large solar array in a field

What is a solar array?

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The most important part of a solar panel system is the solar array. It holds all of the panels in your system, which is where sunlight is collected and converted into electricity. Here are some common questions to ask yourself before installing a solar panel system on your home, and to make sure you get the most productive array possible.

What is a solar array?

Simply put, a solar array is a collection of multiple solar panels that generate electricity as a system. When an installer talks about solar arrays, they’re typically describing the solar panels themselves and how they are situated. Sunlight hits the panels in an array and produces direct current (DC) electricity. The array is connected to an inverter system, and the inverter converts the DC electricity t  usable alternating current (AC) electricity.

The term solar array is often also used to describe large-scale solar farms, however, it can be used to describe just about any grouping of solar panels. For the remainder of this article, we’ll discuss residential solar arrays, which are typically located on your roof. For more information about large-scale solar arrays, you can read about utility-scale solar panel systems.

Does it matter where your array is located?

It’s certainly important to ask any installer about the system design and the location they’re proposing to put 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 to locate your solar panels, but they’re certainly not the only one. If you have a lot of land available with plenty of sunshine, then you might consider installing a ground mount instead. Ground-mounted arrays are faced and tilted optimally for maximum production, rather than being constrained by the dimensions of a roof, so they can actually produce more electricity over time.

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

How many panels do you need in your array?

The number of solar panels you need depends on the size of your electricity bill (among a number of 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 that you have to install a few more panels than your next-door neighbor if you have different energy needs for your home.

The number of panels you need to cover your electricity usage also depends on the location of the panels, both in regards to your geographic location and the design itself. As far as geography goes, one solar panel in California is going to produce more electricity than a solar panel in New York, all other things being equal, because California gets more sunshine over the course of 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 the array and the direction it faces is also an important factor. If your roof faces east/west, you’ll need to install more panels to reach the same amount of production that you would need if your roof was facing due south.

Can you install more than one solar array?

In some cases, your installer will recommend a solar panel system made up of multiple arrays that are connected and supplying electricity to the same meter.

Multiple arrays can result in a higher installation cost because of the additional labor requirements to install them. In addition, if you install multiple arrays that are 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 solar panel systems with complicated designs produce electricity efficiently. With a standard central string inverter, one panel underperforming can affect the production of the other panels on the same circuit.

Can you add on to your solar array down the line?

You may be considering adding solar panels onto your system in the future if you have plans to increase your electricity consumption down the line. Whether you’re thinking of purchasing an EV, installing a hot tub, switching to air source heat pumps, or any number of other home upgrades, there are plenty of reasons to expect your electricity costs to increase in the future.

If you have additional space available for more panels, it’s certainly possible to add onto your system at a later date. But, it is important to keep a few things in mind.

First, if you have limited space, you may want to consider paying a little more for high-efficiency equipment when you install your first array. This maximizes your overall electricity production while saving space for new panels in the future.

Next, ask your installer if they have performed add-on projects. Some installation companies will shy away from doing add-on projects if they didn’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 in order to avoid any issues.

Lastly, if you are 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 26% federal tax credit for solar that’s set to drop to 22% after 2022 and expire after 2023 for residential systems.

How to get your own solar array

At EnergySage, we always recommend comparing your options. Sign up on the EnergySage Marketplace to get quotes from multiple pre-screened and vetted installers. If you have any strong preferences about your solar panel system, simply note it in the account so installers can tailor their offering to your desire. If you’d like to start out your solar research with an estimate of costs and savings, try our Solar Calculator.

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About Kerry Thoubboron

Kerry has worked in solar for more than 6 years, starting her career as an Energy Advisor dedicated to helping customers compare their options and make well-informed solar decisions. She graduated from Boston University with a degree in Environmental Analysis and Policy. Outside of work, you can find Kerry snowboarding, watching The Office, or having passionate debates about which New England state is best (spoiler: it's Vermont).

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