What Size Solar System Do I Need for My Electric Bill? (Philippines)
TL;DR
Size your system off your bill, not a target panel count. A ₱5,000/month bill points to roughly a 3kW system, ₱8,000 to roughly 5kW, and ₱12,000 to roughly 8kW — each sized to offset most, not all, of your usage, since net metering underpays exported power.
The right way to size a solar system is to start from your average monthly electric bill, not from a target number of panels. As a rough guide: a ₱5,000/month bill points to roughly a 3kW system, an ₱8,000/month bill to roughly 5kW, and a ₱12,000/month bill to roughly 8kW — each sized to offset most, but not necessarily all, of your usage, since exporting excess power through net metering pays less than what you’d otherwise save by using it yourself.
Why size by bill instead of by panel count?
Because your bill is the number you actually have on hand — it’s printed on every statement, while your kWh consumption usually isn’t something you track directly. Panel count is really just the last step of a calculation that starts with the bill: bill to estimated kWh, kWh to system size in kW, and kW to panel count. Sizing by bill also keeps the focus on the number that matters financially — how much you’re spending — rather than an arbitrary panel target. For the panel-count math specifically, see our guide on how many solar panels you need; this guide focuses on what that system size costs and saves.
Bill-to-system-size table
| Monthly bill | Est. monthly kWh | Est. system size | Est. installed cost | Est. monthly saving |
|---|---|---|---|---|
| ₱3,000 | ~222 kWh | ~2kW | ~₱100,000-140,000 | ~₱1,800-2,700 |
| ₱5,000 | ~370 kWh | ~3kW | ~₱150,000-210,000 | ~₱3,000-4,500 |
| ₱8,000 | ~593 kWh | ~5kW | ~₱250,000-350,000 | ~₱4,800-7,200 |
| ₱12,000 | ~889 kWh | ~8kW | ~₱400,000-560,000 | ~₱7,200-10,800 |
| ₱18,000 | ~1,333 kWh | ~10kW | ~₱500,000-700,000 | ~₱10,800-16,200 |
Estimated monthly kWh comes from dividing the bill by roughly ₱13.50/kWh (Meralco’s 2026 all-in residential rate); system size comes from monthly kWh divided by roughly 120, an estimate of monthly output per kW under typical Philippine sun conditions. Installed cost assumes the standard ₱50,000-70,000 per kW grid-tied range; actual pricing depends on roof complexity, system size, and your installer. Monthly savings assume a 60-90% bill offset, the realistic range for a well-sized grid-tied system rather than a 100% target.
Why not just size for 100% of my bill?
Because net metering doesn’t pay you back at the same rate you save by using your own power. Exported electricity is credited at roughly ₱5-7/kWh, well under the retail rate you’d otherwise pay, so power your system generates while you’re not home to use it is worth less than power it offsets directly. Oversizing a system to chase a 100% offset means a growing share of your production goes toward those lower-value exports instead of full-value savings, which stretches out payback without matching gains in monthly savings. Most homeowners land on better returns sizing to comfortably cover their daytime and evening usage without deliberately overshooting it. See how net metering works for the mechanics behind that math.
How do I get a more accurate number than the table?
Pull your last 6-12 months of bills and average them, since a single month, especially a high-aircon month, skews the estimate. Our how to read your Meralco bill for solar sizing guide walks through exactly which line item to use and why your total amount due isn’t quite the same as your generation-related kWh usage. From there, the cost calculator runs the same bill-to-kWh-to-kW math automatically and matches it against current installed pricing, which is faster than doing it by hand and adjusts for details a flat table can’t capture.
Does a bigger system always mean bigger savings?
Not proportionally. Savings scale with how much of your system’s output you actually use or offset, not just with system size — see our guide on how much solar can save on your electric bill for how usage timing changes the math. An 8kW system on a ₱12,000 bill saves more in absolute pesos than a 3kW system on a ₱5,000 bill, but the percentage of the bill it cuts depends on how well the system size actually matches your usage pattern, not just on having more panels installed.
Where can I check actual current pricing for my system size?
Check our price pages for what systems of different sizes cost installed in your area, since ballpark per-kW figures shift with material costs, labor rates, and your specific installer’s overhead. Getting two or three itemized quotes at your estimated system size is still the most reliable way to confirm the number before committing.
Frequently asked questions
How do I know what size solar system I need?
Start from your average monthly electric bill, not a target number of panels. A ₱5,000 bill points to roughly a 3kW system, ₱8,000 to roughly 5kW, and ₱12,000 to roughly 8kW. From there, an installer adjusts for your actual roof space and usage pattern.
Should I size my system to cover 100% of my bill?
Usually not. Net metering only credits exported power at roughly ₱5-7/kWh, well below the retail rate, so oversizing a system to chase 100% offset means a large share of that extra production gets sold back cheaply instead of saving you full retail value. Most homeowners get better returns sizing to cover 60-90% of usage.
What does a solar system cost at each bill-based size?
Installed grid-tied residential systems typically run ₱50,000-70,000 per kW in the Philippines. A system sized for a ₱8,000/month bill (roughly 5kW) lands around ₱250,000-350,000 installed, before any battery.
How much will solar actually save me each month?
It depends on your usage pattern, but a well-sized grid-tied system commonly cuts 60-90% off a comparable bill. On an ₱8,000 bill, that's roughly ₱4,800-7,200 in monthly savings, which is what drives the 3-to-7-year payback typical of grid-tied systems here.
Is it better to size by bill amount or by panel count?
Bill amount is the better starting point, since it's the number most homeowners actually know. Panel count is really just the output of that calculation — bill to kWh, kWh to kW, kW to panel count — so starting from panels first skips the step that actually matters: matching system size to what you spend and use.
What if my bill varies a lot month to month?
Use your average over the past 6-12 months, including high-usage months (aircon season) and low ones, rather than your single highest or lowest bill. That average is a more realistic base for sizing than picking one extreme month.