Workmanship vs Manufacturer vs Installer Warranty: What Solar Homeowners in Singapore Need to Know

Most solar quotes for a landed home in Singapore list one warranty figure and leave it there. Usually “25 years”, printed as if the whole system is covered for a quarter of a century. That single number hides three separate promises made by two different parties: the manufacturer that built the panels and inverter, and the installer that put them on your roof.

Get it wrong and a warranty dispute between two parties who both think it is the other one’s problem is not a fast process, and the day something breaks is a bad time to find out.

The Key Difference at a Glance

The split is simple once you see it. The manufacturer guarantees the product. The installer guarantees the work. A panel can fail from a factory defect, which is the manufacturer’s problem, or from bad mounting and wiring, which is the installer’s. Same broken panel, two completely different claims, two completely different people to call.

The naming causes half the confusion.

“Installer warranty” and “workmanship warranty” are the same thing, and a “contractor workmanship warranty” is that same thing with a longer name. All three describe the installer backing the quality of the work. A manufacturer’s warranty backs the hardware.

One practical detail matters. In Singapore, panel and inverter warranties are registered with the manufacturers, not your installer. Your installer usually files claims for you, which is convenient right up until they close down. If they close down, however, the claim becomes yours to file, and only works if you kept your own copies of the serial numbers and warranty certificates.

Manufacturer Warranty: What the Product Maker Covers

What it is: This is the warranty from whoever built the panels or the inverter.

What it covers	What it does not cover
Factory defects in the hardware: cracked cells, delamination, junction box failures, frame defects	Any failure caused by bad installation
Premature physical failure of the product itself	Storm or weather damage
Material faults that appear over time	Normal wear and tear, or a system left unmaintained

For the panels, the manufacturer warranty splits into two:

Product warranty (12 to 15 years): covers manufacturing defects in the panel itself.
Performance warranty (25 to 30 years): guarantees a minimum output over time, typically around 97% in year one, easing to roughly 84% to 87% by year 25.

Inverters have their own manufacturer warranty, usually 5 to 12 years as standard. They are the most failure-prone component in the system, and replacing one in Singapore costs S$2,000 to S$8,000. An extended warranty to 15 or 20 years, bought upfront, is usually money well spent.

Limitations:

The manufacturer covers the product, not the installation. If an installation error caused the fault, the manufacturer declines the claim and points you back at your installer. Call the wrong party and the claim goes nowhere.
One thing worth knowing before you count on a performance warranty alone. Proving a panel has fallen below its guaranteed output usually means removing it and shipping it to an approved independent lab, at your cost up front, refunded only if the test confirms the fault is theirs. On a single panel, that can cost more than a replacement.

What to do: Product, performance and the installer’s workmanship warranty are the three types you are actually dealing with, even when the quote shows a single number. For instance, a quote that says ’25-year warranty’ without specifying which warranty it refers to is like a property listing that says ‘fully renovated’ without specifying what was actually done. So, be sure to ask which warranty covers what, and for how long.

Installer Warranty, Also Called Workmanship Warranty: What the Contractor Covers

So what is a workmanship warranty, in plain terms?

What it is: It is the installer’s promise that the work itself was done properly. By definition, it covers mistakes in the installation:

Improperly sealed roof penetrations that let water in
Loose or incorrect wiring connections
Incorrect mounting or racking
Poor cable management
A system that does not match the specification you were quoted

Manufacturing defects, storm damage and misuse are somebody else’s department.

Limitations:

The length of the warranty is where it gets inconsistent. Workmanship warranties run from 1 to 10 years, entirely down to the individual contractor, and plenty of installers offer nothing once the initial defects period ends.
Ask an installer what warranty they offer, and some point at the 25 and 30-year figures on the panels and inverter. Those are the manufacturer’s warranties on the equipment, and they say nothing about the installation itself.

What to do: Ask every installer for their workmanship warranty in writing, with the scope defined. If they cannot produce one, or offer less than 5 years, treat that as part of the quote comparison.

The Defects Liability Period, and Why It Is Not a Warranty

There is also another term to consider: Defects Liability Period (DLP).

What it is: The DLP gets mistaken for a workmanship warranty, and it is not one. It is a construction-contract mechanism common across Singapore’s building industry, usually 12 to 24 months from commissioning.

Inside that window, the installer has to fix workmanship defects and anything that does not match the agreed specification, at their own cost.

What the DLP does not cover:

Manufacturer defects in the equipment
Gradual performance decline
Weather or storm damage
Anything at all once the window closes

Limitations: After it expires, an inverter failure or wiring fault is yours to resolve unless a separate workmanship warranty is still running.

What to do: Pin down the start date in the contract before signing. The DLP clock starts at commissioning, when the system is tested, connected to the SP Group grid, and formally accepted, not on the day the panels went up.

	Manufacturer warranty	Installer / Workmanship warranty	Defects Liability Period
Who backs it	Panel or inverter maker	Your installer	Your installer
Covers	Factory defects in the hardware	Faults in how it was installed	Workmanship defects, spec mismatches
Excludes	Bad installation, weather, wear	Manufacturing defects, weather, misuse	Equipment defects, performance decline, post-window faults
Typical length	Panels 12-15 yrs product, 25-30 yrs performance; inverters 5-12 yrs	1-10 yrs, contractor-dependent	12-24 months from commissioning
If the installer closes	Still claimable direct with the maker	Void	Void

What Happens When Something Goes Wrong

Match the fault to the right party, and the process is straightforward.

A manufacturing defect goes to the manufacturer or their authorised Singapore representative. Your installer can lodge it for you; if they have shut down, you file it yourself with your documentation and serial numbers.
An installation error inside the DLP or workmanship period goes to your installer. Put it in writing and keep copies.
If your installer has gone out of business, the DLP and workmanship warranty are void. The manufacturer warranties survive, but only if you kept the documentation and registration records yourself.

Warranties can also be voided from your side. For example, skipped maintenance, modifications by unauthorised parties and improper use can all invalidate your warranty coverage, and some manufacturer warranties require proof of regular professional maintenance to stay valid.

This is one place our Rent-to-Own model changes the maths on risk.

Because FOMO Energy owns the system through the rental period, the cost of troubleshooting and repairs falls to us, not you, if the system underperforms. Keeping it running well is our problem as much as yours, a very different arrangement from an installer paid in full on handover day and already on to the next roof.

10 Contract Clauses to Check Before You Sign

All of this is easier when the contract spells it out in the first place.

Before signing any home solar installation contract, go through these ten clauses and make sure each is answered on paper, not just in conversation:

System specifications: Exact panel model, quantity, inverter model, total kWp. Any change without your written consent should count as a breach.

Performance guarantee: Whether one is included, the metric used, and the remedy if the system underperforms.

Timeline and delays: Installation and completion dates, and what happens if they slip.

Permits and approvals: Who handles BCA structural approval and SP Group grid connection. This is the installer’s job, and the contract should say so.

Roof warranty protection: Confirmation that the installation will not void your existing roof warranty, and that the installer is liable for any roof damage caused by their work.

Monitoring and maintenance: What monitoring is included and whether ongoing maintenance terms are defined.

Termination and cancellation: How either side exits, the financial consequences, and any cooling-off period.

Dispute resolution: How disagreements are handled and the jurisdiction that applies.

Assignment and transfer: Whether the installer can subcontract, and whether the contract passes to a new owner if you sell.

Insurance during installation: Whether the installer carries professional indemnity and workmen’s compensation cover. Ask for copies.

The same checklist applies to a commercial solar panel system. Bigger numbers and more people signing off, but the warranty structure behind it works exactly the same way.

Why Your Installer’s Track Record Matters as Much as Their Warranty

A workmanship warranty is only as reliable as the company that wrote it. A 10-year promise is worthless if the business is gone by year four, because there is nobody left to honour it.

FOMO Energy runs in-house construction teams with a track record of landed-home installations across Singapore and backs the work with ongoing O&M under our REConnect programme. The people who installed your system are also the same people monitoring it years later, so there is no handover to a third party.

Know exactly what your solar warranty covers before you sign anything. Talk to our team about what our installation cover and O&M under the REConnect programme actually include.