Solar Proposal Warranty Section: What to Include, Sample Wording

You lost a 5 kW deal in Varachha last month and you don't know why. The price was fine. The subsidy math was fine. But the customer's uncle asked one question your proposal could not answer: "Beta, if the inverter dies in year six, who pays?" Your competitor's proposal answered it in four clear lines. Yours said "25 years warranty" and nothing else.

The warranty section is where most Indian solar proposals either win trust or create future legal trouble. Written well, it tells the customer exactly what is covered, for how long, and who to call. Written badly, it makes promises your company will be paying for a decade from now. This guide gives you the structure, the numbers, and copy-paste wording you can use in your next proposal, and it pairs well with our solar proposal best practices checklist for the rest of the document.

The framework we use is the 4-Layer Warranty Stack, explained below. First, let's look at why this section carries so much weight with Indian residential buyers.

Why the warranty section decides whether the customer signs

The warranty section is the trust section. A rooftop solar system is a 25-year asset bought from a company the customer met twice. Your warranty wording is the only written evidence that you will still pick up the phone in year seven.

Residential solar in India runs on PM Surya Ghar Muft Bijli Yojana demand right now. The PM Surya Ghar National Portal crossed 1 crore household registrations within its first two years (MNRE, 2026). Most of these buyers are first-time solar owners. They cannot judge your mounting structure quality, but they can compare two warranty sections side by side.

Notice the gap. The asset lasts 25 years, but no single warranty covers 25 years of everything. Your job in the proposal is to explain the stack honestly, not to hide the gap.

The 4-Layer Warranty Stack

The 4-Layer Warranty Stack is our name for the four separate warranties every rooftop proposal should spell out: module product, module performance, inverter plus balance of system, and your own workmanship cover. Each layer has a different owner, a different duration, and a different claim route.

Most proposals collapse these into one line that says "25 years warranty". That single line is the source of nearly every warranty dispute we see between EPCs and customers. The customer thinks everything is covered for 25 years. You meant only the panel performance. The inverter dies in year six, and now you have an angry WhatsApp forward in the society group.

1. 1

   Module product warranty, from the panel manufacturer

   Covers manufacturing defects like delamination, junction box failure, and frame faults. Typically 12 to 15 years on current Tier-1 TOPCon modules. The claim goes to the manufacturer, usually routed through you.

2. 2

   Module performance warranty, from the panel manufacturer

   Guarantees a minimum output percentage over time, typically 27 to 30 years with 84 to 89 percent of nameplate output at the end. This is the "25-year warranty" customers have heard about, and it only covers panel output, nothing else.

3. 3

   Inverter and balance-of-system warranty, from the equipment makers

   String inverters carry 5 to 10 years, often extendable to 10 or 15 for a fee. Structure, cables, and DC or AC distribution boxes carry their own shorter terms. The inverter is the most failure-prone component, so this layer matters most after year five.

4. 4

   Workmanship warranty, from you, the EPC

   Covers installation quality: roof penetrations, waterproofing, wiring joints, earthing, and structure anchoring. Typically 1 to 5 years. This is the only layer you fully control, and the only one the customer can enforce against you directly.

Write all four layers into every proposal, even if a layer's answer is "not covered by us". An honest gap closes more deals than a vague promise. If you are still building your proposal structure, our guide on how to write a solar proposal shows where the warranty section sits in the full document.

Module warranties: product versus performance

The module section has two warranties, and mixing them up is the most common wording mistake in Indian solar proposals. Product warranty covers defects in the panel itself. Performance warranty covers how much electricity the panel still produces as it ages.

Current Tier-1 TOPCon (Tunnel Oxide Passivated Contact) modules typically carry a 12 to 15 year product warranty and a 27 to 30 year linear performance warranty, guaranteeing roughly 84 to 89 percent of nameplate output at the end of the term (GreenLancer, 2026). Older mono PERC (Passivated Emitter and Rear Cell) modules usually carried 12 years product and 25 years performance.

The degradation line deserves a money translation, because customers understand rupees better than percentages.

When you quote a specific module, pull the warranty years from its actual datasheet, not from memory. Our solar quote contents checklist includes a datasheet field for exactly this reason.

Inverter and balance-of-system warranties

The inverter carries the shortest major warranty in the system and causes the most service calls, so this is the layer your proposal must explain most carefully. String inverters typically carry 5 to 10 years, with paid extensions to 10 or 15 years available from most brands (SolaX Power, 2026).

Microinverters are the exception, often carrying 20 to 25 years because they sit behind each panel. That changes both the price and the warranty section of your proposal, a trade-off we break down in string inverter versus microinverter. For current inverter pricing in India, see our solar inverter price guide.

Three details belong in the inverter warranty lines:

• Exact years and extension cost. Write "5 years standard, extendable to 10 years for ₹X" so the customer can decide at purchase, not at failure.
• Replacement versus repair. A repair-only warranty can mean 30 to 60 days of downtime. A full-replacement warranty bounds the downtime to the service turnaround. State which one applies.
• Who raises the claim. Promise that your office raises and tracks the claim with the brand. That single line converts an abstract warranty into a service.

Balance-of-system items need one honest line each. Structure gets 5 to 10 years against rust-through in most proposals. Cables, earthing, and the lightning arrester usually get 1 to 2 years. If a component has no formal warranty, write that down. Silence reads as cover.

Workmanship warranty: the one layer you own

The workmanship warranty is the only layer written, funded, and enforced entirely by your EPC. It covers installation quality: roof waterproofing, structure anchoring, wiring joints, cable dressing, and earthing pits. Most Indian EPCs offer 1 to 5 years.

This layer is your biggest trust weapon and your biggest liability at the same time. It is the warranty the customer can actually enforce against you, because you cannot point to a manufacturer. A leaky roof penetration in the second monsoon is your cost, full stop.

The practical middle path most Surat EPCs land on: 2 years standard workmanship, extendable to 5 years bundled with an annual maintenance contract (AMC). The AMC fee funds the callback risk. Our solar AMC business model breakdown and AMC pricing guide for India show how to price that bundle so the warranty pays for itself.

Who the customer actually claims against

For every warranty layer, name the party the customer claims against and the party who helps them do it. Confusion here is what turns a routine inverter fault into a negative Google review.

A warranty from an overseas-only entity with no India office is hard to enforce through Indian consumer forums. Prefer brands with an India-registered entity, and say so in your proposal. It is a selling point competitors with grey-market stock cannot copy.

Copy-paste sample wording for your proposal

Here is a plain-English clause block you can adapt. It fits on one proposal page and answers the uncle's question before it is asked. Replace the bracketed fields with your actual datasheet values.

Three wording rules make this clause safe. First, every number traces to a datasheet, never to a sales pitch. Second, exclusions are written next to the cover, not hidden. Third, the claim route names you as the facilitator, which is what the customer is really buying.

This wording also feeds your after-sales motion. A clear warranty makes the year-one service visit an expectation, not a favour, which is the foundation of the retention play in our solar after-sales service guide.

Warranty wording mistakes that create liability

The dangerous warranty mistakes are the ones that sound generous in the sales meeting. Each one below has cost an Indian EPC real money.

Four more patterns to audit in your current template:

• "25 years warranty" as one line. It merges four different warranties into a promise no manufacturer backs. Write the four layers with their real years instead.
• Copying the datasheet's marketing line. Datasheets say "up to 30-year performance warranty". Your proposal must say what the guarantee actually pays, repair, replacement, or prorated credit.
• No exclusions listed. If the proposal does not exclude lightning and storm damage, the customer assumes it is covered. Write exclusions plainly.
• Promising generation, not performance. The performance warranty covers panel output under test conditions, not the units on the customer's bill. Say "the manufacturer warrants module output", never "we guarantee 1,500 units per kW".

The fix for all four is the same: quote the datasheet, name the claim route, and put exclusions in writing. Boring wording is safe wording.

How QuickEstimate fits

QuickEstimate builds the warranty section into your proposal template once, so every quote your sales boys send from the field carries the same safe wording. You update the datasheet numbers in one place, and the next 60-second PDF reflects them, in English, Hindi, or Gujarati.

• Proposal Generator, branded PDF with a standardised warranty section, subsidy math, and your terms pre-filled.
• Quotation System, keep module and inverter datasheet values current across the whole team's quotes.
• WhatsApp Follow-up, deliver the proposal on WhatsApp and keep the warranty conversation on record against the lead.
• Pipeline Management, see which proposals are pending and which customers asked warranty questions, so nothing slips.

The result: every customer gets the same defensible warranty wording, whether your senior engineer or your newest sales trainee sent the quote.

What to do this week

You can fix your warranty section in the next seven days without touching pricing.

1. Pull the datasheets for your two most-quoted modules and one inverter. Write down the exact product warranty years, performance warranty years, and end-of-term output percentage. Replace every "25 years warranty" line in your template with these four-layer numbers today.
2. Paste the sample clause from this post into your proposal template and fill the brackets. Get your senior installer to check the workmanship exclusions against the failures you have actually repaired in the last two monsoons.
3. Send one test proposal to your own number (the QuickEstimate demo takes two minutes to set up) and read the warranty section like a customer's uncle would. If any line promises something you cannot fund, rewrite it before the next site visit.

Frequently asked questions

What should a solar proposal warranty section include?

It should include four layers with exact years for each: module product warranty (typically 12 to 15 years on TOPCon panels), module performance warranty (27 to 30 years), inverter warranty (5 to 10 years, extendable), and your own workmanship warranty (1 to 5 years). For each layer, state what is covered, what is excluded, and who the customer claims against. One line on how to raise a claim, ideally through your office, completes the section.

What is the difference between product warranty and performance warranty on solar panels?

Product warranty covers physical and manufacturing defects in the panel, such as delamination, junction box failure, or frame faults. Performance warranty guarantees the panel still produces a minimum percentage of its rated output as it ages, typically 84 to 89 percent at year 27 to 30 on current TOPCon modules. Both come from the manufacturer, but they are claimed differently: performance claims need generation data as proof.

How long is a solar inverter warranty in India?

Most string inverters sold in India carry a 5-year standard warranty, extendable to 10 years for a fee, according to brand datasheets compiled by SolaX Power in 2026. Some Indian brands offer 10 to 12 years as standard. Entry-level brands may offer only 1 to 2 years. Microinverters are the exception, often carrying 20 to 25 years. Always quote the exact brand and model warranty from the current datasheet in your proposal.

Should an EPC offer its own workmanship warranty?

Yes, because it is the only warranty layer the customer can enforce directly against you, and it differentiates you from competitors. Most Indian EPCs offer 1 to 5 years covering roof penetrations, structure anchoring, wiring, and earthing. The safe structure is 2 years standard, extendable to 5 years when bundled with a paid annual maintenance contract, so the AMC fee funds your callback risk.

Can I write "25-year warranty" in my solar proposal?

No, not as a single blanket line. No manufacturer warranties the whole system for 25 years. The 25 to 30 year figure applies only to module performance. The inverter typically carries 5 to 10 years, and your workmanship cover is 1 to 5 years. Writing "25 years warranty" merges these into a promise you cannot honour, and verbal or WhatsApp repetitions of it can be used as evidence against you under the Consumer Protection Act, 2019.

Who does the customer claim against if a solar panel fails?

The claim goes to the panel manufacturer, but the customer should never have to pursue it alone. Best practice is for your EPC office to raise and track the claim using the invoice, serial numbers, and installation photos you kept on file. State this claim route in the proposal. Choosing ALMM-listed brands with an India-registered entity makes claims far easier to enforce through Indian consumer forums.

Does the PM Surya Ghar subsidy affect warranties?

Indirectly, yes. PM Surya Ghar requires ALMM-listed modules and, under current rules, listed inverters for subsidy eligibility, which pushes you toward brands with documented, enforceable warranties in India. The subsidy itself, ₹30,000 per kW for the first 2 kW plus ₹18,000 for the third kW, capped at ₹78,000 (MNRE, 2024 guidelines), does not change warranty terms. It does raise the stakes on paperwork, because subsidy claims need the same invoices and serial numbers warranty claims need.

What exclusions should a solar workmanship warranty list?

List these plainly: damage from alterations or repairs by third parties, civil or waterproofing work done by others after installation, storm and lightning damage beyond rated protection, animal damage, and neglect of basic cleaning. Also exclude generation shortfalls caused by new shading, such as a neighbour's new construction. Clear exclusions protect you without weakening the promise, because what remains covered is stated just as clearly.