Today, I’m going to show you something most solar companies never bother to do: the actual math.
No vague promises. No “you could save up to X%” marketing language. Just real numbers, step by step, that you can replicate with your own bill right now.
This is called the Solar ROI Calculation — and once you see it, you’ll understand exactly why solar is one of the highest-return investments a Philippine homeowner or business owner can make today.
Step 1: Know Your System Size (kWp)
The first thing we determine is how large a system you need. System size is measured in kilowatt-peak (kWp) — the maximum power output your panels can produce under ideal conditions. The right system size is based primarily on your monthly electricity consumption.
📊 System Size Guide (Based on Monthly Bill)
Monthly Bill ₱2,500–₱3,500 → 3 kWp system
Monthly Bill ₱4,000–₱6,000 → 5 kWp system
Monthly Bill ₱6,000–₱9,000 → 8 kWp system
Monthly Bill ₱8,000–₱13,000 → 10 kWp system
Monthly Bill ₱12,000–₱20,000 → 15 kWp system
Monthly Bill ₱16,000–₱28,000 → 20 kWp system
Step 2: Calculate Daily and Monthly Production
The Philippines averages 4 peak sun hours per day — this is the number of hours the sun is intense enough to produce full-rated power from your panels. The formula is simple:
Example: 10 kWp × 4 hours = 40 kWh per dayMonthly Production (kWh) = Daily Production × 30 days
Example: 40 kWh × 30 = 1,200 kWh per month
Step 3: Calculate Your Monthly Savings in Pesos
Now multiply your monthly production by the current Meralco rate (₱13.82/kWh as of March 2026):
Example: 1,200 kWh × ₱13.82 = ₱16,584/month
Rounded to nearest ₱1,000 = ₱17,000 estimated monthly savings
Step 4: Calculate Your Annual Savings
Example: ₱17,000 × 12 = ₱204,000 per year
Step 5: Calculate Your Payback Period (ROI)
This is the big number — how many years until your solar system pays for itself completely, after which every peso of savings is pure profit:
Example (10kWp Solis On-Grid): ₱415,000 ÷ ₱204,000 = 2.03 years
Example (10kWp Huawei Premium): ₱520,000 ÷ ₱204,000 = 2.55 years
The 25-Year Picture
Solar panels carry a 25-year performance warranty. After payback, your system continues producing free electricity for the remaining years of its life. Let’s see what that looks like:
💰 25-Year Savings Projection (10kWp System, ₱13,000/month bill)
System cost: ₱415,000 (Solis On-Grid)
Annual savings: ₱204,000
Payback: ~2 years
Remaining productive years: 23 years
23 years × ₱204,000 = ₱4,692,000 in NET savings after payback
Total gross savings over 25 years: over ₱5.1 million. Not a typo.
Try It With Your Own Bill
We’ve built a free online calculator that does all of this math automatically — just enter your monthly bill and it shows you your recommended system size, estimated monthly savings, payback period, and 25-year savings total.
👉 Solar Savings ROI Calculator: www.solarhomeph.com/solar-savings-roi-calculator/
But I want to be honest with you: the calculator gives you a good estimate, but the most accurate numbers come from a FREE site assessment. Our engineers look at your actual bills (not just the total — but the actual kWh consumption), your roof orientation, shading from nearby buildings or trees, and your specific electrical setup. The result is a proposal that’s precise to within a few thousand pesos, not a rough estimate.
Want precise numbers tailored to your specific property? Reply to this email with your monthly bill amount and we’ll give you a preliminary estimate within 24 hours — then schedule your free on-site assessment at no cost.
In the next email, I’ll tackle one of the most common points of confusion in the solar world: the difference between On-Grid and Hybrid systems — and how to know which one is right for your situation.