The short version: eight months in, the array covers roughly two-thirds to three-quarters of the house and is tracking to a ~3.0-year payback. Charging days still pull ~23 kWh from the grid versus ~8 kWh otherwise, but the correction this month is that retiming the PHEV charge recovers less than it looks: those days export nothing at all, so there is no idle midday surplus for the car to absorb. The money is in the overnight base load — ~4.3 kWh bought at the full rate every night while the battery sits empty, about ₱25,000 a year. If you're sizing a system here, the variable that generalizes from this single-site data is the always-on load floor, not panel count. Once it was running I also took it through Meralco net metering — that paperwork is its own story: Net Metering Journey in General Trias.
Headline numbers
Annual bill cut
₱132,289
~68% of pre-solar bill
Simple payback
~3.0 yrs
on ₱400k turnkey
Year-1 generation
~8,432 kWh
~23.1 kWh/day baseline
CO₂ avoided
~5.4 t/yr
≈244 trees · 25,500 km
What the data shows
Self-sufficiency climbed from 54% in December to a peak of 77% in March, eased to ~70% across April and May as household consumption rose (avg daily load went from ~29 to ~39 kWh), then dropped to ~60% in June as the wet season arrived. July recovered most of that: generation rose ~8% to ~25.4 kWh/day, load eased ~5%, and self-sufficiency came back to ~66% with grid import down from ~462 to ~377 kWh. June had six deeply overcast days against July's one — ordinary wet-season variation, not a system problem.
No equipment fault is visible. Peak PV reached 5.4 kW (68% of inverter capacity), and there is still zero clipping in 242 days. July's raw battery round-trip efficiency reads 91.9%, below the 94–98% band of every prior month, but that is an artefact of where the month happened to start and end: the pack opened at 11% state of charge and closed at 92%, so ~11.5 kWh was charged in July and discharges in August. Credited back, July is ~96%. August should show the mirror image and read artificially high.
The highest-impact lever is the overnight base load — a ~630–950 W floor that draws ~4.3 kWh from the grid between midnight and 07:00, after the battery has emptied. Every 100 W trimmed off it is worth ~₱14,000 a year, and it repeats whether anyone is home or not. See recommendations →
Monthly bill impact
Month
Bill without solar
Net savings
Dec 2025
₱13,424
₱7,291
Jan 2026
₱11,736
₱7,039
Feb 2026
₱10,609
₱8,420
Mar 2026
₱12,464
₱10,520
Apr 2026
₱17,542
₱12,165
May 2026
₱18,633
₱13,162
Jun 2026
₱18,539
₱11,144
Jul 2026
₱18,001
₱12,129
Net savings peaked in May at ₱13,162 and eased to ₱11,144 in June as the wet-season generation dip pushed load onto the grid, then recovered to ₱12,129 in July. Each month is billed at the rate that applied then (rates climbed from ₱14.41 in December to ₱16.00 in July, peaking at ₱16.10 in June); the ~₱132k annual figure is projected at today's rate.
Disclaimer: the report is AI-assisted. While the underlying data comes from the inverter export, the narrative analysis, recommendations, projections, and financial interpretation may contain inaccuracies. Verify critical findings against your own records, manufacturer specs, or a qualified solar professional before acting on them.