How many solar panels do I need to power my home?

When people first consider the idea of going solar, one of the very first questions that comes to mind is “how many solar panels do I need to power my home?”

Though the only accurate and reliable way to size a solar system is based on your personal energy usage, we understand not everyone has that information readily accessible. For those of you just beginning your solar research, we wanted to provide benchmark system sizes based on familiar reference points, like square footage and number of bedrooms in your home, to give you a starting point for your research.

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Before we go further, we should be clear: these tables are estimates projected based on US national averages. Your energy needs may differ from what is typical of the average American home.

These tables give a benchmark to help you answer preliminary questions like how many panels can fit on your roof and whether going solar fits within your budget. If you decide to move forward, you will need to gather energy usage data and size a system around your individual needs.

Jump to the data:

How many solar panels do I need…

• Based on the square footage of my home?
• Based on the number of bedrooms in my home?
• Based on my monthly electric bill?
• Based on my household energy usage? (Most accurate estimate)

Methodology

We referenced US Census data on average household energy usage, cost of electricity, and occupancy per square foot in the US to work out these projections. In all cases, the tables shown reflects how many solar panels you would need to fully power an “average” American home based on the data available to us.

Because panels come in a wide range of wattages, we’ve run the numbers for two different panel sizes: 315W and 375W. If you opt for lower-efficiency panels, you’ll need more panels in your array to hit the target production number.

Keep this in mind if space is a concern. With limited roof space, you may need to invest in more efficient panels to be able to fit the array on your roof. We’ve provided a range in our projections (from 315W to 375W) to give you a sense of how much it impacts the physical layout of the array.

How many solar panels do I need based on the square footage of my house?

Know the square footage of your home? This table cross-references on US Census data on the average household square footage against the average monthly electric usage of an American household to estimate how many panels you may need based on the size of your home.

How many solar panels do I need based on the number of bedrooms in my home?

If you don’t know the square footage of your house off the top of your head, we’ve also estimated average system size based on the number of bedrooms in your home. 

These estimates are based on research from the NAHB (National Association of Homebuilders) which reports the average American home has 3.38 bedrooms. We’ve referenced that figure against the average monthly electric usage of an American household to produce the table below.

How many solar panels do I need to eliminate my electric bill?

Lastly, let’s assume you pay the national average rate for electricity, which is 13.3 cents/kWh.  Here’s how many solar panels you would need based on your average monthly electric bill.

How many solar panels do you need based on your kWh usage?

The tables above simply give a starting point to get you in the ballpark. If you decide to move forward with your project, you’ll need to go through a more accurate sizing process based on your personal energy usage.

Energy usage is measured in kilowatt-hours (kWh), which can be found on your monthly electric bill. 

Ideally, you want to base your system design off the past 12 months of electric bills, to account for peaks and valleys in usage. Bills tend to be higher during summer and winter due to the need to run A/C and heat.

The table below shows benchmark system sizes based on your average monthly energy usage. This is the most accurate way to size out your system, so if you have your energy usage data available, we’d recommend starting here.

To hone in on a more accurate figure, head over to our solar cost calculator and enter your ZIP code and energy usage data. We’ll provide an accurate cost and system size estimate that takes your usage and local climate into account.