How this calculator works
Your monthly bill divided by your rate gives your consumption in kilowatt-hours. The Philippines averages about 4.5 peak sun hours per day, so each kilowatt-peak (kWp) of panels produces roughly 110–120 kWh per month. We size the system to cover your usage, then split the value of that production two ways: energy you consume as it's generated saves at your full retail rate, while surplus exported to the grid under net metering is credited at roughly 38% of retail. That's why your daytime-usage slider moves the payback number so much — self-consumption is where the real money is.
What the numbers don't capture
Roof orientation and shading, panel and inverter brand, and installation quality all shift real-world output. Panels typically carry a 10–12 year product warranty plus a 25-year linear performance guarantee, so the long-term math holds up — but only if the installation is done right. That's why we track which providers are PCAB-licensed: it's a strong quality signal from a government accreditation body, and worth looking for when you compare quotes. You can read our full guide on choosing a solar installer in the Philippines or go deeper on payback periods and calculating ROI from your Meralco bill.