The exact questions that separate reliable solar installers from ones you’ll regret including what a good answer actually sounds like.
Going solar is a 25-year commitment. The company you choose will determine your actual savings, your subsidy outcome, how long your net meter takes, and whether anyone picks up the phone years from now when you need support.
Most homeowners know they should “ask questions” before signing. But nobody tells you what a good answer sounds like versus a red flag. That’s what this guide does.
Here are the questions to ask and exactly what to listen for when they answer.
Before You Even Call Anyone: Questions to Ask Yourself
These three questions shape everything that follows. Know the answers before your first site visit.
- What is my average monthly electricity consumption (in units)?
Check your last 3–6 DISCOM bills and note the average units consumed per month. This is the single most important number for sizing your system correctly. Installers who quote without asking this question first are guessing, not designing. - What is my monthly electricity bill, and which consumption slab am I in?
Your DISCOM tariff slab determines your per-unit cost and therefore your savings per unit of solar generation. A household paying ₹8–10/unit in the top slab saves far more per kW of solar than one paying ₹3–4/unit in subsidised lower slabs. - Do I own my roof, and how old is it?
Solar panels last 25+ years. Installing them on a roof that needs replacement in 5 years means expensive panel removal and reinstallation. Know your roof condition before any salesperson arrives.
Questions About the Company
1. Are you MNRE-empanelled, and can you show me the certificate?
Why it matters: Only MNRE-empanelled installers can process the PM Surya Ghar Muft Bijli Yojana subsidy on your behalf. Without this, your panels go up but your subsidy application cannot be filed and you receive ₹0 from the government scheme.
Good answer: “Yes, here is our MNRE empanelment certificate. You can also verify our name on pmsuryaghar.gov.in.” They show it immediately.
Red flag: Any hesitation, “we’re in the process of getting it,” or “the subsidy doesn’t matter for your case” without a clear reason why.
Also ask: State nodal agency registration (TSREDCO in Telangana, KSEB in Kerala, TEDA in Tamil Nadu). This is needed for net meter commissioning.
2. How long have you been operating, and do you have local references?
Why it matters: India’s solar boom has brought in many new operators. Experience matters for managing DISCOM paperwork, handling installation edge cases, and providing genuine after-sales support.
Good answer: A specific number of years, with references from at least two installations in your locality or city. Ask if you can speak to those customers directly not just see photos.
Red flag: “We’re relatively new but our team has experience” or references only from distant locations.
3. Does your installation team work in-house, or do you subcontract?
Why it matters: Many solar companies especially larger ones sell the project and hand installation to third-party contractors. This creates accountability gaps: if something goes wrong, neither party takes ownership.
Good answer: “Our installation team is in-house and employed directly by us.” If they do use subcontractors for specific tasks (like roofing or electrical connection), they should name who and explain their quality oversight process.
Red flag: Vague answers, or confirmation that the full installation is outsourced to whoever is available.
Questions About the Equipment
4. Are all panels and inverters on the ALMM list? Can you share the model numbers?
Why it matters: The ALMM (Approved List of Models and Manufacturers) is MNRE’s register of certified components. If even one component is off the ALMM list, your PM Surya Ghar subsidy application will be rejected even if the installer is empanelled.
Good answer: “Yes, here are the exact model numbers for the panels and inverter. You can verify them on the MNRE ALMM portal.” Takes 5 minutes to check yourself.
Red flag: “All our panels are certified, don’t worry” without providing model numbers. Or any resistance to sharing specific component details before you sign.
Trusted Indian panel brands currently on ALMM: Waaree, Tata Power Solar, Adani Solar, Vikram Solar, Renewsys. For inverters: Sungrow, Delta, Growatt, Havells.
5. What is the panel efficiency, and is it monocrystalline or TOPCon?
Why it matters: Panel efficiency determines how much electricity you generate per square foot of roof space. This matters most when roof space is limited.
Good answer: A specific efficiency percentage. Standard monocrystalline panels run 19–21% efficiency. TOPCon panels (the newer standard) run 21–23% and perform better in high-heat conditions common across South India.
What to know: Polycrystalline panels are older technology and generally less efficient per square metre. Most quality installers now use monocrystalline or TOPCon by default.
6. Does the inverter have real-time monitoring, and can I see a demo?
Why it matters: Real-time monitoring lets you detect underperformance early within days, not months. Without it, shading issues, equipment faults, or dust-related losses can silently reduce your output for extended periods.
Good answer: Yes and they show you a live dashboard from an existing installation so you know what you’re getting.
Red flag: Monitoring offered only as a paid add-on, or vague answers about “you’ll get reports.” Monitoring should be standard, not an upgrade.
7. What are the five warranties and who backs each one?
This is the question most homeowners don’t know to ask. A complete solar installation carries five distinct warranties:
| Warranty Type | What It Covers | What to Expect |
| Panel performance | Guaranteed output over time (minimum 80% at year 25) | 25 years minimum Tier 1 brands now offer 30 |
| Panel product | Manufacturing defects, physical failure | 10–12 years from manufacturer |
| Inverter | Equipment failure and replacement | 5–10 years; check local service presence |
| Mounting structure | Frame corrosion, structural failure | 10 years minimum |
| Workmanship | Quality of installation wiring, sealing, waterproofing | 5 years minimum, from the installer |
Good answer: All five provided separately, in writing, with the warranty provider’s name on each. Not a single combined letter.
Red flag: “Our panels come with a 25-year warranty” meaning they’ve told you about one warranty and implied that covers everything.
Questions About Cost and Subsidy
8. What is the full cost broken down by component?
Why it matters: Solar quotes vary enormously in what they include. A quote missing key items isn’t actually cheaper it’s incomplete.
A complete quote should include:
- Panels (brand, model, wattage)
- Inverter (brand, model)
- Mounting structure (type, material)
- DC and AC cabling
- Earthing and lightning protection
- Net meter application fee
- DISCOM coordination and approval
- Subsidy filing support
- Monitoring system setup
Good answer: A written, itemised proposal with all the above. No verbal-only quotes.
Red flag: Any of the above listed as “extra” or a quote given before a proper site visit.
2026 indicative market rates (Tamil Nadu / South India):
| System Size | Before Subsidy | After PM Surya Ghar Subsidy |
| 1 kW | ₹75,000 – ₹85,000 | ₹45,000 – ₹55,000 |
| 3 kW | ₹1,89,000 – ₹2,15,000 | ₹1,11,000 – ₹1,37,000 |
| 5 kW | ₹2,50,000 – ₹2,90,000 | ₹1,72,000 – ₹2,12,000 |
A quote significantly below these ranges needs explanation. Ask exactly which component has been priced lower and why.
9. What subsidy do I qualify for, and do you handle the full application?
Why it matters: Many installers say they “handle the subsidy” but in practice submit incomplete applications or stop following up after installation. The subsidy is credited to your bank account but only after correct filing, DISCOM commissioning, and MNRE portal verification.
PM Surya Ghar 2026 subsidy entitlements:
| Monthly Consumption | System Size | Central Subsidy |
| Up to 150 units | 1–2 kW | ₹30,000 – ₹60,000 |
| 150–300 units | 2–3 kW | ₹60,000 – ₹78,000 |
| Above 300 units | 3 kW+ | Fixed ₹78,000 |
Good answer: They confirm the exact subsidy amount for your consumption level, confirm they file through the national portal, and explain the typical disbursement timeline in your state.
Red flag: Subsidy amount that exceeds the above figures for a standard residential system. ₹78,000 is the maximum central subsidy any claim significantly higher without explaining state top-ups is false.
10. What is my expected payback period show me the calculation?
Why it matters: Any installer can say “3 years.” The right answer is a written savings projection showing your system size, expected monthly generation in units, the specific tariff slab you’re in, and resulting monthly bill saving.
Good answer: A site-specific generation estimate using your location’s irradiance data — not a national average. For most of South India, a 5 kW system generates 650–720 units/month, saving ₹4,000–₹6,000/month depending on your tariff slab. Payback: 3.5–5 years after subsidy.
Red flag: A generic “your payback is X years” without showing the underlying calculation. Unverifiable claims are meaningless.
Questions About Installation and Process
11. Have you done a proper site survey shading analysis, roof load, sanctioned load?
Why it matters: A competent installer will check all three before recommending a system size. Skipping this means a system that underperforms from Day 1.
Shading analysis – Even a water tank, parapet wall, or nearby tree casting shadow during peak hours can reduce output by 20–40%. Ask for a shadow analysis report.
Roof load capacity – A 3 kW system adds 150–200 kg to your roof. Older structures or roofs with existing cracks need structural clearance first.
Sanctioned load check – Your solar system capacity generally cannot exceed your DISCOM sanctioned load. If your sanctioned load is 3 kW, a 5 kW system application for net metering will be rejected. A thorough installer checks this at the survey stage.
Good answer: All three checked and documented before the proposal is finalised.
Red flag: A quote issued the same day as a 15-minute roof visit or a quote issued before any site visit at all.
12. Do you handle the net meter application end-to-end?
Why it matters: Net metering allows you to export surplus generation to the DISCOM grid and receive bill credits. Without it, your system runs but you get no credit for excess units. The application involves technical feasibility approval, meter replacement by DISCOM, and final commissioning a process that takes 3–8 weeks depending on your state.
Good answer: “Yes, we manage the full application from feasibility submission to DISCOM inspection coordination to commissioning. We give you a realistic timeline for your specific DISCOM.”
Red flag: “You’ll need to follow up with the DISCOM yourself” or vague timelines with no commitment to manage the process.
13. Will installation require any on-site welding on my roof?
Why it matters: Professional solar mounting uses pre-fabricated structures bolted to the roof, no welding required. On-site welding is a sign of non-standard practice and creates genuine risk of roof damage and waterproofing failure.
Good answer: “No, we use pre-fabricated mounting structures. No welding on your roof.”
Red flag: Any mention of on-site welding or cutting on the roof surface.
Questions About After-Sales and Long-Term Support
14. What is your Annual Maintenance Contract (AMC) and what does it cover?
Why it matters: Dust accumulation alone reduces solar output by 5–15% in many parts of India, particularly during summer. A properly priced AMC covering scheduled cleaning, annual inspection, inverter health checks, and minor repairs pays for itself in preserved generation.
Good answer: A written AMC with defined scope, visit frequency, and response time for unscheduled issues. Should be available as an optional add-on at the time of installation.
Red flag: “You don’t need maintenance solar is maintenance-free.” It isn’t. This is a closing tactic, not a fact.
15. What happens if my system underperforms against your stated output estimate?
Why it matters: Monitoring data may show your system generating 15–20% less than projected. You need to know the installer’s accountability process before this happens not after.
Good answer: “We provide a generation estimate with a tolerance range. If actual performance falls below it without a clear reason (weather, shading change), we investigate and remedy under workmanship warranty.” Get this in writing.
Red flag: “Solar generation varies, we can’t guarantee output.” True in principle, but a quality installer should stand behind their design estimate within a reasonable range
Red Flags – Walk Away If You See These
- Urgency pressure. “This price is only valid today” or “subsidy slots are filling fast” are sales tactics, not real constraints. Quality installers don’t use countdowns to close deals.
- Quote before site visit. Any price given without a proper roof assessment, load analysis, and shading check is fabricated. You cannot correctly size a solar system remotely.
- No written proposal before advance payment. Never pay a booking advance without a signed document showing: system size, panel and inverter brand names and model numbers, complete cost breakdown, warranty terms, and installation timeline. A verbal quote is not a contract.
- Inflated subsidy promises. The PM Surya Ghar maximum residential central subsidy is ₹78,000. Any claim significantly higher without explaining state-level additions is false and a sign the company is willing to mislead you on other things too.
- No fixed office address. If a company has no verifiable physical presence only WhatsApp contact and referrals you may not be able to reach them for service, warranty claims, or complaints. Verify the address on their GST registration certificate.
- Extreme price gap. A quote 30–40% below market almost always means off-ALMM components (subsidy lost), undersized wiring (fire risk), or a company that will disappear post-installation. Compare specifications, not just totals.
Your Pre-Signing Checklist
Use this before committing to any installer:
- [ ] Company physical address verified on GST certificate
- [ ] MNRE empanelment verified on pmsuryaghar.gov.in
- [ ] State nodal agency registration confirmed
- [ ] Panel and inverter model numbers confirmed ALMM-listed
- [ ] Written proposal received with all component specs and full cost breakdown
- [ ] All five warranties documented separately in writing
- [ ] Site survey completed shading, roof load, sanctioned load all checked
- [ ] Net meter application confirmed as included in scope
- [ ] Subsidy filing confirmed as part of service
- [ ] No on-site welding pre-fabricated mounting structure confirmed
- [ ] Installation team in-house (not fully subcontracted)
- [ ] Real-time monitoring included and demonstrated
- [ ] AMC terms available in writing
- [ ] At least two local references provided and contacted