Solar quotes vary from four-page glossy brochures to 40-page engineering documents. Length doesn't reliably indicate quality. What matters is whether the seven sections below are present and complete. If they aren't, you're looking at a sales document, not a quote.
The seven sections of a real quote
- System summary (what's being supplied)
- Bill of materials (specifically what hardware)
- Production model (how much electricity it'll make)
- Warranties (what's covered, by whom, for how long)
- Financial summary (cost, savings, payback)
- Scope and exclusions (what's included, what isn't)
- Payment schedule (when money moves)
Below, what each should contain.
System summary
A one-page overview at the top. Should include:
- System size in kWp (the headline number)
- Number and wattage of panels
- Inverter capacity and type (string, micro, hybrid)
- Mounting type (pitched roof / flat roof / ground-mount, and specific product)
- Grid tied or hybrid; battery capacity if included
- Expected annual production (ballpark)
- Installation location and scope
If any of these are vague ("tier-1 panels," "premium inverter"), the quote is incomplete.
Bill of materials
Every component, by specific manufacturer and model. The test: can you look up the part numbers online and find their data sheets?
For each component, expect:
- Make and model
- Quantity
- Specifications (for panels: wattage, efficiency, temperature coefficient, dimensions, weight; for inverters: capacity, efficiency, MPPT channels, warranty terms)
Extra points if the quote includes links to manufacturer datasheets or warranty documents.
Some quotes include a clause allowing the supplier to substitute "equivalent" components if the specified ones are unavailable. Reasonable on rare occasions; abused often. Insist on written approval for any substitutions, and require that substitutes meet or exceed the original spec.
Production model
This is where good quotes separate from bad ones. A real production model shows:
- Expected annual production in kWh
- Monthly production breakdown (not just annual average — monsoon regions swing 30–50%)
- Assumptions used: peak sun hours, orientation, tilt, shading losses, soiling losses, system efficiency, panel degradation
- Performance guarantee (if any) — some suppliers guarantee production within X% of model; most don't
A quote that says "expected annual production: 12,500 kWh" without showing how they got there is guessing or optimising. Ask for the model assumptions. If they can't provide them, the number is sales, not engineering.
Warranties
A complete warranty section should have line items for:
- Panel product warranty (years and terms)
- Panel performance warranty (degradation curve)
- Inverter warranty (years, extensions, who handles claims)
- Mounting warranty
- Installer workmanship warranty (years and scope)
- Labour coverage for warranty replacement (is it covered, or just parts?)
Any warranty mentioned but not detailed isn't one. "25-year warranty" without terms is a slogan.
Financial summary
This section varies most between quotes. A serious one includes:
- Total system cost (all-in, including installation and commissioning)
- Breakdown by hardware, design/permitting, installation, other
- Expected annual savings with stated rate assumptions
- Payback period (years)
- 25-year cash flow table with inverter replacement at year 10–12 included
- IRR and NPV (for commercial quotes)
- Sensitivity analysis (how does payback change if rates stay flat, etc.)
Quotes with a single "payback period" number and no cash flow table are hiding their assumptions.
Ask the supplier to show the payback under two scenarios: (1) electricity rates stay flat for 25 years; (2) production comes in 10% below model. If the payback is still reasonable under both, the quote is probably honest. If either scenario destroys the economics, the baseline is depending on aggressive assumptions.
Scope and exclusions
Often the most-skipped section, often the one with the most surprises. Watch for:
- Grid-connection application and utility fees — included or extra?
- Permits and inspection fees — included or extra?
- Structural upgrades if the roof needs them — included or extra?
- Electrical panel upgrades if needed — included or extra?
- Monitoring hardware and data subscription — included for how long?
- Commissioning and initial performance testing — included?
- Post-install training for you on the monitoring app — included?
- Tree trimming, antenna relocation, or other site prep — included?
Any that show up as "extra" should have either a fixed price or a clear provisional sum. Open-ended exclusions become arguments later.
Payment schedule
Reasonable structures:
- 20–30% deposit to confirm order
- 40–50% on material delivery to site
- 20–30% on commissioning and grid-connection
Red flags:
- More than 50% upfront before any materials are on site
- 100% on signing
- Payment schedules tied to vague milestones ("substantial progress") instead of observable events
- Penalties for late payment that exceed industry norms