Solar calculator for Philippine homes
A useful solar calculator should help you form better questions before requesting proposals. It should not pretend to replace a site survey, electrical design, structural review, or utility approval.
Planning guidance only
Verify the site, equipment, permits, utility rules, and written proposal before spending.
Start with your electricity use
Use the kWh shown on recent bills whenever possible. A peso bill can be converted into a starting estimate, but tariffs and non-energy charges vary, so the bill’s kWh figure is more reliable.
Daytime consumption matters because energy used while the panels are producing is normally the easiest solar energy to use directly.
Collect 6–12 recent bills.
Note daytime loads such as cooling, pumps, refrigeration, and work-from-home equipment.
Record whether brownout backup is a priority.
Treat the result as a planning range
Roof geometry, shade, weather, inverter selection, export arrangements, wiring, and equipment losses can move the final recommendation.
Run the calculator, save the assumptions, then ask installers to explain why their proposed capacity differs from your starting estimate.
Inputs that improve a Philippine estimate
The strongest input is monthly kWh from the bill, followed by daytime-use share, roof area, shade, and whether backup power matters. A peso-only bill estimate is useful for starting, but it can be distorted by tariff changes and charges that solar does not remove.
Use a low, expected, and high case instead of treating one result as guaranteed. The calculator should help you prepare a realistic range for an installer discussion, not create a final system design.
Replace bill-derived kWh with the actual kWh printed on the bill.
Separate daytime consumption from evening consumption.
Record major future loads such as another air-conditioner, pump, or electric vehicle.
Confirm roof dimensions and shade during a site visit.