Undoubtedly, installing a commercial solar system in 2026 is one of the smartest long-term decisions any Australian business can make.
The underlying reason is pretty straightforward!
With electricity prices rising and sustainability becoming increasingly important, solar offers both financial savings and reputational benefits.
But one of the biggest questions business owners face early on is this:
What size solar system do we actually need?
Go too small, and you won’t see the savings you were hoping for. Go too big, and you risk overcapitalising or exporting excess energy at low feed-in rates.
Therefore, the right answer sits somewhere in the middle, and finding it requires more than just a guess.
In this guide, we’ll walk you through the three key steps that determine the right commercial solar system size for your business:
- Load analysis
- Roof or site assessment
- System design considerations
So let’s break down how to help you make a confident decision.
In this blog post:
- Step 1: Understanding Your Business Energy Load
- Step 2: Roof and Site Assessment – What Can Your Building Actually Handle?
- Step 3: Matching System Size to Business Needs
- Which Components Make a Great Commercial Solar System?
- Commercial Solar Batteries: Should They Affect System Size?
- Which System is Best for You? The Decision Behind the Panels
- Work with Cyanergy| Your Reputable Solar Installer
Step 1: Understanding Your Business Energy Load
This is where it all starts: before panels, inverters, or roof space are even discussed, the most important piece of the puzzle is your energy usage, not just how much you use, but when you use it.
Most businesses start by looking at their electricity bill and focusing on the total kilowatt-hours (kWh) used per month or year.
While that number matters, it’s only part of the story. Look beyond the total kWh because, for solar, the timing of your energy use is critical.
Consider an office, manufacturing facility, medical centre, or retail business that uses most of its electricity between 9 am and 4 pm; it is far more “solar-friendly” than one that uses most of its power overnight, such as cold storage or 24/7 operations.
Daytime vs After-Hours Usage
Before installing solar in your commercial property, ask yourself these:
- Are your main operations running during daylight hours?
- Do heavy machines, HVAC systems, or production lines operate while the sun is up?
- Does usage drop significantly after business hours?
The more energy you use during the day, the more of your business solar power you’ll consume directly, which is where the biggest savings are.
However, in some cases, exporting excess energy back to the grid is beneficial, but feed-in tariffs are usually much lower than what you pay for electricity. For greater financial outcomes, it’s better to install battery storage.
Interval Data: A Standard Method
In Australia, for a proper load analysis, solar professionals typically review interval data, typically 15 or 30 minute usage from your electricity retailer.
This data shows your:
- Daily load patterns
- Peak demand times
- Seasonal variations like summer vs winter
This level of detail allows system sizing to be tailored specifically to your business, rather than depending on rough averages.
Step 2: Roof and Site Assessment – What Can Your Building Actually Handle?
Once energy usage is understood, the next question becomes: where will the system go?
Thinking the same? Here’s your answer!
For most commercial systems, the roof is the obvious choice, but not all roofs are equal in size.
Available Roof Space
Solar panels take up space, and commercial systems can require significant space. The rough estimation says:
- 100kW system is needed for a roof of 500–600 square metres
- 200kW system is needed for a roof of 1,000–1,200 square metres
However, usable space is often less than the total roof area. Factors that reduce usable space include:
- HVAC units
- Skylights
- Roof access paths
- Setback requirements
- Fire safety regulations
Roof Orientation and Tilt
In Australia, north-facing panels generally produce the most energy, but east- and west-facing systems can still perform very well, especially for businesses with high daytime energy requirements.
Also, flat roofs are common on commercial buildings and offer flexibility, as panels can be tilted and oriented at any time using mounting frames.
Structural Integrity
One overlooked factor is whether the roof can physically support the system.
Commercial solar systems add weight, and while it’s usually well within limits, older buildings or lightweight structures may need a structural engineer’s approval.
Therefore, it’s far better to identify this early than be surprised later in the project.
Ground-Mounted and Carport Options
If your roof space is limited, don’t stress out, there are alternative ways, such as:
- Ground-mounted solar systems
- Solar carports over parking areas
Even these options can increase the system’s potential size but come with higher costs and planning considerations.
Step 3: Matching System Size to Business Needs
A common problem or misconception about solar panels is that bigger is always better. In reality, the best-sized system is one that aligns closely with your energy profile and business goals.
Self-Consumption
Do you know that the highest financial return comes from using solar energy directly on-site?
This is why many commercial systems are designed to offset 60-80% of daytime energy use, rather than 100% of total annual consumption.
Oversizing a system may result in:
- Excess exports at low feed-in tariffs
- Longer payback periods
- Underutilised capital
A perfectly designed system balances generation with actual energy demand.
Future-Proofing
Above all these, it’s also important to think ahead. Therefore, businesses should consider:
- Planned expansion
- Electric vehicle fleets
- New machinery or equipment
- Electrification of gas processes
Sometimes installing a slightly larger system, or choosing inverters that support future expansion, makes sense. The goal is to give scalability to your system, not blind oversizing.
Demand Charges and Peak Loads
Many Australian businesses pay demand charges based on their highest usage intervals.
While solar can help reduce daytime demand, it won’t always eliminate peaks, especially if they occur early morning or late afternoon.
In some cases, system design may focus on shaving peaks rather than just maximising total generation.
Which Components Make a Great Commercial Solar System?
A great commercial solar system comes down to a few essential components working together in sync.
Together, these ensure maximum energy output, safety, and return on investment. So, here’s a list:
- Solar panels: High-efficiency, durable, long warranties
- Inverters: Reliable DC-to-AC conversion and system control
- Mounting & racking: Strong, site-specific structural support
- Monitoring: Real-time performance tracking and alerts
- Safety & protection: Grounding, rapid shutdown, surge and fault protection
- Engineering & design: Proper system layout, permitting, and grid compliance
Operations & maintenance: Ongoing inspections to ensure long-term performance
Commercial Solar Batteries: Should They Affect System Size?
In Australia the battery storage is becoming more common, but it’s not always necessary upfront.
For many businesses, only solar panel systems offer the best return on investment. However, batteries tend to make more sense when:
- Evening or overnight usage is high
- Demand charges are significant
- Backup power is critical
- Time-of-use tariffs are extreme
Nowadays, most businesses choose to design a battery-ready solar system, allowing storage to be added later as prices in the Australian energy market decline.
Which System is Best for You? The Decision Behind the Panels
Now you might be wondering which solar system best fits your life.
We know every home needs a different solar story. So, beyond the numbers, choosing the right commercial solar system size is about confidence.
Panel Type Options
- Monocrystalline solar Panels: These panels have the highest efficiency and are ideal when the roof or land space is limited.
- Polycrystalline Solar Panels: They are also a strong choice for Australian businesses seeking a lower upfront cost and are satisfied with slightly reduced efficiency.
- Bifacial Solar Panels: They are super-efficient as they generate power from both sides. They are best suited for ground-mounted systems or highly reflective surfaces.
Selecting the right panel type helps ensure your commercial solar system delivers maximum performance and long-term value, so choose wisely.
However, in large-scale commercial properties, business owners often have many concerns. For instance:
- Making the wrong investment.
- Disrupting operations during commercial solar installation.
- Dealing with complex approvals.
- Understanding long-term performance.
Keep in mind that a good, accredited solar partner doesn’t just sell you panels; they explain the “why” behind the system size, show realistic projections, and design around how your business actually operates.
Work with Cyanergy| Your Reputable Solar Installer
Well, in the end note, if you are still looking for the right commercial solar system size, honestly, there’s no one-size-fits-all answer.
Every Australian business is different. Whether a warehouse in Victoria, a winery in Queensland, or a medical centre in New South Wales will all have very different solar needs, even if their electricity bills look similar.
Choosing the right commercial solar system size ultimately comes down to understanding your energy usage, making proper use of roof space, and designing a system that fits your business for the long term.
When those pieces align, solar stops being a guessing game and becomes what it should be.
It’s a smart, reliable investment that works quietly in the background while your business gets on with what it does best.
For more informative content and to schedule a proper energy audit, contact Cyanergy today!
Our solar experts will answer all your questions, making the energy transition process hassle-free and faster.
