V for residential window units in the U.S.). All portable power stations in our database produce pure sine wave output. The inverter compressor’s variable frequency drive receives standard AC power and handles its own voltage and frequency conversion internally. There is no special setting or adapter needed.
What about 12,000 BTU or larger inverter models?
LG offers dual inverter window units up to 18,000 BTU (the LW1822IVSM). Larger capacity means higher running watts and higher surge, though the inverter advantage still holds proportionally. A 12,000 BTU inverter model typically runs at 700 to 850W with a surge around 1,200 to 1,400W. A 12,000 BTU standard model may run at 1,100W with a surge of 3,300W or more. The relative benefit of the inverter compressor is consistent across BTU ratings: roughly 60 percent lower surge and 20 to 30 percent lower running watts compared to the equivalent standard model.
Sources: Device wattage from OEM manuals and spec sheets in the GeneratorChecker device database. Midea MAW08V1QWT cross-referenced with ENERGY STAR product ID 2620516. LG LW8022IVSM energy savings claim from LG product page. Frigidaire FHWC084WB1 surge derived from NEC hermetic compressor standard (3× running watts). Methodology: How we source and verify device data.