What is a solar array and are they right for your home?
Updated
Solar panels connected to form solar arrays. Image source: RMIT University
You’re curious about renewable energy, and you’ve heard of solar panels - but you’re not sure what a solar array is. Worry not, you’re in the right place. In this article, you'll learn everything you need to know about solar arrays, how much a solar array will cost, and whether they're right for your home.
What is a solar array?
Simply put, a solar array is a collection of solar panels wired together to capture sunlight and produce electricity.
Solar arrays combined with one or more solar inverters (and, optionally, a battery) become a fully functional solar power system. As part of the solar power system, a solar array generates electricity that can power a house or be exported to the grid.
What are solar arrays made of?
A solar array is a collection of solar panels wired together into a circuit.
Solar panels, in turn, are a collection of photovoltaic (PV) solar cells, covered with protective glass and held together with a metal frame. Solar cells are made of semiconductor material, typically silicon, that is sliced incredibly thin.
Individual solar cells generate electrical power using the photovoltaic process: photons in sunlight separate electrons from the silicon, generating an electric charge. This process is why solar panel systems are also called ‘PV systems.’
The number of solar panels used depends on the power output, or wattage, of each individual panel, as well as the total system size, desired. For example, a 7,000 watt (7 kW) residential solar system might be built using 28 solar panels with an output of 250 watts each, or just 19 solar panels with an output of 375 watts each.
Learn more: How do solar panels work?
All of the components other than the solar array are sometimes referred to collectively as the balance of system (BOS).
How do solar arrays work?
Thanks to the durability of solar panels, a solar array can be used for energy production for 25 years (their warranted life) or longer. Energy production occurs without the use of moving parts, fuel, or any other kind of intervention from the owners.
Here’s a brief description of how a solar array can provide power for a home solar energy system:
- Energy creation: Sunlight hits the solar cells in the array, activating them and generating Direct Current (DC) electricity.
- Energy conversion: The DC power then travels to an inverter, where it is converted into Alternating Current (AC) electricity usable by the home.
- Energy consumption: The 120/240 volt AC power supply is then either used on-site (i.e. by the home) or exported to the grid, from which it can be distributed to others who need power.
Where can you put solar arrays?
Solar arrays can be installed anywhere with good access to sunlight.
The most common location for a solar array installation is atop the roof of a house. It should ideally be on a south-facing section of the rooftop. In the U.S., solar arrays pointed towards the south receive the most sun, and thus generate the most power.
Another option is to install a solar array on ground mounts. This option is commonly used by solar farms or in more rural locations, where land is generally cheaper.
Solar arrays can be mounted on structures other than roofs. Solar canopies are one such option, as are solar pergolas, patios, and gazebos.
Heading out for the weekend? Solar arrays can also be installed atop vehicles. Solar energy has long been a popular option for RVs, while boats are starting to incorporate solar arrays, too.
Furthermore, solar arrays, paired with energy storage systems such as solar batteries, have long been used in off-grid settings such as hunting cabins.
Finally, there are more niche locations for solar arrays, such as those integrated into buildings.
How to size a solar array
The term ‘solar array size’ is used to describe a solar panel system’s capacity to produce electricity.
A solar array sized 300 watts can produce 300 watts of electricity, while a solar system sized 6 kilowatts will produce 6,000 watts – under standard conditions.
Figuring out what size solar array is right for you depends on several factors such as your energy consumption, available roof space, and the amount of sunlight where you live (which is measured in peak sun hours).
Let’s assume you want a solar array big enough to wipe out your electricity bill. In that case, you may want a solar array that can produce 1,000 kWh of electricity a month (the average U.S. home consumes this much, according to the EIA, but your energy needs may vary).
Here are the solar array sizes you would need to produce 1,000 kWh in different parts of the country:
| Region and state | Average daily peak sun hours | Average monthly peak sun hours | Solar array size |
|---|---|---|---|
| West: California | 6.7 hours | 201 hours | 5 kW |
| South: Texas | 5.6 hours | 168 hours | 6.2 kW |
| Midwest: Illinois | 4.3 hours | 129 hours | 7.8 kW |
| Northeast: New Jersey | 4.1 hours | 123 hours | 8.1 kW |
In terms of the number of panels, the solar array sizes above (i.e. 5 kW-8.1 kW) would need between 16 and 26 solar panels - assuming the use of 320-watt panels.
In terms of space, a solar array would require between 277 and 450 square feet.
Utility-scale solar arrays, or solar farms, on the other hand, might comprise hundreds or even thousands of solar panels.
How much do solar arrays cost?
The average cost of a complete home solar panel system in the U.S. is between $18,000 and $20,000. This figure is based on a pre-incentive cost of between $2.75 and $3.35 per watt of solar installed, as per our cost data.
Out of that, the equipment for the solar array will account for between $5,800 and $7,850.
The remainder of the total system cost comprises mainly the cost of the solar inverter(s) and the cost of the installation itself.
Learn more: Solar panel cost
Is installing a solar array a good idea?
Thanks to the low cost of solar panels, various solar incentives, and long warranties, solar arrays are a worthwhile investment for most homeowners.
Solar panel systems save the average homeowner between $900 and $1,200 a year on utility bills. This means the average homeowner will have a solar payback period of between 8 and 11 years. Then, they’ll be enjoying completely free solar electricity for another 15 years!
Your actual savings from going solar will depend on the size of your system, the cost of electricity in your region, and how many kilowatt-hours of electricity you use. It also depends on what kind of net metering policy is available in your area.
Luckily, our solar savings estimator takes all of these factors into account when determining how much you will save with solar.
Key takeaways
- A solar array is a collection of solar panels, wired together into a circuit. Combined with the ‘balance of system’ components - which includes solar inverters - it forms a solar power system.
- The solar array generates DC power, which is passed to an inverter for conversion into AC electricity usable by your home.
- Solar arrays can be installed on a variety of structures and settings; for residential installations, the roof is the most common place to put them.
- A solar array that can power an average household would require between 21-34 panels, depending on panel size and factors specific to your home.
- A complete solar panel installation costs between $18,000 and $20,000 before incentives; of that, the solar array accounts for $5,800-$7,850.
- Going solar can result in substantial savings, but we recommend you check if the math works out for you before taking the plunge.
Zeeshan Hyder
SolarReviews Blog Author
Zeeshan is passionate about promoting renewable energy and tackling climate change. He developed these interests while studying at beautiful Middlebury College, Vermont, which has a strong focus on sustainability. He has previously worked in the humanitarian sector — for Doctors Without Borders — and in communications and journalism.