Solar System Performance

In order to understand how much power your solar panels can produce and how this might vary over time, we need to look at solar system performance and efficiency. 

Tron Solar is a company that specializes in solar energy systems, and in this article, we will discuss solar system performance from their perspective. To begin with, solar system performance is the amount of energy produced by solar panels at any given moment or over a specified period, measured in watts. The size and conditions of the solar energy system determine its performance. Solar panel efficiency, on the other hand, is a percentage that measures how well solar panels convert sunlight into usable electricity. Both performance and efficiency are dynamic, meaning they can change over time and need to be monitored regularly.

Designing for Solar Performance

When designing a solar energy system, many variables can affect its performance, and these should be addressed in the design process. Matching the system to the household’s energy needs requires a thorough understanding of site conditions that impact system performance. Factors that affect performance include system size, solar energy offset, peak sun hours, roof pitch, orientation, shading, and irradiation.

System Size

System size is calculated by multiplying the number of panels by their power rating. For example, a 10-panel system that uses 400 watt panels will have a system size of 4,000 watts or 4 kilowatts (kW). A larger system will produce more power, assuming standard test conditions.


Solar energy offset measures the amount of electricity generated by solar panels compared to the electricity consumed in the home, expressed as an annual percentage. The offset requires a careful audit of historical energy usage to target a specific offset and determine the right system size. Changes in energy consumption, such as new appliances, electric vehicles, additional residents, or working from home, also need to be considered.

Peak Sun Hours

Peak sun hours reflect the average daily amount of time that the sun’s rays are most powerful, calculated as an annual average to account for seasonal changes in sunlight and intensity. Areas with low peak sun hours might need a larger system to achieve the same results.

Roof Pitch and Orientation

Roof pitch, orientation, and complexity play a significant role in the design and performance of a solar energy system. Solar panels perform best in direct sunlight, hitting the panels at a 90° angle or as close to perpendicular as possible. South-facing roof surfaces generally perform best in the U.S., and the pitch or angle of the roof should match the longitudinal coordinates of the home.

  • A homeowner in Miami, Florida, 25.7° north of the equator, will yield the best solar system performance by mounting panels on a south-facing roof surface with a 25° pitch. 
  • A homeowner in Portland, Oregon, 45.5° north of the equator, would benefit from a roof pitch closer to 45°.


Shading reduces the amount of energy produced by solar panels. Nearby structures or buildings may be difficult to address, but shading from nearby trees can be mitigated by trimming or removing select trees.


Tron Solar uses proprietary 3D LiDAR data and mapping software to calculate the solar irradiation for every square meter of a roof across every hour of the year. Irradiation is the sum of solar energy falling on a surface over a given period of time. This data accounts for the effects of shading, roof pitch, orientation, and other factors on solar energy system performance. By addressing these factors in the design process, Tron Solar can optimize solar system performance and improve the long-term savings potential and health of solar energy systems.

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