How we estimate

Effective 6 November 2026 · Solarify by Genetrify Information Technology Services

Model 2026-11-06.1. A deliberately simplified planning calculation. Your rate, daytime use, loads and roof inputs can be changed in the calculator; local utility tariffs and site-specific design are not verified by Solarify.

From a bill to energy

Monthly kWh ≈ entered bill ÷ blended electricity rate. Daily kWh = monthly kWh ÷ 30. The initial PHP12/kWh rate is an editable assumption, not a current SOCOTECO, Meralco or other utility tariff. Actual daily kWh can be entered instead of a bill. With neither figure, personalised PV capacity and savings are not fabricated.

Panels and direct use

Target PV kWp = daily kWh × daytime share ÷ (4.0 assumed sun-hours × 0.78 performance ratio × shade factor). The array rounds up in illustrative 550 W modules. Direct self-use = 0.80 × the smaller of potential generation and daytime consumption. The overlap factor accounts simply for imperfect timing; it is not a measured household result.

Sun-hours, performance and overlap values are Solarify assumptions, not official regional averages. The same initial resource assumption is used across island groups until site-specific information is supplied. Unmatched potential is not a prediction of actual grid exports; all export value is zero in this model.

Roof and inverter classes

A 550 W panel example uses 2.278 × 1.134 m with a 25% rough planning space allowance. Entered usable roof area limits panel count and recalculates output. This arithmetic does not check layout, structure, setbacks or safe access. Preliminary inverter classes consider PV power divided by 1.2 and, for backup, 1.25 times selected running load. Starting surges, phase, manufacturer limits and compatibility still require installer assessment.

Battery reserve

Nominal kWh = selected average load in watts × requested hours ÷ 1,000 ÷ 0.80 usable fraction ÷ 0.90 discharge efficiency. Capacity rounds up in illustrative 5.12 kWh increments. Fridge/air-conditioner duty factors are editable examples of on-time. Battery reserve adds no extra recurring bill savings to avoid counting the same solar energy twice. Off-grid autonomy requires a fuller assessment and is not calculated as a reliable off-grid design.

Budget envelope

For supported 2–10 kWp grid-connected scenarios, the indicative PV envelope is PHP30,000–75,000 per kWp. A battery-capable system adds a rough PHP20,000–40,000 allowance plus PHP8,000–15,000 per nominal battery kWh. Displayed limits round outwards to PHP5,000. These are our broad heuristics, not supplier component prices or market bounds.

Public reference packages were checked 5 November 2026. Expired Juansolar promotions were excluded. Differences in scope, territory and equipment mean the packages are not directly interchangeable. Outside the supported range or with insufficient inputs, Solarify asks for a site quotation instead of extrapolating a price.

Other technical references

PVWatts loss documentation treats losses in more detail. Solarify is not PVWatts and does not describe its single performance ratio as that model. Global Solar Atlas methodology explains generalized modeled solar resource and output; its PV output should not be reduced by a second performance ratio.

Quote checklist

Confirm actual loads, roof condition, shade, phase, battery output, equipment models, warranties, delivery, mounting, electrical work, permits, net-metering, labour and commissioning. The downloadable report includes these open questions so you can compare written proposals.