How to read a solar quote

Before you get quotes: know your baseline

• Calculate your average monthly consumption (units/kWh) from the last 12 bills
• Note your peak consumption month and the tariff slab you are in
• Measure your available roof space (approx. sq. ft.) and check orientation, south-facing is ideal
• Confirm with your housing society or local authority that rooftop solar is permitted
• Check your DISCOM website for net-metering eligibility and the application process

The 12-point checklist

1. System size and expected generation

The quote must specify system size in kW and expected annual generation in kWh. Use the rule of thumb: 1 kW of solar generates 1,300–1,500 kWh/year in most Indian cities. If the quote promises significantly more, ask for the calculation basis.

2. Panel brand, model, and efficiency

Check the panel manufacturer and model number. Efficiency should be clearly stated, 18–22% for good-quality mono-PERC panels. Look up the datasheet and verify the specs independently. Avoid quotes that say only "Tier 1 panels" without naming the brand and model.

3. Inverter brand and type

The inverter converts solar DC to AC and is the most failure-prone component. Insist on named brands: SolarEdge, Fronius, SMA, ABB, Delta, Growatt or similar. Avoid "generic Chinese inverter" or unnamed brands. String inverters are standard; microinverters cost more but perform better in partial shade.

4. Warranty terms, panel, inverter, workmanship

• Panels: 25-year performance warranty (80% output at year 25) is standard; 10-year product warranty is standard
• Inverter: 5-year warranty is standard; 10-year extended is available from good brands
• Workmanship / installation: 2–5 years is standard. Ask who backs it, the brand or the installer?
• Red flag: any quote with less than a 10-year panel performance warranty or less than a 5-year inverter warranty

5. MNRE empanelment of the installer

For the PM Surya Ghar subsidy, the installer must be empanelled with MNRE. Ask for their vendor registration number and verify it on the National Portal for Rooftop Solar (pmsuryaghar.gov.in). Using a non-empanelled installer means you lose the subsidy, up to ₹78,000.

6. Net-metering application support

Will the installer handle the net-metering application with your DISCOM? Some charge extra. Net metering can take 30–90 days in most states, confirm the timeline and who is responsible.

7. Generation guarantee

Some installers offer a generation guarantee, committing to a minimum annual kWh output. This is a strong signal of confidence. If actual generation falls below the guaranteed level, they compensate. Ask if it is included.

8. Breakdown of costs

A good quote itemises panel cost, inverter cost, mounting structure, wiring, labour, net-meter cost, and AMC. Avoid lump-sum quotes with no breakdown, they make it impossible to compare vendors fairly.

9. Annual Maintenance Contract (AMC) terms

Post-installation maintenance includes panel cleaning, inverter health checks, and cable inspection. Confirm whether AMC is included, for how many years, and the annual cost after the included period.

10. Subsidy handling

Confirm in writing: does the quoted price include or exclude the subsidy? Who applies, you or the installer? When is it credited? Some installers quote a "subsidy-adjusted" price and pocket the difference if the subsidy is delayed. Always understand the subsidy cash flow.

11. Timeline and milestones

A complete installation, panels, inverter, wiring, net-meter application, typically takes 10–21 days for residential systems. Get a written timeline with milestones. Delays beyond 45 days should trigger a penalty clause.

12. References and review verification

Ask for three references from the installer's existing customers in your city, and call them. Check Google reviews and any complaints on consumer forums. A credible installer will have verifiable reviews and willing references.