How Many Solar Panels are Needed to Power a House?

The number of solar panels needed to power a house is based on many factors. On average, it takes between 20 and 40 solar panels to power a typical home in the United States, depending on your house’s size and energy usage, the climate you live in, and the type of solar panel system you install.

This article discusses roughly calculating the number of solar panels needed to power your house.

1. Calculate the average energy usage for your house

Calculate the Average Energy Usage for Your House
Calculate the Average Energy Usage for Your House by Clay’s Climate Control

According to the U.S. Energy Information Administration (EIA), the average U.S. household uses about 893 kWh of electricity per month or 30 kWh per day.

However, your electricity usage will be different based on the size of your house, the number of people living in your home, and how energy-efficient your house is.

The best way to calculate your specific electricity usage is to look at your past utility bills. Assuming you have your past utility bills handy, calculate your household’s average kWh per month and day.

If you don’t have your past utility bills, you can still estimate your electricity usage by using this electricity usage calculator.

In our example, we’ll assume that your home uses about 30 kWh of electricity per day, so we are looking for a solar system that can generate this amount of power.

2. Determine how much sunlight reaches your house

Peak sun hours map
Peak sun hours map by Solar Craft

If you live in an area with a lot of direct sunlight, you won’t need as many solar panels to produce the same amount of electricity as someone who lives in an area with less sunlight.

The easiest way to determine how much sunlight hits your house is to look at the number of sun hours in your area.

On average, most of the United States gets about 3-5 sun hours per day. In our example, we’ll assume that your house gets five sun hours per day.

3. Calculate the required size of your solar system

Calculate the Required Solar System Size
Calculate the Required Solar System Size by EGIM

There are a few ways to calculate the size of the solar system you need. The most common way is to divide the amount of energy your home uses by the number of sun hours it gets. We can use this basic equation for this:

Solar System Size (kW) = Energy Usage (kWh) / Sun Hours (h)

We are looking for a solar system that can generate 30 kWh of electricity per day in our example. Since our house gets five sun hours per day, we need a solar system that can generate (30 / 5) at least 6 kilowatts (kW) of electricity.

Home square footage compared to the number of solar panels needed in 2022 by energysage

4. Consider the solar panel wattage

Consider the Solar Panel Wattage
Consider the Solar Panel Wattage by Enterprise Press

When shopping for solar panels, you’ll see that each panel has a wattage rating. This is the amount of electricity the panel can produce in an hour.

For example, a 200-watt solar panel can produce 200 watts of electricity for every hour it’s in the sun.

This means that the higher the panel’s wattage, the more electricity it can produce in a given amount of time.

This would also mean that you would need fewer solar panels to produce the same amount of electricity as a lower wattage panel, which is more space-efficient and more expensive.

5. Calculate the number of solar panels you need

To calculate how many solar panels you need, use this equation:

Number of Solar Panels = Solar System Size (Watt) / Solar Panel Wattage (Watt)

In our example, we need a 6kW solar system.

If we choose 200-watt panels, we would need 30 solar panels to reach that goal (6000/200).

But if we select 400-watt panels, we would only need 15 solar panels (6000/40).

Here are some examples of the number of panels needed corresponding to the amount of energy required per year:

Number of solar panels needed for specific system sizes in 2022 by energysage

How much will a solar panel system cost?

Solar Panel Cost per square footage
Solar Panel Cost per square footage by Propeller Madrid

According to the Solar Energy Industries Association (SEIA), the average cost of a residential solar system is $2.94 per watt.

So if you need a 6kW solar panel system, the average cost would be $17,640.

Ultimately, the price of a solar panel depends on the size of the system, the type of panels you choose, where you live, whether you install the system yourself or have it installed by a professional, and many other factors.

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