How much energy does a solar panel produce?

Most home solar panels that installers offer in 2024 produce between 350 and 450 watts of power, based on thousands of quotes from the EnergySage Marketplace. Each of these panels can produce enough power to run appliances like your TV, microwave, and lights. To power an entire home, most solar panel owners need 17 to 30 solar panels. 

The amount of electricity your solar panels produce directly impacts your long-term savings. If it doesn't cover your electric bill, it will take a lot longer to break even on your solar installation. A solar panel's output rating, or wattage, is the best indicator of its power production. Especially if you have a small roof, it's important to choose a solar panel model that will generate enough power to offset the amount of electricity you use. 

We'll help you understand why your roof's square footage, shading, orientation, and sun exposure are important to choosing the right solar panel. You don't want to waste money on high-wattage panels if you don't need them.

Solar panel system size and electricity offset by state

Of all the metrics to look at when you're shopping for solar panels, cell efficiency is one of the most important. The higher a panel's efficiency, the more power it can produce. Most solar panels have cells that can convert 17-22% of the sunlight that hits them into usable solar energy. The efficiency depends on the type of cell in the panel. Monocrystalline cells are more efficient and generate more electricity, while solar panels with polycrystalline cells tend to be more affordable. 

In 2022, the National Renewable Energy Laboratory (NREL) developed the most efficient solar cell to date at 39.5% efficiency, though it's too expensive to be incorporated into solar panels you can buy today. NREL's team of researchers is working to improve solar cell technology, so we may see higher efficiency panels in the future.

Most home solar panels included in EnergySage quotes today have power output ratings between 350 and 450 watts. The most frequently quoted panels are around 400 watts, so we'll use this as an example. If you live in a sunny state like California, your panel's production ratio is probably around 1.5, meaning a 10 kW system produces 15,000 kWh of electricity in a year.

You can calculate your estimated annual solar energy production by multiplying your solar panel's wattage by your production ratio. This means a 400-watt panel in California will produce about 600 kWh in a year, or about 1.6 kWh daily. That's enough energy to power some small appliances without too much issue.

We looked through thousands of quotes on the EnergySage Marketplace and found that LA Solar Factory offers the solar panel with the highest output for homes: 550 watts and 21.28% efficiency. 

Highest output home solar panels quoted on EnergySage in 2024

*This table only includes solar panel models with over 20% efficiency that appeared in at least three Marketplace quotes. 

Because solar panel companies usually offer more than one line of solar panels, the power output of their products ranges widely. When we look purely at power output, here's what you can expect from the frequently quoted solar panel brands on EnergySage: 

Solar panel wattages from popular brands

We often compare solar quotes based on dollars per watt ($/W) to make it easy to evaluate them based on price and power output. A system with higher wattage panels usually costs more than one with lower wattage panels. If you need that extra energy to fully cover your electric bills, it's worth it. You'll pay more upfront, but your savings on electric bills usually make up the difference. 

Let's assume you spend $150 each month on electricity and need a 10 kW system to fully cover your usage. A 10 kW solar installation costs $2.73/W on average, for a total of $19,110 after the federal tax credit. A smaller 7 kW system is about $2.81/W, costing $13,769 after the tax credit.

Without solar, you'd spend $63,930 on electricity over 25 years, assuming an annual inflation rate of 2.8%. With the 10 kW system, that electricity is free, so your only expense is the system cost at $20,580. The 7 kW system only offsets about 70% of your electricity bill, so you still end up paying $19,179 on electricity over 25 years. The 7 kW system may be cheaper upfront, but you lose out on $13,838 in savings overall.