How Many Solar Panels Do I Need for My House?

The average American home needs between 17 and 24 solar panels. But your home is not average.

The number of panels you need depends on four things: your energy usage, your roof size, your location, and your roof orientation.

Here is how to figure it out yourself.

Step 1: Check Your Electric Bill

Look at your monthly electric bill. Find the kilowatt-hour (kWh) usage. This is usually listed near the top of the bill.

The average US home uses about 10,649 kWh per year. That is about 887 kWh per month.

If your usage is higher, you need more panels. If it is lower, you need fewer.

Step 2: Know Your Location

Solar panels produce more energy in sunny locations. A panel in Phoenix produces about 5.5 peak sun hours per day. A panel in Seattle produces about 3.5.

That means a Phoenix home needs roughly 30% fewer panels than a Seattle home for the same energy production.

Step 3: Check Your Roof Size

Each solar panel takes up about 17 to 18 square feet. A 20-panel system needs roughly 340 to 360 square feet of unshaded roof space.

If your roof is smaller, you may need higher-efficiency panels that produce more power in less space. These cost more but fit on smaller roofs.

Step 4: Consider Your Roof Orientation

South-facing roofs produce the most energy. East and west facing roofs produce about 80% to 90% as much. North-facing roofs produce 20% to 40% less.

If your roof faces north, you will need more panels to make up for reduced production.

The Quick Calculation

Here is a rough estimate:

• High usage (1,500+ kWh/month): 25 to 35 panels
• Average usage (800-1,500 kWh/month): 17 to 25 panels
• Low usage (under 800 kWh/month): 10 to 17 panels

This is a rough estimate. The actual number depends on your specific roof, location, and panel efficiency.

Get an Accurate Count

Instead of guessing, run a satellite analysis. SolrScan checks your roof and tells you exactly how many panels will fit and how much energy they will produce.

It costs $19 and takes 60 seconds. No sales call. No waiting.

solrscan.com

Know your panel count before you sign a contract.