Compare Commercial Solar Quotes & Save

If you are comparing commercial solar quotes right now, you have likely discovered that three quotes for the same building can vary by $20,000 or more. One says $85,000 for 100kW. Another says $110,000. A third quotes $78,000 but omits the switchboard upgrade that you will inevitably need.

The problem is that most commercial solar quotes are not comparing the same thing. They use different equipment tiers, different production assumptions, and different scopes of work. Without normalising these variables, you are not comparing prices, you are comparing specifications you cannot see.

Here is what to look for before signing any commercial solar proposal.

Commercial solar is not a single category. The regulatory and financial structure changes at three distinct capacity points. If your quotes span these thresholds, they are not comparable.

Under 30kW

This operates under the same framework as residential solar. You claim STC rebates (Small-scale Technology Certificates) upfront at point of sale, and the grid connection process is straightforward.

The risk: Many residential installers attempt to "scale up" to 30kW commercial without understanding three-phase power, commercial metering, or the monitoring requirements of business operations. A 30kW system generates roughly 120kWh per day. If the installer has not modelled your consumption intervals (30-minute data), they cannot predict your self-consumption rate, and therefore cannot calculate your actual savings.

30kW to 100kW

You are now in specialist territory. These systems require network protection equipment and formal DNSP (Distributed Network Service Provider) permission to connect. The paperwork is non-trivial, and a standard residential installer will often subcontract this piece, creating accountability gaps.

Pricing reality: As of February 2026, quality commercial solar systems in this range cost $1,000–$1,300 per kW installed, net of STC rebates. Add 15–20% if your roof requires power optimisers or microinverters for complex geometry or shading.

Over 100kW

This is where the incentive structure inverts. Systems over 100kW cannot claim STCs upfront. Instead, you register as an accredited power station and claim LGCs (Large-scale Generation Certificates) annually based on actual metered generation.

Critical distinction: A 100kW system installed in February 2026 receives approximately $41,650 upfront via STCs. A 101kW system receives $0 upfront. You must install NEM-standard metering, operate for 12 months, and then claim LGCs retrospectively. This changes your cashflow and payback calculation significantly. If one quote is for 99kW and another for 101kW, they are not financially comparable without modelling the LGC revenue stream.

Cost per watt (total price divided by system capacity in watts) is the standard comparison metric. But it only works if the underlying scope is identical.

Common distortions:

• DC vs. AC capacity: A "100kW system" might mean 100kW of panels with a 90kW inverter (DC oversizing), or 100kW AC output with 110kW of panels. These are different configurations with different production profiles.
• Scope exclusions: A quote at $0.85/W usually excludes switchboard upgrades. A quote at $1.05/W includes them. That is a $3,000–$8,000 swing buried in the exclusions clause.
• Equipment vintage: $0.90/W using older-model panels versus $1.00/W using current high-efficiency modules. The "cheaper" system produces less energy per square metre and may degrade faster.

To compare accurately, request itemised scope documents that separate equipment costs, electrical works, and compliance costs. Only then can you calculate true $/Watt.

If a quote lists "Tier 1 panels, 100kW," that is insufficient. Tier 1 is a bankability rating, not a quality specification. You need technical details.

What to verify:

Panel Efficiency: If you have a constrained roof (most commercial sites), efficiency ratings matter significantly. A few percentage points difference in efficiency translates to 10% more generation from the same roof area. Over 25 years, that compounds.

Temperature Coefficient: This determines summer performance. Quality panels lose around 0.30% power per °C above 25°C. Budget panels lose 0.40% or more. On a 45°C day (70°C panel temperature), that is a measurable output difference that affects your summer savings when air-conditioning loads are highest.

Warranty Structure: Look beyond the "25 year warranty" headline. Is it a product warranty (covering materials and workmanship) or only a performance warranty? Product warranties should cover replacement labour and transport, not just the panel itself.

Inverter Specification: Specify topology (string vs. power optimiser vs. microinverter) and warranty term. For commercial applications, 10 years is the minimum acceptable warranty; 20 years is available for premium units.

If three quotes estimate 160,000 kWh, 145,000 kWh, and 175,000 kWh annually for the same 100kW system, at least one is wrong.

Reality checks:

• Sydney: ~1,400–1,500 equivalent peak sun hours annually
• Melbourne: ~1,200–1,300 (July production is roughly 40% of January)
• Brisbane: ~1,500–1,600

Be wary of quotes using a flat 5.5 peak sun hours year-round without seasonal variation. This overstates winter production and understates the value of summer generation if your business has air-conditioning load.

"Monitoring included" covers a wide spectrum.

• Inverter-level: Shows aggregate system output. Suitable for residential. Inadequate for commercial fault-finding.
• Panel-level: Shows individual module performance via power optimisers or microinverters. Essential for commercial arrays over 30kW.

Why it matters: If one panel fails in a 100kW array, inverter-level monitoring will not detect it until annual production drops noticeably, costing thousands in lost generation. Panel-level monitoring identifies faults immediately.

IT Integration: If you operate a Building Management System (BMS) or energy management platform, ask about API access to monitoring data. Some platforms offer open API architecture for integration with facility management systems and automated ESG reporting.

Check the exclusions section carefully for:

• Switchboard upgrades: If your main switchboard lacks capacity or spare ways, upgrades cost $3,000–$8,000. Vague language like "if required" usually means "not included."
• DNSP application fees: $500–$2,000 for systems over 30kW depending on your network operator.
• Engineering certification: Required for systems over 100kW.
• Crane hire: Multi-storey commercial buildings often require crane access. Verify if included.

The STC scheme stepped down on January 1, 2026. A 100kW system now generates approximately 1,190 STCs versus 1,240 previously. At current market rates ($38 to $42 per STC), that is roughly $41,650 in upfront rebates, down about $1,750 from December 2025 pricing.

Next step-down: January 1, 2027 (to 6-year deeming), adding approximately $1,800 to net costs.

Battery incentive: Active since July 2025. Businesses can claim approximately $311 per usable kWh for battery storage, stackable with state incentives.