It's probably the most common question homeowners and solar project developers ask before they go solar. There is no direct answer to this question. Beacuse the number of panels isn't fixed. It's all based on your annual electricity consumption, location (peak sun hours), panel wattage, and budget.

If you need an instant response, feel free to message us. We will promptly provide you with a calculation report based on your requirements. If you prefer to calculate it yourself, follow the steps below to arrive at the desired result.

Step 1: Calculate Your Daily Energy Consumption

Start by gathering your past 12 months' bills of utilities. Look at the total amount of kWh used:

Yearly usage → total of 12 months kWh

Monthly average → divide by 12

Daily average → divide by 30 monthly usage

Example: If your home uses 12,000 kWh per year, that's about 1,000 kWh per month, or 33 kWh per day.

Step 2: Know Your Sun Hours

Not all suns are the same. The U.S. Southwest gets 6+ peak sun hours per day, whereas Northern Europe gets closer to 3. Peak sun hours = avg. # hours in a day with solar irradiance strong enough to deliver full panel output.

A brief guide:

California / Florida → 5–6 hours

Texas → 4.5–5 hours

Seattle / Northern Europe → 3–4 hours

Step 3: Choose Your Solar Panel Wattage

Most home panels today are 300–400 watts (0.3–0.4 kW). High-efficiency panels may be more but cost more.

300W panel = produces ~1.2 kWh/day (with 4 peak sun hours)

400W panel = produces ~1.6 kWh/day (assuming the same)

Step 4: Do the Math

Here's the math in plain English:

Number of Panels = (Annual Energy Usage ÷ Production Ratio) ÷ Panel Wattage

Production ratio accounts for sun hours + system efficiency losses (usually 1.2–1.6).

Example Calculation:

Annual usage: 12,000 kWh

Production ratio: 1.4

Panel wattage: 400W (0.4 kW)

12,000 ÷ 1.4 ÷ 0.4 = 21 panels

So, a typical U.S. home might need between 15–25 panels, depending on location and lifestyle.

Counting 15, 20, or 25 panels is fine for a single-family home. But what if you’re building a solar-powered farm, mining site, or remote industrial project?

Outside of Houses: Thinking in Containers Instead of Panels

For businesses or larger-sized projects, there's an even simpler method to consider: instead of tracking panels individually, you can think about how many 20ft or 40ft LZY foldable PV mobile containers you'd need. Each one holds a pre-assembled solar system, minimizing guesswork and deployment time.

That's when you have to forget panels and start thinking containers.

20ft LZY Mobile Foldable PV Container → deploys ~100 kW+ system

40ft LZY Mobile Foldable PV Container → doubles capacity with scalable design

So instead of "I need 400 panels," you could simply say:
"I need two 40ft containers on site."

Much easier, right?

Other Factors That Change the Number

  • Roof space & structure: Can your roof hold 20 panels? Each is about 40 pounds.
  • Future energy needs: Considering buying an EV? Factor in extra capacity.
  • Solar batteries: With storage (like LZY's LiFePO4 cabinets), you can optimize panel number and reduce grid dependency.
  • Budget & incentives: U.S. federal solar tax credit (30%) and local incentives make a big difference.

Need a Customized Calculation?

If all that math is too much, don't worry. Just provide us with your project location, energy needs, and budget, and our team at LZY Energy will do the math for you. We'll send over a detailed calculation and report to you—and whether a 20ft or 40ft foldable solar container is the right solution.