The lowest final amount may exclude structure quality, protections, meter coordination, civil work, taxes, monitoring, or service. The highest amount is not automatically the best either. A fair comparison turns each quotation into the same checklist.
Normalize capacity, exact equipment, structure, electrical scope, approvals, taxes, subsidy treatment, generation assumptions, warranty, payment terms, exclusions, and after-sales support. Ask every bidder to clarify gaps in writing.
1. Confirm the design basis
- Annual units and bills used for sizing.
- Proposed capacity in kW and system type.
- Usable roof area and shade assumptions.
- Expected annual generation range and its calculation basis.
- Self-consumption and export assumptions.
- Sanctioned load and approval constraints.
If two quotations propose different capacities, comparing only price per kilowatt may hide whether one design is oversized, undersized, or based on a different roof area.
2. Freeze exact solar modules
Record manufacturer, complete model number, rated power, quantity, cell technology, dimensions, product warranty, performance warranty, and approved or programme requirements where relevant. Replace “Tier 1,” “DCR,” “premium,” or “equivalent” with exact documentation.
3. Freeze the inverter
Record manufacturer, model, AC capacity, phase, system type, MPPT count, voltage and current compatibility, monitoring, environmental rating, warranty, and service process. For hybrid systems, add backup output, supported batteries, operating modes, and critical-load scope.
4. Compare the mounting structure
| Question | Why it matters |
|---|---|
| What material and section? | “Heavy structure” is not a technical specification. |
| What coating or corrosion protection? | Site conditions and long-term exposure matter. |
| What height and layout? | Changes material, wind load, shade, access, and roof use. |
| How is it fixed? | Anchoring, clamping, ballast, and waterproofing have different requirements. |
| What is the design basis? | Wind and structural assumptions should be appropriate to the site. |
5. Itemize electrical protection
Check DC and AC cables, connectors, conduit or tray, DC and AC distribution boxes, isolators, breakers or fuses, surge protection, earthing conductors and pits, lightning protection where required, labels, interconnection cable, and any distribution-board modification. “Complete installation” is not enough.
6. Make services visible
- Site survey and engineering drawings.
- Structural review where required.
- Portal application and technical feasibility follow-up.
- Meter, testing, inspection, and commissioning coordination.
- Transport, lifting, unloading, storage, and site safety.
- Civil foundations, waterproofing, trenching, or restoration.
- Monitoring setup, customer training, and documentation.
7. Separate subsidy from project price
The final quotation should show the full project price according to its GST treatment. A possible subsidy should be shown separately and should not be silently deducted from the amount payable unless the commercial and scheme mechanism genuinely supports that treatment. Government approval and disbursement should not be guaranteed by the installer.
8. Compare taxes and payment terms
Make sure each quote clearly states whether the commercial offer is inclusive or exclusive of GST, its validity, payment milestones, retention if any, cancellation or refund terms, and what triggers each invoice. Compare financing cost separately from equipment price.
9. Read warranty beyond the number of years
- Who receives the complaint?
- Who visits the site and within what service framework?
- Are labour, travel, removal, transport, and reinstallation included?
- Does the manufacturer or installer hold the warranty?
- What maintenance or registration conditions apply?
- What is the process if a model is discontinued?
10. Demand the exclusion list
Typical open items can include roof strengthening, waterproofing, masonry, extra cable beyond an allowance, internet, meter or utility charges, transformer work, crane hire, night work, permits, shutdown support, taxes, or battery backup. An explicit exclusion list protects both customer and installer.
A simple scoring method
Score each bid for design clarity, equipment traceability, structure and safety, scope completeness, approval ownership, commercial clarity, warranty and service, and price. Reject bids with unresolved safety or scope gaps rather than compensating them with a lower number.
Choose the proposal you can understand, verify, operate, and service. If important details exist only in conversation, ask for them in the signed quotation.
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Your Energy's quotation workflow identifies the bill of material, GST type, project scope, subsidy separately, and the final quotation amount.
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