How Many Solar Panels Do You Need to Run an AC Unit?

1. Understanding AC Power Consumption

AC units come in various sizes and cooling capacities, typically measured in tons or BTUs (British Thermal Units). Their power consumption varies widely:

Small Window AC (5,000–10,000 BTU): 500–1,200 watts

1-Ton Split AC (12,000 BTU): 1,000–1,500 watts

1.5-Ton Split AC (18,000 BTU): 1,500–2,000 watts

2-Ton Central AC (24,000 BTU+): 2,000–3,500+ watts

The running wattage also differs from the startup wattage. AC compressors often need 2–3 times more power to start, so your solar inverter and system must handle these surges.

2. Solar Panel Output Basics

A standard residential solar panel typically generates between 300–400 watts per panel under peak sunlight conditions (about 4–6 hours per day, depending on your location).

For calculation purposes:

1 solar panel = 350 watts × 5 sunlight hours ≈ 1.75 kWh/day

3. Calculating Solar Panels for an AC Unit

Let’s walk through an example.

Example: Running a 1.5-Ton Split AC (1,500 watts)

Daily usage: 8 hours

Power consumption: 1,500 × 8 = 12,000 Wh (12 kWh/day)

Now, divide by daily panel production:

12 kWh ÷ 1.75 kWh/panel ≈ 7 panels (350W each)

So, you would need at least 7 high-efficiency solar panels to run a 1.5-ton AC for 8 hours daily, assuming ideal sunlight.

4. Factors That Influence the Number of Panels

Geographical Location: Areas with more sun hours (Arizona, California, India, etc.) require fewer panels compared to cloudy regions.

AC Efficiency (EER/SEER Rating): Energy-efficient units consume less power.

Battery Storage: Off-grid systems need batteries to store excess energy for nighttime cooling.

Grid-Tied vs. Off-Grid: In grid-tied setups, you can draw power from the grid when solar isn’t sufficient.

5. Practical Setup Scenarios

Running a Small Window AC (500W): Needs 2–3 panels for 6–8 hours daily use.

Running a 1-Ton Split AC (1,200W): Around 5 solar panels for daily operation.

Running a 2-Ton Central AC (3,000W+): Could require 12–15 solar panels, depending on hours of use.

6. Key Takeaways

The number of solar panels depends on AC size, daily usage, and sun availability.

A 1.5-ton AC typically requires 6–8 solar panels (350W each) for daily operation.

Adding battery storage is crucial for off-grid setups to run the AC at night.

Choosing a high SEER-rated AC unit reduces the number of panels needed.