What Size Commercial Solar System Do You Need for Your Facility?

As a way of meeting environmental goals and cutting energy costs, more businesses are turning to renewable energy; commercial solar power is fast growing in appeal. Still, a lot of site managers ask, "What size solar system do I need?"

You have to consider more than simply how many panels might fit on your roof in order to determine the proper size. Your energy use, available space, budget, and return on investment also have to be considered. We will discuss in this post the main elements guiding your decision on the optimal solar system size for your company.

1. Understand Your Facility’s Energy Consumption

Start by looking at your company's energy use to determine appropriate system size. Usually showing in kilowatt-hours (kWh), your electricity bills contain this information.

Look at:

• Your monthly energy use
• Changes in usage during different seasons (like higher use in summer for air conditioning)
• Times of day when your energy use is highest

Pro Tip: To get an annual year average, gather past-due electricity statements over the past 12 months.

For example, 30,000 kWh used monthly by your company adds 360,000 kWh a year. This statistic can help you determine the power output required of your solar system.

2. Set Your Solar Offset Goal

Next, decide how much of your energy use you want your solar system to cover.

You have a few options:

• 100% Offset: You want solar to cover all your electricity use and eliminate your power bill.
• Partial Offset (50–75%): You want to lower costs but still use some power from the grid.
• Reduce Demand Charges: You use solar with batteries to cut down on expensive peak usage times.

Your goal will affect the system size. For example, your solar system must provide that same amount of energy annually if you wish to offset all of a 360,000-kWh annual use.

3. Know the Difference Between kW and kWh

Solar system size is measured in kilowatts (kW), but your energy use is measured in kilowatt-hours (kWh). These two are connected by how much sunlight your location gets.

Here’s a simple rule:

• 1 kW of solar can produce about 1,200 to 1,500 kWh per year, depending on where your business is located.

So, if your facility uses 360,000 kWh per year, you’ll need a system that’s around 240 to 300 kW in size.

You can use this formula to estimate your system size:

System Size (kW) = Annual kWh / (Production Ratio × 365)

• Usually between 4 and 5, the production ratio—that is, the daily sun hours your region receives, is what counts.
• 365 stands for the days in a year.

4. Check Your Roof or Land Space

Make sure you have enough space to install a system size before deciding upon one. Here's a brief overview:

• One kW of solar requires between eighty and hundred square feet.
• A 250 kW system requires perhaps 20,000 to 25,000 square feet.

Should your roof lack sufficient room, don’t worry

• Install a ground-mounted system
• Add solar canopies over your parking lot
• Make energy efficiency upgrades to lower your energy use and reduce the size of the system you need

5. Consider Panel Efficiency and Type

The type and efficiency of your solar panels also affect how big your system needs to be.

• Like monocrystalline high-efficiency panels, they produce more power in less space.
• Lower-efficiency panels require greater room to generate the same energy level.

So, if you decide on superior panels, you can set up a smaller system yet sufficient for your energy consumption.This is a great option if your roof or land space is limited.

6. Plan for Future Growth

If your business is growing—by adding equipment, more staff, or longer hours—your energy use will go up too.

Planning now can help you avoid extra costs later.

Here are a few smart steps:

• Install a slightly larger system to cover future needs
• Leave room to add more panels later
• Choose a solar inverter that can handle extra capacity in the future

Select Correct Solar System for Your Company

Gaining energy independence and reducing costs depend on selecting the correct size business solar system. Your energy use, objectives, roof space, and future business plans will all affect the optimum system.

With help from the best solar company in Cook County, you can build a system that works for you now—and grows as your business grows.

End Note

First consider your usage of energy, your desired outcome, and your available space to choose the appropriate solar system size. Also, think about your business growth. Planning well helps you save money and go green. With expert help, you can build a system that fits your needs now and grows with your business.