Quick definition
An array is the umbrella term for every panel in your solar installation, working together. Panels get grouped into strings, and strings make up the array, which then connects to one or more inverters to convert the power into something your home or the grid can use.
When an installer talks about "your array," they mean the whole system on your roof, not any single panel.
At a glance: the average US residential array has climbed to around 12 kW as of 2026, typically 16 to 23 panels given today's higher-wattage panels, though this varies widely by roof size and household usage.
Why it matters
How an array is laid out affects real-world performance more than most homeowners expect. Panels wired into the same string perform at the level of the weakest panel in that string, so a single shaded panel can drag down output across its whole string, not just itself.
This is why roofs with multiple facing directions, say a section facing south and a section facing west, usually get split into separate strings, each tied to its own MPPT input on the inverter, a layout question the MPPT count vs array layout calculator can help work through. That way a partly shaded west-facing section doesn't pull down the better-performing south-facing section sharing the same string.
Array size also drives most of the big system decisions: how many panels you need, how many strings those panels split into, and how many inverters or MPPT inputs the installation needs to handle it all without leaving performance on the table. EnergySage's own marketplace data puts the current US average at around 12 kW, 16 to 23 panels given today's higher-wattage modules, a real shift from just a few years ago that their H2 2025 marketplace report traces to both panel efficiency gains and shifting incentive timelines. The U.S. Energy Information Administration's solar explainer describes how panels are grouped into arrays, and how the layout affects output.
Where you'll see this
Once you know your panel count, best worked out with the solar panel calculator, the string sizing tool helps split your array into strings that match your inverter's voltage window and MPPT inputs.
If your roof has multiple usable planes, the array tilt angle optimizer compares expected output across different tilt and orientation combinations before you finalize the layout.
This term comes up constantly in solar quotes, in any discussion of roof layout, and any time you're comparing system sizes across proposals. The Department of Energy's homeowner guide walks through the equipment in a home solar setup, from the array on the roof to the inverter inside.
Related terms
Frequently asked
A panel is one physical solar module. A string is several panels wired together in a series. An array is the complete system, which can be one string or several strings combined, depending on the system's size.
Yes, and it's common on roofs with more than one usable plane. Each direction typically needs its own string and often its own MPPT input, so the inverter can optimize each section separately instead of averaging mismatched output together.
It's the main factor, but not the only one. Panel wattage, tilt angle, shading, and orientation all affect how much of that rated array capacity actually converts into usable power over a year.
A single inverter with multiple MPPT inputs can often manage several strings or even separate arrays with different orientations. Larger commercial arrays sometimes use multiple inverters instead, each handling its own section.