Understanding Your Solar System's Output

By Melanie Dawn

May 22, 2025

So you've finally decided to go solar, but you're still new to the idea. Those shiny panels on your roof do more than just add to the aesthetic. They determine how much energy your system produces.

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How Do I Calculate My Solar System's Output?

To calculate solar output, you’ll need several pieces of information.

System size. This information is provided in kilowatts. Check for a single-line diagram near your electric panel. If you can’t find the diagram, you can also calculate the total by multiplying the wattage of each panel by the number of panels you have.
Average peak hours of the sun. Most areas in the United States receive 3 to 5 peak hours of sunlight a day. You can determine how much your area gets by checking a peak sun-hours map.
Account for losses. Solar panel systems aren’t 100% effective. Things like shade and system age can reduce how well your system works by as much as 20%. To account for the losses, you’ll need to multiply your system’s output by 0.8.

Once you’ve gathered the information, multiply your system size in kW by the number of peak sun hours. Finally, adjust for losses.

What Affects the Output of a Solar Panel System?

Factors affecting production capacity include:

Amount of sunlight. One of the biggest things that can affect your solar system output is the amount of sun your panels get daily. Some regions receive more sunlight and will naturally produce more energy.
Panel setup. Professional installation of your panels is recommended to ensure installation at an optimal angle. Panels should also be secure to minimize losses.
Shade. Cloud cover can reduce the amount of sunlight reaching the panels on a given day. Trees, buildings and other structures can also reduce the sunlight your panels receive.
Temperature. Contrary to what you might think, excessively hot temperatures can reduce the output of your solar panels. High heat decreases the voltage output and reduces system performance.
System age. Solar panels decrease in efficiency each year. A newer system produces more energy than an older one.
Cleanliness. Dirty solar panels prevent sunlight from penetrating. Clean panels equal more power generation.

How Do I Monitor My System's Solar Energy Production?

Most solar panel systems feature a display or monitoring system, allowing you to track how much energy your system produces. Check the log on your inverter display for daily and historical output information. If you have an app, you can view real-time and historical data from your phone or smart device. Most system apps offer daily, weekly and monthly energy production and system trends. You may also receive alerts when your panels are performing at their peak.

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How Do I Optimize My Solar Power Output?

Optimizing your solar energy output ensures your solar panels produce as much energy as possible. The following strategies can help enhance your solar panel’s performance.

Reduce shade. Keep the area around your solar panels clean and tidy by cutting back trees and foliage. During installation, place your panels in a location that won’t be affected by buildings and other structures at any time during the day.
Adjust the position. Solar panels should face true south to receive maximum sunlight. You can also adjust the tilt on your panels to account for time of year and time of day.
Perform regular maintenance. Clean your solar panels at least twice a year to remove dust, debris and dirt accumulation. It’s also a good idea to schedule an appointment with a professional once a year to check for loose connections and potential malfunctions.
Install power optimizers or micro-inverters. Power optimizers and micro-inverters are installed directly on each solar panel to help maximize performance. Both can enhance how well your panels work and increase output.
Add a battery-storage system. During peak times, store surplus energy in a battery-storage system. This gives you additional power reserves when energy production drops on cloudy days or at night.

What Is a Good Level of Solar Energy Output?

Ideally, your solar panel system should produce at least as much energy as your home needs. Determining what’s good for your system depends on the system’s size, location and installation specifics. Use the formula above to determine panel output. For example, a 100-watt panel exposed to 5 hours of sunlight a day should have a solar system output of 500 watts of power.

Check your inverter display or app for actual energy production. A well-functioning system should have a performance ratio of around 75%, so the above panel should produce 375kW of power. If solar power production falls below this level, it may be time to schedule an appointment with a professional for maintenance and repairs.

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