Solar Warranty Questions to Ask Before Signing: 2026 Indonesia

You're putting Rp 80 to 300 million on your roof. The system is supposed to run reliably for 25 years. And yet, most homeowners in Indonesia spend more time vetting a contractor for a bathroom tile job than asking warranty questions on a solar install. That's a mistake worth correcting before you sign anything.

Indonesia's solar warranty structure is more layered than most buyers realize, and the weakest link is rarely the panels or the inverter itself. It's the installer's business continuity, the parts availability behind the warranty promise, and a few exclusions buried in the workmanship clause. This guide gives you 12 questions to ask, in order, before any ink dries.

Reading this in Bahasa Indonesia? Switch to: /blog/garansi-workmanship-vs-garansi-produk

TL;DR

• Solar systems have 4 separate warranty layers: panels (25 yr), inverter (5-10 yr), battery (5-10 yr or 6,000+ cycles), and workmanship (1-5 yr from the installer). Each has different owners and claim paths.
• Get all four layers in writing in the signed contract. A warranty promised over WhatsApp doesn't exist when you actually need it.
• Roof penetration waterproofing is excluded by many Indonesian installers by default. Confirm it's explicitly covered in the workmanship clause before signing.
• Replacement parts availability matters as much as warranty terms. A 10-year warranty backed by local distributor stock beats a 12-year warranty where you wait months for a factory China shipment.
• PT-registered installers with a 10-year track record are far safer than CV or perorangan operators, who close at 30 to 50% rates within 5 years in Indonesia.
• The questions most buyers skip: battery state-of-health certification, installer legal entity type, what firmware changes void inverter coverage, and who handles claims if the installer closes.

The four warranty layers you're actually buying

Before the 12 questions, a quick map. Every residential solar system in Indonesia has at least 4 warranty layers, each from a different party:

Panel manufacturer warranty (from the panel brand, not the installer): Two sub-types. Linear power warranty: 25 years, guaranteeing at least 80 to 87.5% of rated output by year 25. Product defect warranty: 12 to 15 years for physical failures, cracking, or delamination. Tier-1 brands like Jinko, LONGi, Canadian Solar, and Trina all offer both. The claim path runs through the brand's authorized Indonesia distributor.

Inverter manufacturer warranty (from the inverter brand): 5 years is the standard. Quality brands (Deye, Sungrow, Huawei, Growatt, Luxpower, Solis) offer 10-year extensions for an extra Rp 2 to 5 million. Inverters are the most failure-prone component in years 6 to 12, so the extension often makes sense.

Battery manufacturer warranty (from the battery brand): Typically 5 to 10 years, or a cycle count (6,000 cycles minimum for LiFePO4), whichever comes first. Pylontech, BYD, and HinaESS all provide both metrics. At one cycle per day, 6,000 cycles is roughly 16 years of real-world use.

Workmanship warranty (from the installer): Covers what the installer physically did: roof mounts, cabling runs, roof penetration sealing, wiring connections, commissioning. Duration ranges from 1 to 5 years. This is entirely separate from manufacturer warranties and only covers installation defects, not product failures.

Questions 1 to 4: the manufacturer layer

Q1. What's the panel linear power warranty and degradation guarantee?

You want 25 years to at least 80% retention, ideally 84.8 to 87.5% for modern N-type panels (JinKO Tiger Neo, Trina Vertex S, LONGi Hi-MO 6). Ask for the warranty certificate PDF from the brand, not just the installer's word. A single-page document from Jinko or Trina listing the exact degradation curve year by year is standard on any Tier-1 quote.

Q2. What's the panel product warranty, and who handles claims in Indonesia?

Standard is 12 to 15 years. More important: ask for the name and address of the brand's authorized Indonesia distributor. If an installer can't give you a company name and a contact number, they're not buying from the authorized channel, and your 25-year power warranty has no real enforcement path.

Q3. What's the inverter warranty, and is a 10-year extension available?

5 years standard from the brand. If the brand offers a 10-year extension, ask for the cost. Given that a 5 kW hybrid inverter replacement costs Rp 18 to 28 million, an extension at Rp 3 million is straightforward math. Confirm the extension is underwritten by the manufacturer or a named distributor, not just promised verbally by the installer.

Q4. What's the battery warranty in years and in cycles?

Both numbers matter. "5-year warranty" means nothing if the cycle warranty is only 2,000 cycles, which is about 3 years at one cycle per day. You want: 5 to 10 years OR 6,000+ cycles, whichever comes first. Pylontech US3000C: 10 years, 6,000 cycles. BYD B-Box Premium: 10 years, 6,000 cycles. HinaESS PowerGem Plus: 5 to 10 years depending on the model. Ask to see the written spec sheet, not the marketing brochure.

Questions 5 to 8: the installation layer

Q5. What exactly does your workmanship warranty cover?

The phrase "workmanship warranty" means different things to different installers. Push for specifics: mounting bracket integrity, DC and AC cable runs and terminations, roof penetration waterproofing (more on this below), breaker and fuse installation, and commissioning calibration. Ask them to list what's excluded. Common exclusions: normal wear, acts of nature, and "damage from third-party modification." Make sure the scope is written into the contract, not floating in a chat message.

Q6. Is there a free check-up included in year 1?

Reputable installers include a 12-month post-commissioning check-up at no charge: visual inspection, connection torque recheck, production comparison against the commissioning baseline, and battery state review. If an installer declines to include this, treat it as a flag. It costs them very little (they're coming anyway if there's a callback issue) and signals how they approach long-term customer relationships.

Q7. Where do replacement parts come from, and what's the lead time under warranty?

This separates installers with real service capacity from those who'll string you along for months while they "contact the distributor." Ask directly: if a 5 kW Deye inverter under warranty needs replacing, how long does it take? A good answer is 2 to 5 business days from local stock. A vague answer like "we'll check with our supplier" is a warning. Before you sign, verify that your inverter brand's Indonesia distributor actually stocks replacement units locally.

Q8. What's the final payment trigger?

Tie the final payment to the handover acceptance sign-off, not to "when installation is complete" or "when we test it next week." In Indonesian practice, this document is called BAST (Berita Acara Serah Terima), but plain English "commissioning sign-off" works fine in the contract. The moment the final payment is made, the installer's motivation to address post-install issues drops sharply. Make them earn the last 30 to 50% by delivering a working, commissioned system you've personally verified runs correctly.

Questions 9 to 12: the ones most buyers skip

Q9. Does the workmanship warranty specifically cover roof leaks from panel penetrations?

This is the most common hidden exclusion in Indonesian solar contracts. Many installers write clauses covering "installation defects" but explicitly exclude "consequential damage" or "roof penetration waterproofing." Roof leaks from bad mounting seals are the most damaging long-term failure mode in older Bali tile roofs and Jakarta townhouses. Confirm this is named and covered in the workmanship warranty clause before you sign.

Q10. What voids each warranty layer?

Get this in writing, per layer. Common voiders: panels (physical damage, installation outside OEM specs, unauthorized modification); inverter (DIY wiring modifications, unauthorized firmware updates from a third party, adding non-OEM batteries to the system); battery (third-party BMS, charging outside spec voltage, sustained ambient above 50C); workmanship (modification by another installer after the original install, replacement with non-approved parts). Know these before you DIY anything at year 3.

Q11. Is there a battery state-of-health certification at year 5 and year 10?

Some premium battery brands (BYD and Pylontech Force series) provide a state-of-health report at mid-warranty intervals, confirming the battery is degrading within spec. This is a nice-to-have that signals the brand takes long-term performance seriously. If the installer doesn't mention it, ask whether the brand offers it. Request it be scheduled as part of the project handover documentation.

Q12. What's your company's legal entity, and how long have you operated?

This feels like a bureaucratic question, but it's arguably the most important of all 12. Small CV (Commanditaire Vennootschap) and perorangan (sole proprietor) installers in Indonesia have a 30 to 50% closure rate within 5 years. If your installer closes in year 4, your workmanship warranty is unenforceable. PT status with at least 5 to 10 years of documented track record is the meaningful bar. Ask for the company's NIB (Nomor Induk Berusaha) business registration number and verify it via the OSS portal.

When these questions won't fully protect you

Asking the right questions reduces risk significantly, but it doesn't eliminate it. A few honest caveats worth stating up front.

At the lower end of the market (Rp 40 to 60 million systems from small local crews), the probability of getting a complete, properly documented warranty package is lower. Chasing enforcement on a Rp 1.5 million workmanship claim in year 4 rarely makes financial sense when the installer has closed. At that price point, you're partly self-insuring against minor workmanship issues.

Manufacturer warranties for panels, inverters, and batteries exist independently of the installer. Even if your installer closes tomorrow, you can pursue a Tier-1 panel or battery warranty claim directly through the brand's Indonesia distributor. Keep your purchase receipts, serial numbers, and signed installer quote somewhere you'll find them in 8 years.

And the honest bottom line: a warranty is only as good as the company standing behind it. Long warranty clauses from an 18-month-old CV mean less than shorter clauses from a PT with a decade of Indonesia residential installs. We'd rather tell you that up front than have you learn it the hard way.

Ready to size your home?

If you're at the point of researching warranty questions, you're close to a decision. The fastest next step is a free remote sizing from us. Send us your location, PLN connection rating, and a recent bill. We'll come back with a system size, an honest cost range, and an installer option from our vetted network, including all the warranty criteria covered above.

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