Rooftop solar in 2026: is it worth it & what's the payback?
High electricity bills make rooftop solar appealing — but whether it pays off depends on your usage and system size. Here's a simple breakdown.
System types
ภาพ: André Karwath aka Aka — CC BY-SA (wikimedia)
- On-grid: connected to the grid, uses daytime sun and normal power at night (most popular, best value for typical homes)
- Hybrid: adds batteries for night use (higher cost)
- Off-grid: not grid-connected, for remote areas
Cost and payback (approximate)
| System size | Approx. install cost | Approx. monthly saving |
|---|---|---|
| 3 kW | ~90,000–130,000 THB | ~1,000–1,800 THB |
| 5 kW | ~150,000–200,000 THB | ~1,800–3,000 THB |
| 10 kW | ~300,000–400,000 THB | ~3,500–6,000 THB |
Typical payback is around 6–10 years, depending on how much daytime power you use (panels last 20–25 years).
When it's most worth it
- Heavy daytime usage (home all day / WFH / daytime air-con)
- High monthly bills (the higher, the faster the payback)
- A sunny roof with no shading
Watch out for
Photo: Daniel L. Lu (user:dllu) — CC BY-SA (wikimedia)
- Choose a certified installer with panel/inverter warranty
- Get permits / meter change done properly
- Beware oversizing — match the system to your daytime usage
Verdict
Rooftop solar is best for homes with high daytime usage and big bills — payback around 6–10 years, then near-"free" power for years after. Assess your daytime usage before deciding. If you also need overnight or portable backup power, see our guide on portable power stations.
Figures are approximate — they depend on the installer, equipment and usage.
Sources
Photo: U.S. Department of Energy — CC CC0 (rawpixel)
- Installer/equipment maker data
- Utility permit requirements
Frequently asked questions
- Which homes benefit most from solar?
- Homes that use a lot of power during the day (people at home, work-from-home, daytime air-con) benefit most, since they use the generated power immediately.
- Do I need a permit to install?
- Grid-connected (on-grid) systems require permission and may need a meter change. Use a certified installer who handles the paperwork.
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