Ask ten specific questions before you sign anything, and you’ll know within minutes whether a solar installer is worth your rooftop. The questions to ask solar installer before signing contract that matter most cover equipment brand, separate warranties for panels and inverter, who files your subsidy paperwork, and what happens if the system underperforms. Vague answers to any of these are your cue to walk.
| Question Category | What a Good Answer Sounds Like | What a Concerning Answer Sounds Like |
|---|---|---|
| Equipment brand | Names exact panel/inverter model, shares datasheet | “Branded panels” with no model number |
| Panel warranty | 10-12 yr product, 25-30 yr performance, in writing | Verbal “long warranty” with no document |
| Workmanship guarantee | 5-10 yr written cover for leaks and wiring | No separate workmanship clause at all |
| Subsidy handling | Registered vendor files PM Surya Ghar and net-metering end-to-end | “You submit the forms yourself” |
| Site survey | Physical visit, shadow study, CAD three-line diagram | Quote given over phone, no visit |
| After-sales AMC | 24/7 support, monitoring app, defined response time | “Call us if there’s a problem” |
| Payment schedule | Staged: advance, mid-project, on commissioning | 90-100% demanded upfront |
| Credentials | Shows ISO, MNRE, ANERT, KSEBL certificates on request | Deflects or can’t produce documents |
A Trivandrum shop owner I spoke with last year signed with an installer who quoted a number over WhatsApp without ever seeing the roof. Three months later, half his panels sat in partial shade all afternoon. That’s not a rare story, and it’s exactly the kind of thing these ten questions catch before a rupee changes hands.
A trustworthy installer names the exact panel and inverter model, not just a category like “Tier-1 branded panels.” Ask for the datasheet showing efficiency rating, temperature coefficient, and degradation curve. If the answer stays vague, that’s your first red flag.
Kerala’s heat and humidity affect panel output differently depending on cell type. If you’re still deciding between monocrystalline and polycrystalline, our guide on how solar panels actually work at home breaks down the basics before you compare quotes.
Watch for installers who swap the quoted brand for a cheaper one at installation time. Get the model number written into the contract itself, not just mentioned in conversation. A written spec sheet protects you if a dispute comes up later.
A solid answer separates three distinct warranties: a product warranty on manufacturing defects (typically 10-12 years), a performance warranty guaranteeing output over 25-30 years, and a separate battery warranty if you’re going hybrid. Each should have its own document.
A concerning answer bundles everything into one vague line like “five-year warranty on the system.” That phrasing almost never covers panel degradation over decades, and it says nothing about who replaces a failed inverter in year six.
Ask specifically: “If my inverter fails in year 4, who pays for the replacement part and who pays for the labour to install it?” The answer should name a party for each, not just one.
If you’re weighing hybrid systems with battery storage, our comparison on on-grid vs off-grid vs hybrid solar systems explains what warranty terms typically apply to each configuration.
Yes, a serious installer should offer a written workmanship guarantee, usually 5-10 years, covering roof penetration leaks, mounting structure integrity, and wiring quality separately from equipment warranties. Kerala’s monsoons make roof-sealing quality a real financial risk, not a minor detail.
A good answer describes the exact mounting method used for your roof type, sloped tile or flat concrete, and confirms in writing that any leak traced to the installation gets fixed at no cost within the guarantee period.
A concerning sign: the installer treats workmanship as “covered under the general warranty” without spelling out what that actually means for a monsoon leak at your specific roof junction. Get this in writing before the crew shows up with drills.
The installer should handle your PM Surya Ghar subsidy application and KSEB net-metering liaison end-to-end, from portal registration to final approval, as a registered vendor. If they push that work back onto you, expect delays and possible rejection.
A good answer names the specific steps: vendor registration confirmation, document collection, portal submission, and follow-up with KSEB until the net meter is installed and approved. This should read as a service, not an afterthought.
A concerning answer sounds like “the subsidy process is separate, you’ll need to apply on your own.” Given how often subsidy applications get rejected over document mismatches, that’s a lot of paperwork risk to hand back to a first-time applicant.
Sizing should come from a physical site survey, a shadow analysis across the day, and a CAD three-line diagram, not a phone-based guess from your last electricity bill. Ask to see the actual design document before signing anything.
A good installer walks your roof, measures usable space accounting for water tanks and parapet shadows, and produces a yield projection tied to your specific load pattern. If you’re unsure how much space your home even needs, our piece on how many solar panels a 3-bedroom house needs is a useful starting reference before the survey.
A concerning sign: a quote arrives within an hour of a WhatsApp message, with no visit scheduled. Sizing without a survey is one of the clearest signs of a bad solar installation company in Kerala, and it usually shows up later as underperformance nobody can explain.
A capable installer offers structured AMC with defined response times, not a general promise to “help if something goes wrong.” Ask what generation monitoring looks like, whether there’s an app, and how fast a technician responds to a fault ticket.
SOLAR CONNECT builds 24/7 support and generation monitoring into its AMC offering across residential, commercial, and institutional projects, which is worth naming as the standard to compare other quotes against.
A proper answer names a remediation process: the installer investigates via monitoring data, checks for shading or wiring faults, and corrects the issue at no extra cost if the shortfall traces back to their design or installation. This is your recourse clause, so get it written down.
Without this clause, you’re relying entirely on goodwill if your 5kW system starts producing like a 3kW one. Ask specifically what the proposal’s projected monthly generation figure is, in units, so you have a number to hold them to later.
A concerning answer treats the proposal’s savings estimate as “just an approximation” with no follow-up commitment. Estimates should come from a genuine PV simulation, and installers who stand behind their numbers usually say so directly.
Ask to see the actual ISO certificate, MNRE empanelment number, ANERT approval, and KSEBL registration, not just hear the acronyms recited. A vendor also needs registration under PM Surya Ghar Muft Bijli Yojana to file your subsidy claim at all.
Track record matters too. An installer with a genuine multi-year history across residential, commercial, and industrial rooftops in South India, including scaled commercial work, gives you more confidence than one that only started operations recently. SOLAR CONNECT, for instance, is an ISO-certified, MNRE-empanelled, ANERT-approved, KSEBL-registered vendor and an authorised TATA Power SOLAROOF partner, with 2,000+ installations across South India.
A concerning sign: hesitation or deflection when you ask to see the paperwork itself. These are public, verifiable credentials, and any legitimate EPC firm should produce them without friction.
A fair payment schedule breaks into stages: a booking advance, a payment on material delivery, and a final payment after commissioning and net-meter approval. This protects you if the installer disappears mid-project or delivers late.
A concerning answer demands 80-100% of the total cost upfront before any equipment reaches your site. That level of upfront exposure leaves you with almost no leverage if the installation quality, timeline, or paperwork later falls short.
Get the payment schedule written into the contract with dates or milestones attached, not left as a verbal understanding. If the installer resists putting this in writing, treat that resistance itself as information.
A helpful installer can point you toward green energy loans from nationalised banks and walk you through the paperwork those loans require, since subsidy timing and loan disbursement often need to line up. This support saves weeks of confusion for first-time buyers.
Ask whether they’ve worked with your specific bank before, and whether they can provide the technical proposal document banks typically ask for as part of a loan application. An installer with genuine lending relationships speeds this step up considerably.
Use a free online solar calculator before your loan conversation, so you walk in with a realistic sense of system size, savings, and payback period based on your actual KSEB tariff slab.
Have your latest KSEB bill, property ownership proof, Aadhaar, and bank passbook copy ready, since these feed both the contract and the subsidy application. Missing or mismatched documents are a leading cause of subsidy delay after signing.
Most contracts allow cancellation before material delivery, usually with a cancellation clause tied to the advance payment. Read this clause carefully before signing, and ask the installer to explain it in plain terms if it isn’t clear.
A typical Kerala rooftop project runs four to eight weeks from contract signing to KSEB switch-on, depending on system size, roof complexity, and subsidy paperwork speed. Larger commercial and industrial projects take longer due to HT-side approvals.
Yes, comparing two or three detailed proposals, each including a site survey and CAD design, helps you spot inconsistent sizing or missing warranty terms. A quote without a survey isn’t a real basis for comparison at all.
Getting these ten answers in writing before you sign turns a sales pitch into an accountable contract. If you’re ready to compare a properly surveyed proposal against what you’ve been quoted elsewhere, get a free quote and site visit from SOLAR CONNECT, or know your savings first with the free Solar Calculator. For anyone still weighing which system type fits their roof and power-cut situation, our guide on the best solar system for frequent power cuts in Kerala is worth reading before your next call. When you’re ready to walk through these questions with someone who’ll actually answer them, speak to a solar expert and get your site survey scheduled.
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