Quick answer: Before signing any solar contract in Singapore, verify 25 items across 5 categories: installer credentials (BCA-licensed, EMA-approved), system specs (panel wattage, inverter brand, warranty terms), pricing transparency (per-watt cost, included items, hidden fees), timeline (typical: 4–8 weeks contract to power-on), and aftercare (monitoring, maintenance, insurance, performance guarantee).
Source: Sunollo Buyer's Checklist, 25-question framework. Updated 2026 Q2.
The Complete Solar Buyer’s Checklist Singapore: 25 Questions to Ask Before You Sign
Solar is a long-term investment in Singapore: you are committing to equipment on your roof, grid connection rules, and a contract that may span a decade or more. Before you sign, use this checklist to turn vague sales talk into clear, comparable answers.
If you are still calibrating expectations, start with our 15 Solar Myths guide. For numbers and risk language, pair this checklist with our P50/P90 guide, degradation guide, and Solar Panel Cost guide. When ready to compare installers, use our guide to choosing the best solar company and contract and warranty guide.
1. About the Company (Questions 1–5)
1. How long have you been installing solar in Singapore?
Why it matters: Local experience with roof types, permits, and SP Group processes reduces rework and compliance risk.
Good answer: Clear timeline with examples by property type. Red flag: “Our factory overseas has 20 years’ experience” with no local evidence.
2. How many installations have you completed, and can you provide references?
Why it matters: Scale helps judge whether claims are marketing or operational reality.
Good answer: Reasonable count plus 2–3 verifiable references. Red flag: Huge numbers with zero references.
3. Are you registered with SP Group for solar connection processes?
Why it matters: Grid connection follows regulated steps; confusion here delays energisation.
Good answer: Confirmed registration with documented workflow. Red flag: “SP will sort it out automatically.”
4. Which Licensed Electrical Worker (LEW) will sign off my installation?
Why it matters: Electrical safety and compliance are not optional in Singapore.
Good answer: LEW named or assignment process explained with documentation provided. Red flag: Refusal to discuss LEW involvement.
5. Can you provide two recent references from similar roof types?
Why it matters: References bridge the gap between polished proposals and field execution.
Good answer: Willingness to connect you with recent customers. Red flag: Only overseas references or aggressive pushback.
2. About the Equipment (Questions 6–10)
6. Which exact panel brand and model are you proposing?
Why it matters: “Tier 1” is not a specification. Efficiency, temperature behaviour, and warranty terms vary by model.
Good answer: Specific part number with datasheet and warranty document. Red flag: “We will choose panels later.”
7. Which inverter brand and model, and what is the warranty term?
Why it matters: The inverter is the highest-impact component for uptime.
Good answer: Named inverter, warranty years, labour inclusion, and replacement turnaround. Red flag: Non-standard inverter with no local support path.
8. Are the modules N-type or P-type?
Why it matters: Technology choice affects degradation, efficiency, and long-term yield. See our degradation guide.
Good answer: Concise comparison tied to your site conditions. Red flag: Buzzwords with no link to your roof or quoted yield.
9. What monitoring system will I get?
Why it matters: Without monitoring, you may not notice underperformance for months.
Good answer: Named platform, included sensors, alert settings, and retained access. Red flag: Monitoring as “optional add-on” with no baseline reporting.
10. What mounting hardware and waterproofing apply to my roof?
Why it matters: Singapore’s sun and rain cycles punish poor flashing and sealant choices.
Good answer: Roof-specific method with bracket types, sealant systems, and post-install photos. Red flag: “We never get leaks” with no technical detail.
3. About the Performance (Questions 11–15)
11. Is your production estimate P50 or P90?
Why it matters: A single kWh number can hide optimism. See our P50/P90 guide.
Good answer: Both P50 and P90 with listed assumptions. Red flag: Only the best month multiplied into an annual total.
12. How did you adjust for degradation over 25 years?
Why it matters: Proposals that ignore degradation overstate returns.
Good answer: Year-by-year model aligned to manufacturer warranty curves. Red flag: “Panels basically do not degrade.”
13. What self-consumption ratio are you assuming?
Why it matters: In Singapore, the value of solar depends heavily on how much you use on-site versus export.
Good answer: Transparent assumptions with sensitivity table. Red flag: Magically high ratio with no data inputs.
14. Did you perform a shading analysis?
Why it matters: Partial shading can disproportionately hurt production.
Good answer: Shading tool outputs, stringing rationale, and conservative treatment of uncertain obstructions. Red flag: “No shading issues” without visiting or modelling.
15. What methodology did you use to size the system?
Why it matters: Oversizing without a clear strategy wastes capital; undersizing may miss your target.
Good answer: Clear linkage among roof area, inverter choices, export assumptions, and target offset. Red flag: Sizing driven by sales incentives.
4. About the Contract (Questions 16–20)
16. What is the DLP duration and what does it cover?
Why it matters: The DLP is your early protection window for workmanship issues.
Good answer: Defined duration, scope, and reporting process. Red flag: DLP mentioned verbally but missing from the written contract.
17. What workmanship warranty do you provide beyond the DLP?
Why it matters: Workmanship warranties matter for roof integrity and long-term weatherproofing.
Good answer: Written term, exclusions, and insurance backing. Red flag: “Same as the panel warranty.”
18. What are the payment milestones?
Why it matters: Milestones should align incentives — you should not pay most of the contract before verifiable progress. See our contract and warranty guide.
Good answer: Balanced schedule tied to documented stages. Red flag: Near-total upfront payment.
19. Who is responsible for permits and SP Group coordination?
Why it matters: Administrative delays are a common project risk.
Good answer: Responsibility matrix with clear customer vs installer tasks. Red flag: Everything is “your problem” after signing.
20. Is there a performance guarantee?
Why it matters: Guarantees vary widely; the value is in measurable terms and fair verification.
Good answer: Defined baseline, acceptable variance, and remediation path. Red flag: Marketing guarantee with no measurable thresholds.
5. About After-Sales (Questions 21–25)
21. What maintenance plan do you recommend?
Why it matters: Soiling, debris, and equipment checks still matter in Singapore’s climate.
Good answer: Inspection cadence, cleaning guidance, and service package options. Red flag: “Solar is zero maintenance.”
22. Will I retain full monitoring access?
Why it matters: Vendor lock-in on data complicates ownership transfers and warranty disputes.
Good answer: Account ownership explained with export options. Red flag: Only the installer can see your production.
23. What is your response time for critical faults?
Why it matters: Downtime directly reduces savings.
Good answer: Business hours and emergency coverage with attendance windows. Red flag: No SLA at all.
24. If your company ceases operations, what happens to my warranties?
Why it matters: Manufacturer warranties may remain, but labour and coordination can vanish.
Good answer: Practical guidance on direct claims and third-party O&M options. Red flag: “That will never happen.”
25. What is the step-by-step warranty claim process?
Why it matters: Warranty paperwork is easy to promise and hard to execute.
Good answer: Written flowchart with evidence required, timelines, and cost allocation. Red flag: “We will handle everything” without specifics.
Conclusion
The best solar outcomes in Singapore are built from specifics: named equipment, honest production bands, licensed execution, and contracts that spell out who does what when something goes wrong. If you ask these 25 questions and keep written answers, you will compare installers on substance, not slogans.
Continue your research with our 15 Solar Myths guide, then deepen due diligence with our contract and warranty guide, P50/P90 guide, degradation guide, Solar Panel Cost guide, and guide to choosing the best solar company.
