Know your numbers before you commit to a system.

Note — panel degradation basis: every figure in this section (both payback periods, all seven investment ratios, and the chart/table below) assumes solar output declines over time rather than staying constant — it does not assume your panels perform at year-1 output for all 25 years. This follows the actual manufacturer warranty curve for the JA Solar JAM66D45 LB (620W) panel used in this system: 1% degradation in year 1, then a flat 0.4%/yr afterward (linear, not compounding), matching JA Solar's published 30-year linear performance warranty of at least 87.4% of rated output remaining at year 30.

Demand growth assumes 5.5%/yr compounding (Base Case), based on Philippine DOE distribution-utility planning (~5–5.5%/yr through 2028–2040) and the historical 1982–2015 residential trend (5.8–5.96%/yr), driven by rising household income, electrification, and appliance/cooling ownership.

Note — basis for this forecast: PTG Solar uses a deliberately conservative Base Case of 6%/yr for the Meralco rate escalation shown above and used throughout this projection. Meralco's actual residential rate rose from a pandemic-era low of about ₱8.3/kWh (March 2021) to about ₱14.35/kWh (April 2026) — roughly 10–11%/yr over that stretch — while the longer 10-year historical average (2016–2025) runs closer to 5%/yr. PTG Solar models three scenarios: Conservative 4%/yr (below the 10-year historical average, a lower-bound planning case), Base Case 6%/yr (the figure used throughout this projection — deliberately below both the long-run average and the recent post-pandemic trend, so as not to overstate your savings), and Aggressive 8%/yr (a stress-test case, still below the actual realized rate of increase from 2021–2026). Source: Meralco's official monthly rate announcements, 2021–2026.