SolarEnergyPH
Solar Guide — Philippines
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Article 2 — Day 2
How to Choose the Right Solar System Size for Your Home
Subject: How to Choose the Right Solar System Size for Your Home
Preview: The simple bill-to-kW formula every Filipino homeowner should know.

How to Choose the Right Solar System Size for Your Home

The #1 mistake homeowners make? Installing a system that's too small — or overpaying for one that's too big.

The Bill-to-kW Formula

Your monthly bill ÷ ₱1,500 = recommended system size in kW

Monthly Meralco BillSystem SizePanels NeededEstimated Cost
₱3,0002 kW~4 panels₱120,000 - ₱160,000
₱5,0003 kW~6 panels₱180,000 - ₱230,000
₱8,0005 kW~10 panels₱280,000 - ₱350,000
₱12,0008 kW~16 panels₱400,000 - ₱500,000
₱15,00010 kW~20 panels₱500,000 - ₱620,000
₱20,000+12-16 kW~22-27 panels₱600,000 - ₱900,000

Prices based on 2026 Philippine market rates with installation.

Why This Formula Works

At ₱11/kWh (average Meralco rate), a 1kW solar system produces roughly ₱1,350-₱1,650 worth of electricity per month in the Philippines (based on 4.5 peak sun hours/day).

So dividing your bill by ₱1,500 gives you the sweet spot — enough solar to offset 80-90% of your consumption.

Factors That Affect Your System Size

Roof space — Each 550W panel is about 2.3m x 1.1m. A 5kW system needs roughly 25-30 sq.m. of unshaded roof space.

Roof direction — South-facing roofs in the Philippines get the most sunlight. East/west roofs lose about 10-15% production.

Shading — Trees, nearby buildings, or water tanks casting shadows on your panels can reduce output by 20-40%.

Future electricity needs — Planning to add an aircon or EV charger? Size up by 1-2 kW now. It's cheaper than adding panels later.

Grid-Tied vs. Hybrid Affects Cost

Type5kW System CostIncludes Battery?
Grid-Tied₱180,000 - ₱230,000No
Hybrid₱280,000 - ₱350,000Yes (4.8-5.12 kWh)

Don't Oversize

A common sales tactic: installers push a 10kW system on someone with a ₱5,000 bill. You'll produce way more than you consume, and the net metering credit rate is lower than the retail rate — so you lose money on the excess.

Rule of thumb: Size your system to cover 80-90% of your consumption, not 100%.

Try It Yourself

Use our free Solar Quotation Tool to select your system size, choose from 15+ panel and inverter brands, and see the full Bill of Materials with pricing. Takes less than 2 minutes.

Engr. Jason Morales — Founder, SolarEnergyPH

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