How Much Energy Does A Solar Panel Produce? | EnergySage
How much energy does a solar panel produce?
Higher wattage doesn't always mean better performance.
Solar panel power output can get confusing fast. Is 400 watts good? 420 watts? Should you opt for the 450-watt panel? Is it worth the extra cost?
About 97% of home solar panels quoted in the second half of 2025 produce between 400 and 460 watts, based on thousands of quotes from the EnergySage Marketplace. But wattage alone doesn't tell the whole story. In fact, efficiency matters more than wattage when comparing solar panels—a higher wattage can simply mean that a panel is larger.
The panels you choose help determine how much you'll save on electric bills. Install panels that don't produce enough power, and you'll wait years longer to break even. Choose panels with an output that's too high for your roof space or energy needs, and you'll waste money on capacity you'll never use.
We'll break down everything that influences solar panel output—from efficiency ratings and cell technology to real-world factors like weather and roof angle. That way, you'll know how to evaluate panels based on their actual performance, not just their spec sheets.
Key takeaways
- About 97% of solar panels quoted on the EnergySage Marketplace in the second half of 2025 are 400 to 460 watts—expect to see panel outputs in this range in your quotes.
- Your panels' actual output will depend on your roof's shading, orientation, and hours of sun exposure.
- The efficiency and size of your solar panels drive their power output.
- You'll need between 16 and 23 solar panels to cover your home's electricity usage.
Solar panel system size and electricity offset by state
| State | Average system size | Average cost of a solar system before incentives | Average electricity offset percentage | Average cost per watt ($/W) | Average 25-year savings* |
|---|---|---|---|---|---|
| Alabama | 14.26 kW | $55,285 | 76% | $3.88 | $1,896 |
| Arkansas | 14.54 kW | $34,646 | 84% | $2.38 | $26,054 |
| Arizona | 13.64 kW | $30,079 | 97% | $2.21 | $38,038 |
| California | 8.92 kW | $22,049 | 103% | $2.47 | $130,674 |
| Colorado | 11.46 kW | $30,505 | 94% | $2.66 | $22,403 |
| Connecticut | 11.43 kW | $31,167 | 91% | $2.73 | $86,553 |
| Washington D.C. | 10.91 kW | $32,401 | 83% | $2.97 | $111,814 |
| Delaware | 13.76 kW | $34,917 | 90% | $2.54 | $47,461 |
| Florida | 14.54 kW | $30,950 | 93% | $2.13 | $64,842 |
| Georgia | 12.95 kW | $32,301 | 65% | $2.49 | $20,056 |
| Hawaii | 8.86 kW | $30,036 | 113% | $3.39 | $53,845 |
| Iowa | 13.17 kW | $43,172 | 83% | $3.28 | $12,603 |
| Idaho | 13.23 kW | $40,380 | 94% | $3.05 | $ |
| Illinois | 12.47 kW | $37,694 | 89% | $3.02 | $32,618 |
| Indiana | 11.98 kW | $33,456 | 78% | $2.79 | $13,295 |
| Kansas | 12.37 kW | $32,621 | 81% | $2.64 | $26,139 |
| Kentucky | 14.87 kW | $37,863 | 75% | $2.55 | $20,977 |
| Louisiana | 12.69 kW | $29,809 | 75% | $2.35 | $26,918 |
| Massachusetts | 10.96 kW | $31,931 | 92% | $2.91 | $154,721 |
| Maryland | 14 kW | $36,682 | 83% | $2.62 | $78,369 |
| Maine | 11.56 kW | $33,902 | 75% | $2.93 | $78,287 |
| Michigan | 11.82 kW | $34,448 | 83% | $2.91 | $33,597 |
| Minnesota | 13 kW | $42,054 | 89% | $3.23 | $28,357 |
| Missouri | 13.26 kW | $33,332 | 77% | $2.51 | $19,835 |
| Mississippi | 13.26 kW | $32,848 | 73% | $2.29 | $17,067 |
| Montana | 14.23 kW | $32,848 | 81% | $2.29 | $17,067 |
| North Carolina | 13.98 kW | $32,860 | 85% | $2.35 | $31,411 |
| North Dakota | 18.04 kW | $75,451 | 100% | $4.18 | $ |
| Nebraska | 17.52 kW | $63,342 | 94% | $3.62 | $ |
| New Hampshire | 12.66 kW | $36,546 | 89% | $2.89 | $69,473 |
| New Jersey | 12.75 kW | $34,181 | 81% | $2.68 | $79,323 |
| New Mexico | 10.4 kW | $27,766 | 98% | $2.67 | $43,196 |
| Nevada | 12.24 kW | $29,083 | 98% | $2.38 | $26,052 |
| New York | 12.29 kW | $33,951 | 81% | $2.76 | $50,120 |
| Ohio | 13.27 kW | $35,754 | 88% | $2.69 | $49,556 |
| Oklahoma | 14.38 kW | $37,696 | 72% | $2.62 | $20,597 |
| Oregon | 12.13 kW | $29,951 | 87% | $2.47 | $38,278 |
| Pennsylvania | 12.87 kW | $33,140 | 83% | $2.58 | $74,039 |
| Rhode Island | 11.25 kW | $31,108 | 89% | $2.77 | $38,725 |
| South Carolina | 14.41 kW | $37,566 | 83% | $2.61 | $26,701 |
| South Dakota | 16.85 kW | $59,022 | 102% | $3.50 | $ |
| Tennessee | 13.85 kW | $49,262 | 70% | $3.56 | $ |
| Texas | 12.65 kW | $28,455 | 86% | $2.25 | $36,647 |
| Utah | 12.85 kW | $32,162 | 92% | $2.50 | $6,429 |
| Virginia | 14 kW | $35,252 | 80% | $2.52 | $50,182 |
| Vermont | 11.51 kW | $31,791 | 90% | $2.76 | $37,119 |
| Washington | 13.48 kW | $34,326 | 69% | $2.55 | $36,874 |
| Wisconsin | 13.03 kW | $40,502 | 92% | $3.11 | $45,635 |
| Wyoming | 11.69 kW | $41,379 | 91% | $3.54 | $17,815 |
Note: These costs are based on EnergySage Marketplace data. They were last updated on August 21, 2026.
What is solar panel efficiency?
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 17-23% 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 polycrystalline cells tend to be more affordable—they are no longer typically used in home solar panels.
Researchers are constantly working to improve solar cell technology. In 2025, LONGi achieved a 33% solar cell efficiency record, though these advanced cells are still too expensive to be incorporated into most commercially available solar panels. For now, the most efficient residential solar panels available top out around 23%, but ongoing innovation means efficiency continues to improve.
Higher cell efficiency = higher wattage panels
Some panels' high power output rating is due to their larger physical size rather than high efficiency. If two solar panels have 20% efficiency ratings, but one has a power output rating of 350 watts and the other is rated at 400 watts, all that means is that the 400-watt panel is about 14% larger than the 350-watt panel. You'll get more power out of the 400-watt panel, but only because it takes up more space on your roof.
We generally divide solar panels into two size groups: 60-cell solar panels and 72-cell solar panels.
- 60-cell solar panels are typically used in home installations. They’re around 5.8 feet tall by 3.5 feet wide, on average.
- 72-cell solar panels are generally used in commercial solar projects and have an extra row of cells. They're around 7.5 feet tall by 3.7 feet wide on average.
Low-efficiency cells are fine if your panels are big enough
In the same vein, low-efficiency solar cells can be a great choice if your panels are large enough because the total output power is a combination of efficiency and size.
For example, you can have a high-efficiency 350-watt panel or a larger, low-efficiency 350-watt panel. Both produce 350 watts; the latter just takes up more space on your roof.
Low-efficiency panels are often cheaper per watt, so you can typically save on upfront costs if you have the roof space to accommodate larger panels without sacrificing the overall output of your solar panel system.
More sunlight = more energy
No matter how efficient or how large your solar installation is, it won't produce any energy in the dark. A solar panel's energy production is only as good as its orientation towards and exposure to the sun. You can get more energy out of your solar panels by following these tips:
- Minimize shading. It may seem obvious, but if there's shade blocking the sun, your solar panel output will be low. You may need to cut back some trees to get the most out of your panels.
- Orient your panels for maximum production. In general, south-facing panels at a 30-degree angle will produce the most electricity. But east- and west-facing panels usually produce plenty of energy. The ideal angle for your panels depends on your latitude. Angles between 15-40 degrees are usually fine.
- Maximize your solar panels' hours of sunlight. During the summer, your solar panels will produce more electricity than during the winter and some areas get more hours of sunlight than others. Roofs with a lot of sunlight hours have high production ratios, which means solar panels produce a lot of energy (in kWh) relative to output (in watts). So other than moving (which we don't recommend unless you're already considering it), the best thing you can do is ensure your panels get as much sun exposure as possible during the day by minimizing any obstructions between the sun and your panels.
How much power does a solar panel produce?
About 97% of home solar panels included in EnergySage quotes today have power output ratings between 400 and 460 watts. The most frequently quoted panels are around 430 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 kilowatt (kW) system produces 15,000 kilowatt-hours (kWh) of electricity in a year.
Solar production ratio by state - Infogram
Average solar production ratio by state
Source: EnergySage Marketplace data, 2026
You can calculate your estimated annual solar energy production by multiplying your solar panel's wattage by your production ratio. For example, a 430-watt panel in California will produce about 645 kWh in a year, or about 1.77 kWh daily. That's enough energy to power some small appliances without too much issue.
Quick question
How many kWh will you get out of a full solar panel system?
It's more useful to know how much solar power your whole roof can generate rather than just a single panel.
Take our example above where you live in California. Let's say you get 28 430-watt solar panels installed on your roof: That gives you a 12,040 watt, or 12 kW solar panel system (about the average system size quoted on the EnergySage Marketplace).
When we multiply the system's size (12,040 watts) by your production ratio (remember it's about 1.5 in California), we get 18,060 kWh of annual solar production or 1,505 kWh each month. Considering an average household uses 899 kWh per month, this should be more than enough to cover your electric bills.
What are the highest output solar panels?
We looked through thousands of quotes on the EnergySage Marketplace and found that Maxeon offers the solar panel with the highest output for homes: 440 watts, 22.8% efficiency, and a power density of 21.6 watts per square foot.
Highest output home solar panels on EnergySage in 2026
| Brand | Solar panel model | Wattage | Efficiency | Size | Power density (W/sq.ft) |
|---|---|---|---|---|---|
| Hyperion Solar | _DH108P8-395 | 395 W | 20.2% | 3.88 x 3.56 ft | 28.5 |
| Canadian Solar | TOPHiKu6 | 465 W | 23.3% | 3.72 x 5.78 ft | 21.6 |
| Maxeon | Maxeon 6 | 440 W | 22.8% | 3.43 x 5.94 ft | 21.6 |
| CW Energy | CWT 450W | 450 W | 23.0% | 3.72 x 5.65 ft | 21.4 |
| ReneSola | RS41-450NX-E3 | 450 W | 23.0% | 3.72 x 5.65 ft | 21.4 |
| Sirius PV | ELNSM54M-HC-N 450 | 450 W | 23.0% | 3.72 x 5.65 ft | 21.4 |
| CertainTeed | CTTC450HC12-08 | 450 W | 23.0% | 3.72 x 5.66 ft | 21.4 |
*This table only includes residential solar panel models from brands quoted at least 100 times in the EnergySage Marketplace.
quick calculation
How to calculate your solar panel wattage
You can calculate a panel's wattage by multiplying its volts x amps. Volts represent the amount of force of the electricity, while amperes (amps) refer to the total amount of energy used. But honestly, don't worry too much about this because the wattage of your panel should be very clear in any solar quotes you get.
Can you save more money with a bigger solar panel system?
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, but it’s worth it if you need that extra energy to fully cover your electric bills.
Let's assume you spend $175 each month on electricity and need a 10 kW system to fully cover your usage. A 10 kW solar installation costs $2.58/W on average, for a total of $25,800 before any available incentives. A smaller 7 kW system is about $2.62/W, costing $18,340.
Without solar, you'd spend $78,297 on electricity over 25 years, assuming an annual inflation rate of 3.2%. With the 10 kW system, your electricity is essentially free, so your only expense is the system cost of $25,800, excluding any electricity you may need to draw from the grid when your panels aren’t producing. With the 7 kW system, only about 70% of your electric bill is offset, so you still end up paying $23,489 on electricity over 25 years. The 7 kW system may be cheaper upfront, but you will lose $16,029 in overall savings.
| No solar | 7 kW system | 10 kW system | |
|---|---|---|---|
| Cost per watt ($/W) | $0 | $2.62 | $2.58 |
| Cost of system (assuming no incentives) | $0 | $18,340 | $25,800 |
| Cost of electricity over 25 years | $78,297 | $23,489 | $0 |
| Total cost | $78,297 | $41,829 | $25,800 |
Bigger solar panels aren’t necessarily better
When it comes to solar panel size, bigger isn't always better. The highest output panels in our list all share one thing in common: exceptional efficiency. They convert over 22% of the sun's energy into electricity, which is why they generate so much power.
But efficiency matters even more when you're working with limited roof space. The average household needs between 16 and 23 solar panels to get rid of its electric bills. A compact, high-efficiency panel can produce just as much electricity as a larger panel with lower efficiency—meaning you can generate the power you need without covering every inch of your roof.
Solar panel wattage isn't just a spec sheet number—it's the foundation of your entire solar investment. Choose panels with output that matches your electricity needs and roof constraints, and you'll watch your utility bills shrink month after month. Miss that mark, and you'll either overpay for capacity you'll never use, or you'll undershoot your energy goals.