Solar panel calculator
How many solar panels do you need? Type your monthly Meralco or electric co-op bill below. The calculator estimates your bill after solar, plus the system size, panels and roof space for the Philippine sun.
Your bill, in panels
Type your monthly electric bill. We'll estimate the system that covers it.
₱5,000about ₱710 a monthYou save about ₱4,290 a month (86%).
That's a 4.41 kWp system: 7 panels of 630 W on about 20 m² of roof, making about 476 kWh a month.
Estimate only, before your utility's fixed monthly charges. Your rate is on your Meralco or electric co-op bill. We assume 4.5 sun hours a day, 80% system efficiency, and net metering that credits exported power at about half your rate (the utility's generation cost, which changes monthly). Your free quote follows a site visit and covers grid-tie, hybrid or off-grid options. How this is worked out.
How the calculator works
- Monthly bill ÷ your rate per kWh = monthly kWh.
- Monthly kWh ÷ 30 = daily kWh.
- Daily kWh ÷ 3.6 (4.5 sun hours × 80% efficiency) = system size in kWp.
- kWp ÷ 0.63 kW = number of 630 W panels, rounded up.
Full worked example and a table by bill size in the guide size solar from your bill. For batteries, see battery backup in brownouts.
Calculator questions
₱5,000 billHow many solar panels do I need for a ₱5,000 bill?
About seven 630 W panels, or 4.4 kWp, assuming ₱12 per kWh, 4.5 sun hours a day and 80% system efficiency.
New billHow much will my electric bill be after solar?
It depends on when you use power. With net metering, solar you use directly saves your full rate, while power you export is credited at the lower generation cost. A ₱5,000 home bill used day and night drops to about ₱710 a month in our estimate; a ₱100,000 business bill used mostly in the daytime drops to about ₱9,600, plus fixed charges.
AccuracyHow accurate is the solar calculator?
It is a good first estimate. Shade, roof direction, how much power you use at night and your real rate per kWh change the final design, which we confirm at the site visit.
Your rateWhere do I find my rate per kWh?
Divide the total amount on your bill by the kWh you used that month. For example, ₱5,000 ÷ 400 kWh = ₱12.50 per kWh.
BatteryDoes the calculator include a battery?
No. It sizes the solar panels. A battery is sized separately, from the appliances you want running during a brownout.
More answers, with the numbers worked out, in our solar guides.
Turn the estimate into a quote
- Free site visit in Zambales and Pangasinan
- Written quote, no obligation
- We reply within one working day
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