Last Updated: April 9, 2026
Key Takeaways
- The right commercial solar system size depends on your annual kWh usage, available roof space, and energy goals, not a generic formula.
- The average U.S. commercial building uses 22.5 kWh per square foot per year (U.S. Department of Energy).
- Commercial solar grew 6% in 2025, adding 2,345 MW of new capacity nationally (SEIA, 2025).
- With the 30% federal tax credit, MACRS depreciation, and net metering, most businesses see full payback in 5 to 10 years.
Getting solar right for your business comes down to one thing: accurate sizing. A system that’s too small won’t deliver the energy savings you’re after. One that’s too large ties up capital without proportional return. At Sundance Power Systems, our 5 Step Design Process starts with listening to what your business actually needs, then designing a system that fits.
We’ve been sizing and installing commercial solar systems throughout Western North Carolina and Upstate South Carolina for 30 years. Here’s how we approach it, and what you should know before your first conversation with a solar provider.
Your Electric Bill Is the Starting Point for Commercial Solar Sizing
Every commercial solar system design begins with the same question: how much electricity does your business actually use?
The answer lives in your utility bills. Specifically, your kilowatt-hour (kWh) consumption over 12 months. That full-year view matters because energy use changes with the seasons. A restaurant pushing air conditioning through July looks very different from that same building in February.
According to the U.S. Department of Energy, the average commercial building in the United States consumes about 22.5 kWh per square foot per year (Department of Energy). But that average hides a wide range depending on what type of business you’re running.
For Duke Energy customers in our region, monthly statements break out kWh usage clearly. Pull together 12 months of bills and you’ve got the baseline our design team needs to start working.
Energy Use by Business Type: What to Expect
Different businesses have very different power profiles. Here’s a general sense of what we typically see across our service area:
Small retail or office space (2,000 to 5,000 sq ft): Roughly 20,000 to 50,000 kWh per year. A system in the 15 to 35 kW range often covers most of that usage. Offices tend to use around 15 kWh per square foot annually, driven primarily by lighting, HVAC, and computers (AltEnergyMag).
Restaurants and food service: 50,000 to 150,000+ kWh per year. Commercial kitchens, walk-in coolers, and ventilation systems drive heavy demand. Restaurants can exceed 30 kWh per square foot due to refrigeration and cooking equipment (Great Energy 1, 2025). Solar offsets a meaningful share of that cost, though 100% offset typically requires substantial roof space.
Warehouses and light manufacturing (10,000+ sq ft): 100,000 to 500,000+ kWh per year. These facilities often have large, flat roofs that are ideal for solar arrays. A warehouse averages about 9 kWh per square foot (AltEnergyMag), but the sheer square footage adds up fast. Our 81.85 kW installation at Hanvey Engineering in Easley, SC is a good example of a manufacturing facility taking full advantage of available roof space.
Large manufacturing and institutional: 500,000 kWh and up. The 710 kW system we installed at Sierra Nevada Brewing in Mills River, NC was designed to make a serious dent in the energy needs of a facility that size, with panels covering both rooftops and parking canopies.
These are ballpark ranges. Your actual usage is what drives the design.
Why Load Analysis Matters More Than Square Footage
It’s tempting to size a system based on how much roof you have. Roof space matters, but it’s not the starting point. A proper load analysis, which is a detailed look at what’s actually consuming electricity in your building, is what separates a well-designed system from a guess.
Your HVAC system, lighting, refrigeration, machinery, computers, EV chargers, water heating… each pulls power at different rates throughout the day. Some loads run constantly. Others spike at certain times. Heating and cooling alone accounts for nearly 40% of all commercial energy use in the United States (Diversegy, 2024). Understanding when and how your building uses power is how we design a system that matches your real energy profile.
This is the second step in our design process, and it’s one of the most important. Our Renewable Energy Consultants dig into the details so the system we propose actually performs the way you need it to.
“We take great pride in designing and installing systems that are reliable and user-friendly, providing our clients with decades of trouble-free renewable energy.” – Dave Hollister, President and CEO, Sundance Power Systems
Roof Condition, Orientation, and Shading for Commercial Solar
Once we understand your energy usage, we assess the physical space. For rooftop commercial systems, a few factors come into play:
Roof condition and age. If your roof needs replacement in the next five to ten years, it makes sense to address that before installing panels. Solar panels last 25 to 30 years. You don’t want to remove them halfway through their lifespan to re-roof the building.
Orientation and tilt. South-facing roof sections capture the most direct sunlight in Western North Carolina and Upstate South Carolina. East and west-facing arrays can work well too, depending on the situation. Flat commercial roofs give us flexibility with ballasted racking systems that can be angled for better production. Our GNT North America project used a PanelClaw ballasted system on a large flat warehouse roof with 574 bifacial modules.
Shading. Trees, adjacent buildings, rooftop HVAC units… anything that casts a shadow reduces output. We use satellite imagery and on-site evaluation to map shading patterns throughout the year.
Structural capacity. Solar panels and racking add weight to your roof. Most commercial roofs handle it fine, but we verify structural capacity during our site evaluation.
For businesses with limited roof space, ground-mount systems are an option when the property allows for it.
Grid-Tied, Battery Backup, or Both?
Most commercial solar systems in our area are grid-tied, meaning they connect to the utility grid. When your panels produce more electricity than your business is using, the excess flows to the grid and you receive credit on your bill through net metering.
But more businesses are adding battery storage, especially after Hurricane Helene showed how vulnerable our region’s power grid can be. A battery backup system keeps critical loads running during an outage: security systems, refrigeration, servers, emergency lighting, and communications equipment.
According to SEIA, lithium iron phosphate (LFP) batteries now represent 91% of all storage deployed in 2025, up from roughly 50% market share at the start of the decade (SEIA, 2026). The technology is more affordable and longer-lasting than it’s been, and the federal tax credit now applies to standalone battery purchases as well.
The decision between grid-tied only and grid-tied with battery backup affects system sizing and cost. Our design team helps you weigh the tradeoffs based on your priorities and budget.
Financial Incentives That Affect Commercial Solar Sizing Decisions
System size directly impacts cost, but it also determines your return. A well-sized commercial solar system typically pays for itself within 5 to 10 years, depending on energy costs, incentives, and financing structure.
Here’s what helps close that gap:
Federal Investment Tax Credit (ITC): 30% of total system cost, including battery storage. This is a dollar-for-dollar credit on your federal tax liability, available through 2032 under the Inflation Reduction Act. For a $250,000 commercial system, that’s $75,000 directly off your tax bill.
MACRS Depreciation: Commercial solar qualifies as five-year property under the Modified Accelerated Cost-Recovery System, allowing businesses to depreciate the full cost over five years.
USDA REAP Grants: If your business qualifies as a rural small business or agricultural operation, the REAP program can cover up to 50% of eligible project costs. This is a real opportunity for farms and rural businesses across our region.
Net metering credits: Excess solar production reduces your electric bill month to month.
South Carolina state tax credit: Businesses in SC can claim a 25% state tax credit on top of the federal credit, up to $3,500 per year with a 10-year carry-forward.
When you stack these incentives together, the effective cost of a commercial system drops significantly. Sundance walks every commercial client through the financial picture as part of our proposal process. We always recommend consulting a tax professional to make sure you’re structured to capture every available benefit.
“Solar, now a $60 billion industry, is adding more new capacity to the US grid than any other fuel source amid the largest increase in electricity demand since World War II.” – Abigail Ross Hopper, President and CEO, Solar Energy Industries Association (SEIA)
How Sundance Sizes Your Commercial Solar System
We don’t guess. We don’t use a cookie-cutter formula. Every commercial system we design goes through our 5 Step Design Process:
Step 1: Site Visit. We visit your property, inspect the roof or potential ground-mount area, and get a firsthand look at your facility.
Step 2: Load Analysis. We review your utility history, identify your consumption patterns, and talk through your energy goals.
Step 3: Preliminary Design and Estimate. Based on the data, our design team creates an initial system layout with projected performance and cost.
Step 4: Design Review. We walk through the design together, adjust as needed, and make sure the system fits your expectations and budget.
Step 5: Final Decision and Proposal. Once everything looks right, we deliver a final proposal covering system specs, projected savings, incentive details, and a timeline for installation.
“It was finally time to go solar. After a lot of research, quotes, phone calls and in person meetings from several companies, we went with Sundance Power Systems. What set them apart is that they really listened to my needs for the system and followed through.” – Blair E., Sundance customer, 2024
This process is how we’ve delivered commercial solar across the Carolinas for 30 years, from a 9.45 kW system on a small mixed-use building to the 710 kW installation at Sierra Nevada Brewing. Only 3.5% of commercial buildings in the United States currently have solar installed (Diversegy, 2024), which means there’s enormous room for businesses to start saving. Solar accounted for 54% of all new electricity-generating capacity added to the U.S. grid in 2025 (SEIA, 2025).
Summary
The right commercial solar system starts with accurate data about your building’s energy use, not guesswork. A proper load analysis, site evaluation, and clear understanding of available incentives are what separate a system that delivers real returns from one that underperforms. With the federal ITC at 30%, MACRS depreciation, and potential state credits, the financial case for commercial solar is strong right now. Sundance has been sizing these systems for businesses across Western NC and Upstate SC since 1995. Contact us at (828) 645-2080 or get a quote to start the conversation.
Frequently Asked Questions About Commercial Solar System Sizing
How many solar panels does a typical commercial building need?
It depends entirely on your electricity usage and available space. A small office might need 40 to 90 panels, while a manufacturing facility could require 500 or more. Modern commercial panels typically produce 400 to 450 watts each, so a 100 kW system would need roughly 225 to 250 panels.
How long does it take for a commercial solar system to pay for itself?
Most businesses in our region see payback in 5 to 10 years, depending on system size, energy costs, and incentives claimed. After payback, your electricity from those panels is essentially free for the remaining 15 to 20+ years of the system’s life.
Can my business go completely off-grid with solar?
Technically yes, but it’s rarely cost-effective for commercial properties. Most businesses benefit more from a grid-tied system with optional battery backup for critical loads during outages.
Does the federal tax credit apply to commercial solar installations?
Yes. The 30% Investment Tax Credit applies to both residential and commercial solar systems, including battery storage. It’s a dollar-for-dollar reduction in your federal tax liability, available through 2032. Learn more on our tax credits page.
What if my roof isn’t big enough for the system I need?
Ground-mount systems are an option for businesses with available land. Parking canopy systems are another possibility, as we demonstrated at the Sierra Nevada Brewing facility where panels cover both the rooftop and parking lot canopies.
Does Sundance handle permitting and utility paperwork for commercial projects?
Yes. We manage the full process from design through installation, commissioning, and all interconnection and permitting paperwork. Our team handles the details so you can focus on running your business.
How does net metering work for commercial solar customers in North Carolina?
When your panels produce more electricity than your business uses at any given moment, the excess flows to the utility grid. Your utility credits you for that production, which offsets the power you draw during lower-production periods like nighttime or cloudy days.
Is solar financing available for commercial installations?
Yes. Sundance offers financing options through our lending partners, and many businesses also use direct purchase, SBA loans, or USDA REAP grants depending on their situation.