How to Choose a Solar Installer in Singapore: 7 Questions to Ask Before Signing

The solar industry in Singapore has grown rapidly over the past five years, and with that growth has come a wide range of installers — from well-established operators with hundreds of completed projects to newer entrants whose quality and reliability are harder to assess.

A solar system is a 25-year asset. Choosing the wrong installer doesn't just mean a bad experience; it can mean a system that underperforms, warranties that are hard to claim, and a company that may not exist by the time you need post-installation support.

Here are the seven questions that matter most before you sign anything.

1. Is Installation Done In-House or Subcontracted?

This is perhaps the single most important question you can ask. Many solar companies in Singapore act as sales and project management entities and outsource the actual installation to third-party contractors. This is not inherently wrong, but it creates accountability gaps.

When something goes wrong — a tile is cracked, a cable is incorrectly routed, a panel is not generating at expected output — who is responsible? The sales company? The subcontractor? These disputes are not hypothetical.

An installer with a fully in-house installation team means one point of contact for everything: design, installation, commissioning, and after-sales. The people who installed your system are the same people who answer the phone if something goes wrong.

Ask directly: "Is your installation team employed by your company, or do you subcontract?"

2. Who Handles the LEW Submission and SP Group Application?

In Singapore, any work that connects a solar system to the electrical grid must be certified by a Licensed Electrical Worker (LEW) registered with the Energy Market Authority. Additionally, connecting to SP Group's grid for export requires an ECIS application, which involves meter upgrades and a formal grid connection process.

Some installers quote a system price and then expect you to arrange or pay separately for LEW certification and SP Group paperwork. Others include it all.

Ask: "Is LEW submission and SP Group grid connection included in your quote? Who handles the paperwork?"

A complete service should include both — and it should be completed without you needing to chase anyone.

3. What Panel Brand and Tier Are You Quoting?

Not all solar panels are equal. The solar panel market includes products from Tier 1 BloombergNEF-rated manufacturers — companies with verified production scale, bankability, and warranty backstop — down to no-name modules with uncertain provenance and unclear warranty support.

Tier 1 is not a quality rating; it's a bankability rating. But it is a useful proxy for warranty reliability, because a Tier 1 manufacturer is significantly less likely to go out of business before your 25-year product warranty expires.

Ask: "Is the panel you're quoting a BloombergNEF Tier 1 manufacturer? What is the efficiency rating of the specific model?"

For Singapore's climate, N-type monocrystalline panels — particularly N-type ABC technology — offer the best combination of efficiency, temperature performance, and longevity. Check that the quoted panel is not a lower-tier product being sold at a Tier 1 price.

4. What Does the Workmanship Warranty Cover — and for How Long?

Panel and inverter warranties are product warranties provided by manufacturers. The workmanship warranty is the installer's own guarantee that the installation itself — cable routing, mounting, weatherproofing, electrical connections — was done correctly and will hold.

A short workmanship warranty (one year or less) is a red flag. A quality installer should offer at least five years. Ask what specifically is covered: does it include roof penetration waterproofing? Does it cover re-routing of cables if they cause roof issues? What is the claims process?

Separately, ask about the waterproofing warranty — some installers offer this as a distinct guarantee on the roof penetrations themselves. A two-year waterproofing warranty is reasonable and reflects confidence in the mounting system.

5. Is Real-Time Monitoring Included?

A solar system that is generating normally looks identical from the outside to one with a faulty string or a shading issue that's costing you 20% of your output. Without monitoring, you have no visibility into whether your system is performing as designed.

Quality inverters come with cloud-based monitoring platforms included. The Sungrow iSolarCloud platform, for example, provides real-time power output, daily and cumulative generation figures, export vs self-consumption breakdown, and fault alerts — accessible via mobile or desktop. It won a Red Dot Design Award in 2024, reflecting both its functionality and usability.

Ask: "Is a monitoring platform included? Can I see live generation data on my phone? Will I be alerted if something goes wrong?"

If monitoring requires a separate subscription or is not mentioned at all, that is worth noting.

6. What Is the Difference Between Estimated and Guaranteed Generation?

Every proposal will include a generation figure — typically expressed as kilowatt-hours per year. The key question is whether that figure is estimated or guaranteed.

An estimated figure is based on simulation data using historical irradiance records, panel specifications, and assumed losses. It is a reasonable projection but carries uncertainty — weather varies, shading may be different than modelled, and the simulation software is only as good as the inputs.

A guaranteed figure is a contractual commitment. If the system generates less than the guaranteed amount in the first year (typically measured and verified via monitoring data), the installer is obligated to remedy the shortfall. This might mean additional panels, compensation, or remediation work.

Ask: "What is the guaranteed first-year generation figure, and how is it measured and enforced?"

The gap between estimated and guaranteed is also informative: a well-designed system with realistic assumptions might show a 10–15% gap. A proposal where the "guaranteed" figure is essentially the same as the estimated one warrants scrutiny.

7. What Is the Payment Milestone Structure?

Reputable solar installers in Singapore typically structure payment across milestones tied to project progress — not a 100% upfront payment before work begins.

A reasonable structure looks something like: 60% upon contract signing and procurement commencement, 30% upon installation completion, 5% upon internal commissioning, and 5% upon SP Group turn-on and handover.

This structure protects you. If the installer fails to commission the system, you haven't paid in full. If SP Group connection is delayed, your final payment is withheld accordingly.

Be cautious of any quote requiring full payment upfront or a single large payment before installation is completed.

A Simple Checklist

Before signing with any solar installer in Singapore, confirm:

• Installation team is in-house (not subcontracted)
• LEW submission and SP Group application are included in the price
• Panels are BloombergNEF Tier 1, ideally N-type monocrystalline
• Workmanship warranty is at least 5 years
• Real-time monitoring is included at no extra cost
• A guaranteed (not just estimated) generation figure is provided
• Payment is structured across milestones, not 100% upfront