Solar analyzer · Singapore landed homes only

See What Your Roof Can Actually Do.

We use Google's roof imagery and your home's actual address to show you a real solar analysis — not a generic estimate. See how many panels fit, what you'd generate, and what payback looks like for your specific roof.

Step 1 · Your details

Get your roof analysis

Free. No obligation. We use your details to send you the result and follow up only if you ask us to.

We'll send you a copy of the analysis if you'd like.
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Your details stay with Wong Lye. We won't share or sell them. Singapore PDPA compliant.
Already know your panel count?

Quick estimate.

Enter how many 650W panels you want, and the rate and usage from your bill. Payback uses those figures. It is not the same for every roof.

SP Simplified Credit Treatment for a home: the tariff before GST, minus 6.10 cents of network costs. Filled in at 22.49 cents for the Q4 2026 tariff. Edit it if your bill shows a different credit.

The share of your monthly use that falls in daylight, about 9am to 5pm, when the panels can cover it. Solar cannot offset evening use. 35% is a starting point for a landed home.

System size—
Annual generation—
Yearly saving—
Wong Lye Solar price—
Payback—

This estimate has no address, so generation is 1,282 kWh per kWp (SERIS) plus a 5% bifacial gain. A roof analysis uses Google's sun data for that roof when we have it. Yearly saving is power used at home, plus the export credit, minus maintenance at 1% of the system cost. Indicative, at 650W per panel and prices incl. GST. The final fixed price is confirmed at the free site survey, where we check roof access (scaffolding), roof condition and the electrical run. For a quote tied to your actual roof, use the analysis above.

How this works

Real Data. Honest Numbers.

1

Google Solar API

We pull roof imagery and orientation data from Google's Solar API — the same dataset Google uses for Project Sunroof. It analyzes your specific roof, not a typical home. Where that data includes a sun figure for the roof, generation uses it. Where it does not, we use 1,282 kWh per kWp (SERIS) and a bifacial gain of at most 5%.

2

Your panel size, your numbers

Most calculators use generic 400W panels. We calculate with the 650W bifacial panels we actually install — the newest generation, far more power from the same roof space. Less space, more power, accurate for what we'd build.

3

Singapore tariff economics

Power you use at home in the daytime is worth the rate on your bill. Surplus exported to SP Group earns the Simplified Credit Treatment credit, which is lower. Maintenance is 1% of the system cost a year, and it is taken off before the payback. One payback figure for every roof is not a real number.

4

What the calculator can't see

Roof structural condition, age of trusses, future shading from neighbouring rebuilds. As a BCA General Builder, we look at the structural side too — that's the part pure solar vendors miss.

Common questions

Solar for Landed Homes in Singapore.

Is solar worth it for a landed home in Singapore?
For most landed homes with usable roof area and daytime power use, yes. Singapore averages 4.5 peak sun hours a day, so a 10–15 kWp system on a typical landed roof generates 12,000–18,000 kWh a year. What you use at home in the daytime saves your own electricity rate. Surplus exported to SP Group earns the Simplified Credit Treatment credit, which is lower. The payback follows from your bill and your roof. The variable that ruins it is shading from neighbouring rebuilds — that is the part the calculator cannot see and we check on site.
How many solar panels can fit on a Singapore landed home roof?
Typical Singapore landed roofs fit between 14 and 36 panels depending on plot size, roof pitch, and obstructions like skylights, water tanks, and parapet setbacks. We install 650W bifacial panels (Trina Vertex N) — the newest generation available, delivering far more power than standard 400W panels from the same roof space. When roof area is the constraint, which it almost always is on landed homes, that difference decides whether solar is worth doing at all.
What is the payback period for solar on a landed home in Singapore?
It depends on your electricity rate, how much of your use happens in daylight, and what your own roof generates. Power used at home saves the rate on your bill. Surplus exported under Simplified Credit Treatment earns the lower credit described below, not 10–15 cents. Maintenance at 1% of the system cost is taken off before the payback. Enter your rate and your monthly use, or your monthly bill, and the calculator works it out. Shading from a neighbour's rebuild is the part we still have to check on site.
Do I need to reinforce my landed home roof for solar panels?
Sometimes, yes. Each 650W bifacial panel weighs about 33kg, plus mounting rails. A 20-panel system adds roughly 700–900kg distributed across the roof. Reinforced concrete roofs on landed homes built after the 1990s are usually fine. Older clay-tile or lightweight metal roofs often need structural review — and that is where pure solar vendors miss things. As a BCA General Builder, we assess the structure before quoting panels.
Can I sell excess solar power back to the grid in Singapore?
Yes. A landed home exports its surplus under SP Group's Simplified Credit Treatment (SCT). The credit is lower than the rate you pay: it is the regulated tariff before GST, minus 6.10 cents per kWh of network costs. On the Q4 2026 tariff of 31.16 cents including GST, that is 22.49 cents per kWh. It is not 10–15 cents, and it is not the SLEP rate. The calculator fills 22.49 in, and you can change it to the credit on your bill. We handle the SP Group registration as part of the install.
How long do solar panels last in Singapore's climate?
Quality panels carry a 25–30 year power warranty, guaranteeing ~85–87% of original output at end of warranty. Our Trina panels carry a 12-year product warranty and 30-year power warranty to 87.4%. Singapore's heat does accelerate degradation slightly compared to temperate climates, which is why we use the Trina N-type bifacial spec — it degrades at 0.4% a year instead of the industry-typical 0.5–0.6%.
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