Solar Panel System Design Process

One of the first steps on the path towards a home solar system is the design. Solar contractors evaluate tons of different factors and data points when calculating the best system for your home, but many people want to get a deeper understanding of exactly how the design process works. In this article, we’ll show you exactly how solar power experts design solar power systems for homes and business owners. 

Let’s start with what solar power experts consider before designing a solar power system for home or business. Several factors are considered during the design process, but two factors are the most important. The first is the amount of roof space available for the installation of solar panels, and the second is the amount of electricity your home consumes each year. Other factors that will affect the design are the specific inverters and panels being used, the roof structure and orientation, and the shading profile.

Many homeowners install their solar panels on rooftops. If you’re considering doing the same, the amount of usable roof space you have will ultimately determine the maximum number of solar panels it can take. While the sizes of each solar panel varies, most of them are 16 square feet in a rectangular shape. The solar panels are attached to fixed racking systems that sit on your roof, so designs that allow panels to be set in rows on the racking are usually the most cost efficient. Few installers will recommend a design that includes panels in small groups of two or three.

Your rooftop space may be limited by several other things competing for space. Things like dormers, chimneys, vents, roof mounted equipment etc. may take up space making it impossible for your solar panels to have enough space to offset 100% of your annual electricity usage. Your contractor will be able to help identify which obstacles are insurmountable and which can be covered by the racking while still meeting building code requirements.

Across the United States, the average solar panel installation requires about 300 – 400 square feet of space. If your roof doesn’t have enough space available to accommodate the full system, installers often recommend higher efficiency panels that generate more renewable energy per square feet compared to standard panels. These panels may be more expensive, but the added energy they provide will usually make up for the added cost over time. Your installer will be able to provide you savings projections to help identify whether your home would benefit from high efficiency panels.

Solar installers use several different tools for estimating the viability of solar system designs. Installers can combine the data from these tools with aerial imagery to lay out solar system designs on your roof and calculate how much electricity the system will generate.  

Most customers will get the most out of their solar system when it is designed to offset 100% of their annual electric bill, so solar installers will ask for twelve months of energy bills in order to calculate exactly how much solar energy you’ll need. They can plug this level of energy into their calculations so you can evaluate exactly how much of your annual bill would be offset by the solar system.

The optimal system size will differ depending on your geographic location and roof profile. Since solar panels harvest energy from the Sun’s rays, if you have a south-facing roof, your panels will generate more energy compared to solar panels on rooftops that are north facing south or are heavily shaded. This idea of roof orientation is a critical factor in solar power system design.  

It is common for rooftops to have some minor shading, either from nearby buildings, neighboring trees, or large chimneys. As a result, solar panel installers may decide not to cover these shaded areas with solar panels to maximize the performance of the solar systems. Installers may also recommend specific equipment designed to perform optimally even with light shading. These shading optimized systems usually use microinverters or power optimizers to help limit the effect of shading on the overall performance of the solar system.

Other factors such as the structural strength of your home’s rooftop, the condition of your electrical system, or the eventual effects of shading may require that a solar engineer visits your home for an in-person assessment to collect key information in order to develop a system design that will perform optimally. All these factors are carefully considered when designing a solar system and they all play a key role in determining the solar system’s performance.

Once your solar installer has presented you with the designs that would work best for your home, you can pick the one that best meets your budget and energy needs. The next step is to sign a contract, evaluate your financing options, and start the solar system installation process.