Solar · Cooling & fans

How many solar panels to run a window AC?

A typical window AC uses about 5.67 kWh a day in the months you use it (about 120 days a year), based on the median ENERGY STAR model (709 W) for 8 hours a day, 120 days a year (681 kWh/yr). Off-grid with a battery, that takes about 2,760 W of solar panels (14 × 200 W) to keep up in December, the worst month in Tennessee (the middle state for sunshine), or 1,950 W in an average month, plus a battery of about 6,680 Wh. On a grid-tied home system it adds about 681 kWh a year: 0.46 kW, or 2 × 400 W panels.

Energy use5.67 kWh/dayper day of use
Off-grid panels2,760 Wworst month, Tennessee
Battery, 1 day6,680 Whpower station or lithium
Grid-tied2 × 400 W681 kWh/yr

Appliance energy: our window AC page (sources there) · solar: Global Solar Atlas 2.0 · solar data reviewed 2026-11-05

Can a panel and battery keep it running where you are?

Your situation: keeping a window AC running on solar. Different situation?

1

Your battery and panel

Battery size in

On the box: a station’s Wh is its battery; a panel’s W is its rated output. A 12 V 100 Ah battery is 1,200 Wh.

2

Where and how

Its motor needs about 900–2,400 W for a moment at start-up, so the inverter or power station must handle that surge; the panels don’t. Watts and hours for a different model or use: change them on the off-grid sizer, which adds up several appliances.

By state

Off-grid columns size the panels for the month named (with 85% charging and 85% inverter losses). The grid-tied column covers its yearly use on a home system.

Panels to run a window AC in every state
StateOff-grid, worst monthOff-grid, average monthGrid-tied, 400 W panels
Alabama2,490 W1,880 W2
Alaska12,050 W2,660 W2
Arizona1,790 W1,510 W1
Arkansas2,480 W1,890 W2
California2,080 W1,600 W1
Colorado1,960 W1,640 W1
Connecticut2,780 W1,960 W2
Delaware2,680 W1,960 W2
District of Columbia2,560 W1,950 W2
Florida2,100 W1,780 W2
Georgia2,390 W1,860 W2
Hawaii2,080 W1,710 W2
Idaho3,560 W1,790 W2
Illinois3,320 W2,010 W2
Indiana3,460 W2,040 W2
Iowa3,130 W1,980 W2
Kansas2,370 W1,830 W2
Kentucky3,160 W2,010 W2
Louisiana2,390 W1,850 W2
Maine3,100 W2,020 W2
Maryland2,660 W1,970 W2
Massachusetts2,910 W2,000 W2
Michigan4,340 W2,130 W2
Minnesota3,430 W2,030 W2
Mississippi2,460 W1,860 W2
Missouri2,630 W1,910 W2
Montana3,510 W1,950 W2
Nebraska2,680 W1,900 W2
Nevada1,870 W1,500 W1
New Hampshire2,930 W2,010 W2
New Jersey2,790 W2,000 W2
New Mexico1,740 W1,490 W1
New York2,740 W1,960 W2
North Carolina2,340 W1,860 W2
North Dakota3,560 W1,970 W2
Ohio3,850 W2,120 W2
Oklahoma2,230 W1,790 W2
Oregon4,800 W2,200 W2
Pennsylvania2,900 W2,020 W2
Rhode Island2,740 W1,980 W2
South Carolina2,270 W1,830 W2
South Dakota2,840 W1,900 W2
Tennessee2,760 W1,950 W2
Texas2,400 W1,890 W2
Utah2,930 W1,760 W2
Vermont4,410 W2,200 W2
Virginia2,380 W1,890 W2
Washington5,480 W2,220 W2
West Virginia3,500 W2,130 W2
Wisconsin3,500 W2,030 W2
Wyoming2,350 W1,730 W2

FAQ

How many solar panels to run a window AC?

A typical window AC uses about 5.67 kWh a day in the months you use it (about 120 days a year), based on the median ENERGY STAR model (709 W) for 8 hours a day, 120 days a year (681 kWh/yr). Off-grid with a battery, that takes about 2,760 W of solar panels (14 × 200 W) to keep up in December, the worst month in Tennessee (the middle state for sunshine), or 1,950 W in an average month, plus a battery of about 6,680 Wh. On a grid-tied home system it adds about 681 kWh a year: 0.46 kW, or 2 × 400 W panels.

Can a 200 W solar panel run a window AC?

Not on its own in Tennessee: even in the best month a 200 W panel puts back less than a typical window AC uses (5.67 kWh a day). It takes about 2,760 W to keep up all year, at 85% charging and 85% inverter efficiency. A panel alone can’t run it at night or under cloud; the battery does that.

What size battery do I need for a window AC on solar?

About 6,680 Wh to cover one day without sun (a day’s use ÷ 0.85 inverter efficiency, for a power station or lithium battery). Double it for lead-acid, which shouldn’t be run below half.

How many kWh does a window AC use a day?

About 5.67 kWh a day in the months you use it (about 120 days a year), based on the median ENERGY STAR model (709 W) for 8 hours a day, 120 days a year (681 kWh/yr). Your own use depends on the model and how you use it.

Sources and assumptions

Note: These are estimates; shading, roof direction, local weather, equipment and your installer’s design change the real output. We give no wiring or installation advice: follow your equipment’s manuals, and use a licensed installer for any system connected to your home’s wiring or the grid. Net metering and export credits are not modelled. Not financial or tax advice.

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