How Many Solar Panels Do You Need? (Philippine Homes, 2026)
Somewhere between three and seventeen. Helpful, di ba? The honest answer depends on exactly one document you already own: your latest bill. Three steps take you from that bill to a panel count, and there’s a lookup table below if you’d rather skip the arithmetic.
Step one. Divide the bill by the current Meralco rate (₱14.74/kWh, September 2026). A ₱4,000 bill is about 271 kWh a month — call it 9.0 kWh a day.
Step two. Divide daily usage by what a panel-hour actually delivers here: 4.5 peak sun hours times 0.80 for real-world losses. So 9.0 ÷ 3.6 ≈ 2.5 kWp.
Step three. Divide by panel size. Installers here mostly fit 580 W panels now, so 2,500 ÷ 580 rounds up to 5 panels, about 13 m² of roof.
The lookup table
100% offset, September 2026 rate, 580 W panels:
| Monthly bill | Usage | System | Panels | Roof area |
|---|---|---|---|---|
| ₱2,500 | 170 kWh | 1.6 kWp | 3 | 8 m² |
| ₱4,000 | 271 kWh | 2.5 kWp | 5 | 13 m² |
| ₱5,000 | 339 kWh | 3.1 kWp | 6 | 16 m² |
| ₱7,500 | 509 kWh | 4.7 kWp | 9 | 24 m² |
| ₱10,000 | 678 kWh | 6.3 kWp | 11 | 29 m² |
| ₱15,000 | 1,017 kWh | 9.4 kWp | 17 | 45 m² |
In-between bill? The solar panel calculator takes any amount and lets you adjust the sun-hours and offset assumptions yourself.
When fewer panels beat more panels
The table assumes you can use or export everything the roof makes. But exports only earn ~₱6/kWh in net-metering credits, versus the ~₱14.74 you avoid when you consume solar directly. If the house sits empty on weekdays, a system at 60–75% of the table size usually delivers better pesos-per-peso — the payback calculator will show you that trade-off with your own numbers instead of a rule of thumb.
One roof reality before you count panels
Panels want contiguous, unshaded space. A vent pipe’s little shadow sliding across a panel at 10 a.m. costs more output than you’d believe, and it costs it every single day. South-facing is ideal; east or west works at maybe 10–15% less, which one extra panel usually covers. Let the installer’s site survey argue with your roof — your job is walking in already knowing the right system size.