Can solar panels power a whole house?

Since solar panels don’t generate electricity when the sun is down, many homeowners wonder if photovoltaic solar arrays can generate all the electricity they need for their homes.

Fortunately, with enough panels, a solar system can completely cover your home’s energy usage. This is usually made possible by a net metering program from a local utility company. These programs enable your solar panels to eliminate your electricity costs, even when the sun isn’t out. If your area doesn’t have net metering or you don’t want to rely on the power grid at all, though, you can add battery storage to your solar system instead.

Keep reading and we’ll help you determine how many solar panels you need, teach you about net metering programs, examine the benefits of solar batteries, and break down the advantages and costs of switching to solar.

How many solar panels do you need to power your whole home?

The perfect number of solar panels for your home will depend on how much energy your household actually uses, the power rating for each panel you install, and how efficiently the panels can run in your area.

This step-by-step guide can help you determine how many solar panels you need to power your entire home.

Step 1: Check your electricity usage
First, look over your power bills to learn how much electricity your home consumes on average every month. Power usage fluctuates with the seasons, so look at your monthly bills from one entire year, add the number of kilowatt-hours you used each month together, and divide the total by 12 to get a holistic average.

Step 2: Find out how many peak sun hours your area gets
Because the actual output of a solar panel is partially determined by how much direct sunlight it receives every day, the next step is finding out how many peak sun hours your area sees every day.

We can help you with this part. We’ve listed the number of peak sun hours each state receives on average, so you can quickly discover how many you can rely on by checking our list.

Step 3: Determine solar panel wattage
Next, check the wattage of any solar panels you might purchase to determine the amount of electricity they can output. Not all panels produce the same amounts of energy, and their output is represented by their wattage. The lower the power rating of your panels, the more of them you’ll need to power your home.

When talking about the energy output of an entire solar panel system, you combine the wattage of all its panels, and this means talking in terms of thousands of watts. For simplicity, you can shorten the numbers by measuring the output in kilowatts (kW) instead of watts. 1,000 watts is equal to one kilowatt, so 16 solar panels that each have a rating of 300 watts have a collective rating of 4.8 kW.

Under perfect conditions, a 4.8 kW solar power system can create 4.8 kWh of energy in a single hour. In the real world, the system will produce less energy than this.

Step 4: Calculate how many solar panels you need
Now it’s time to do some math.

First, let’s say your household consumes the U.S. average of 893 kWh every month. Then, let’s say your home’s in Florida, a state that gets 4 peak sun hours daily. Multiply this number by 30 to determine how many peak sun hours your home sees every month: 120. So, a 1 kW solar system on your roof would produce roughly 120 kWh of electricity every month.

Next, divide your home’s energy consumption by 120 kWh to determine how many kW of solar panels you should install to get all the electricity your home needs. 893 kWh divided by 120 kWh is 7.44 kW, so you’d need a 7.5 kW system to cover your energy consumption.

For the final step, let’s say the solar panels you’re likely to purchase are rated for 400 watts. Divide 7,500 by 400 to determine how many of those panels your system will require. The answer is 18.75, so we’ll round up and say that you’d need 19 of those solar panels for your home.

You can now use this same formula to determine how many solar panels you’d need to cover your entire home’s energy consumption.