Solar arrays: What are they & why do you need them?

The solar array is the most important part of a solar panel system – it holds all the panels in your system, collects sunlight, and converts it into electricity. In this article, we'll share some common questions to ask yourself before installing a solar panel system on your home and ensure you get the most productive array possible.

A solar array is a collection of multiple solar panels that generate electricity. When an installer talks about solar arrays, they typically describe the solar panels themselves and how they're situated – aka the entire solar photovoltaic, or PV system. To create solar energy, sunlight must hit your panels' photovoltaic cells. The sunlight sets electrons in motion, producing direct current (DC) electricity. Your array is connected to an inverter or multiple inverters, which convert the DC electricity generated by the solar cells in your panels into usable alternating current (AC) electricity.

The term solar array is often also used to describe large-scale solar projects; however, it can refer to just about any grouping of solar panels. In this article, we'll focus on residential solar arrays, which are typically located on your roof. Check out our utility-scale solar panel systems article for more information about large-scale solar arrays

It's essential to ask any installer about the system design and the location they propose installing the solar panels. If you're in the Northern Hemisphere, a solar array facing directly south will produce more electricity than one facing west, east, or north because it will receive more hours of sunlight.

Rooftops are a common choice for installing solar panels, but they're certainly not the only ones. If you have plenty of land and sunshine, consider installing a ground-mounted system instead. The dimensions of a roof don't constrain ground-mounted arrays, so you can face and tilt the panels optimally for maximum production and produce more electricity over time.

In addition to rooftops, solar arrays are sometimes located on other structures like carports and gazebos. These installations aren't as common, so you might have to search for an installer in your market that can design and install this type of system. There may also be higher costs associated with a stand-alone structure because of the additional components required for the installation.

A typical home needs between 17 and 21 solar panels to cover all of its electricity needs; however, the exact number depends on the size of your electricity bill (among several other factors). Your savings will be the greatest if you try to cover as close to 100 percent of your electricity usage as possible – this may mean you have to install a few more or higher wattage panels than your next-door neighbor if you have different energy needs for your home.

The number of panels you need also depends on the location of the panels, both regarding your geographic location and the design itself. Regarding geography, the same solar panel in California will produce more electricity than in New York because California gets more sunshine over a year. Installers take your geography into account when estimating the production of your solar panel system and will propose a design accordingly.

The physical location of your array and the direction it faces is also important. If your roof faces east/west, you'll need to install more panels to reach the same production as a south-facing system.

In some cases, your installer will recommend a solar panel system made up of multiple arrays that are connected and supply electricity to the same meter. However, multiple arrays can result in higher installation costs because of the additional labor requirements.

In addition, if you install multiple arrays facing different directions, you may want to consider using either power optimizers or microinverters as your inverter solution. Also known as module-level power electronics (MLPE), power optimizers and microinverters help complicated solar panel systems produce electricity efficiently by optimizing the production of each panel. In contrast, with a standard central string inverter, one panel underperforming can lower the production of the other panels on the same circuit.

You may be considering adding solar panels to your system if you plan to increase your electricity consumption. Whether you're considering purchasing an electric vehicle (EV), installing a hot tub, switching to air-source heat pumps, or any other home upgrades, there are plenty of reasons to expect your electricity costs to increase. If you have additional space available for more panels, it's certainly possible to add to your system at a later date – but you'll want to keep a few things in mind:

Choose efficient equipment

First, if you have limited space, you should consider paying more for high-efficiency and high-power output equipment – like panels from SunPower, Panasonic, or REC – when you install your first array. This maximizes your overall electricity production while saving space for new panels in the future.

Use your original installer

Next, ask your installer if they have performed add-on projects. Some installation companies will shy away from doing add-on projects if they don't install the original system because they're worried about conflicting warranties. It's usually easier to work with the company that did the initial installation to avoid any issues.

Plan for future electricity consumption

Finally, if you're certain that your electricity use will increase soon, you may want to consider oversizing your system initially to avoid an add-on project in the future. By doing so, you'll save on costs for labor and permitting. You'll also be able to take maximum advantage of incentives available now that may not be down the line, such as the 30 percent federal tax credit for solar that's set to drop to 26 percent in 2032.

At EnergySage, we always recommend comparing your options. Sign up on the EnergySage Marketplace to receive quotes from multiple pre-vetted installers to start generating renewable energy with your own solar array. If you have strong preferences about your solar panel system, make a note in your account so installers can tailor their quotes accordingly. If you'd like to start your solar research with an estimate of costs and savings, try our Solar Calculator.