Understanding Our Solar Calculators

A complete guide to Solar Scout's four planning tools — how each calculator works, what to enter, and how to read your results.

Overview

Solar Scout Philippines provides four free planning calculators to help homeowners and businesses understand their solar potential before committing to an installation. The calculators work best in sequence: start with the Appliance Load Calculator to build an accurate consumption baseline, use the ROI Calculator for your system estimate, verify savings with the Bill Calculator, and decide on net metering last.

• ROI Calculator — How big a system do I need and when will it pay for itself?

• Appliance Load Calculator — How much electricity do my appliances actually consume?

• Solar Savings Bill Calculator — Which parts of my Meralco bill can solar eliminate?

• Net Metering vs Zero-Export — Is applying for net metering worth the cost and wait?

1. ROI Calculator

Get an instant solar estimate by entering a few details about your energy profile. The calculator outputs your recommended system size, payback period, monthly savings, and a 25-year projection — all updated in real time.

Step 1 — Set your average monthly electricity bill

Drag the slider or type a value between ₱1,000 and ₱50,000+. Use the amount from your most recent utility bill — this is the most critical input for accurate estimates. Check your bill's Amount Due field, or average the last 3 months for a more reliable baseline.

Step 2 — Choose your region / location

Select your utility provider from the dropdown (e.g., Metro Manila / Meralco). This determines the electricity rate per kWh used to calculate your savings — rates vary significantly by region. The exact rate and data date are shown at the bottom of the results panel.

Step 3 — Select your property type

Choose Residential for houses, condos, and townhouses, or Commercial for offices, shops, warehouses, and businesses. Commercial properties typically have higher consumption patterns, which affects system sizing and cost estimates.

Step 4 — Toggle optional add-ons

Check either or both options to see how they affect your blueprint. Results update instantly.

• Add a battery — Includes battery storage in the estimate. Useful for outage-prone areas or if you want energy independence after sunset.

• With net metering — Models excess solar sold back to the grid, improving your ROI and shortening the payback period for eligible properties.

Reading your Estimated Solar Blueprint

• System size (kWp) — Peak power your roof can generate at full sun. A higher monthly bill means a larger system is needed.

• Payback period — The number of years to recover your installation cost through savings. A Strong Estimate badge indicates high confidence.

• Monthly savings (₱) — Projected reduction off your monthly bill, shown in ₱ and as a percentage of your current spend.

• Estimated cost range (₱) — Covers panels, inverter, and installation. Actual installer quotes may vary.

• 25-year savings projection — Total projected net savings over the panel lifetime, accounting for annual rate increases and panel degradation of approximately 0.5% per year.

2. Appliance Load Calculator

Build a detailed picture of your home or business electricity consumption by listing your appliances. The calculator totals your daily and monthly load, then recommends the right solar system size and estimated cost — no electricity bill needed.

Step 1 — Select your region

Choose your utility provider from the Your Region dropdown. This sets the electricity rate used to calculate costs and carries over to the ROI Calculator when you're ready.

Step 2 — Add your appliances

Option A — Quick-Add: Click any pill from the Quick-Add Appliances section to instantly add a common household appliance with pre-filled wattage defaults:

• Air Conditioner (1HP) — 750 W

• Refrigerator — 150 W

• Washing Machine — 500 W

• Television (55") — 150 W

• Electric Fan — 60 W

• Rice Cooker — 700 W

• Microwave — 1,000 W

• Water Heater — 1,500 W

• Desktop PC — 200 W

• Laptop — 65 W

• LED Lights (per bulb) — 9 W

• Water Pump — 370 W

Option B — Add Custom Appliance: Click the Add Custom Appliance button to enter any appliance not on the list. Check the label on the back of the appliance for its rated wattage.

Step 3 — Adjust quantity and daily hours

For each appliance row, set two values:

• QTY — how many units you have (e.g., 6 LED bulbs)

• HRS/DAY — how many hours per day that appliance typically runs

For weekly appliances, convert to a daily average — for example, a washing machine used 3 times a week for 1 hour each equals 0.4 HRS/DAY (3 × 1 ÷ 7).

Reading your Load Profile

• Daily consumption (kWh/day) — Total energy all appliances consume in one day.

• Monthly consumption (kWh) — Daily consumption × 30 days, approximating what appears on your monthly electricity bill.

• Recommended system (kWp) — System size = Daily load ÷ (Peak Sun Hours × 0.80 derating). The derating accounts for real-world losses from heat, wiring, and inverter conversion.

• Estimated cost (₱) — A ballpark installation cost based on the recommended system size, covering panels, inverter, and standard installation.

Once your load profile looks accurate, click Estimate ROI from This Load to carry your results directly into the ROI Calculator.

3. Solar Savings Bill Calculator

See exactly what your Meralco bill is made of — and how much of it solar can eliminate. Enter your monthly bill amount and the calculator breaks it down line by line, showing which charges solar offsets and which ones remain regardless.

Step 1 — Enter your total monthly bill

Drag the slider or type your bill amount between ₱500 and ₱30,000+. Use the Total Amount Due from your latest Meralco billing statement.

Step 2 — Enter your monthly consumption (optional)

If your billing stub shows your kWh for the month, enter it in the Monthly Consumption field. If left blank, the calculator estimates your usage using a partial blended-rate model. Entering the actual figure produces a more accurate breakdown. You can find your monthly kWh on your Meralco bill under Current kWh or Consumption.

Important: Meralco rates change monthly. This breakdown uses the most recently available rates. Treat all figures as planning estimates — not official bill replicas. Always confirm with your actual billing statement.

Current bill tab — Modeled Current Bill

Shows your estimated bill broken down into individual charge components before any solar is applied. Blue dots indicate solar-reducible charges. Gray dots indicate fixed charges that remain regardless of solar.

Solar-reducible charges (blue dots):

• Generation Charge — the cost of producing the electricity

• Transmission Charge — the cost of moving electricity from plants to the grid

• System Loss Charge — energy lost during transmission and distribution

• VAT on gen, trans, and SL — 12% VAT applied to the three charges above

Fixed charges that remain (gray dots):

• Distribution Charge — Meralco's cost to deliver power to your home

• Subsidies / Cross-subsidy — government lifeline subsidies, shown as a deduction

• Universal Charge — national fund for missionary electrification

• Other Charges — miscellaneous regulatory and pass-through fees

• Meter / Customer Charge — fixed monthly fee for the meter and account

With solar tab — Modeled Bill With Solar

• Offset by Solar — the portion of your bill, in ₱ and percentage, that solar generation can eliminate.

• Remains Regardless — fixed charges that persist even with full solar coverage, shown in ₱ and percentage. This is the minimum you will pay even after going solar — factor this into your savings expectations.

4. Net Metering vs Zero-Export Calculator

Decide whether applying for net metering is worth it for your setup. Enter your generation profile and the calculator tells you how much your excess solar is worth, how long it takes to break even on the application fee, and whether net metering makes financial sense given your approval wait time.

Background: Net metering vs zero-export

Zero-export means your system only powers your home. Excess generation is unused or throttled and no application is needed.

Net metering means excess generation is exported to the grid. Your utility issues generation credits in ₱/kWh that offset future bills. This requires a formal application and approval from your distribution utility. Net metering is generally more efficient financially, but it comes with an application fee and a waiting period. This calculator helps you decide if the credits justify the cost and delay.

Step 1 — Set your daily excess generation

Drag the slider between 0.5 kWh and 20 kWh to set how much solar energy your system exports to the grid per day — the surplus after your home has consumed what it needs. You can estimate this by subtracting your daily household consumption from your system's daily output.

Step 2 — Set your self-consumption ratio

This slider represents the percentage of your solar generation your household uses directly before any excess is exported.

• 10% (exports most) — most of your solar goes to the grid, common for small households or large systems

• 100% (zero-export) — your home consumes everything your panels produce, nothing is exported

A typical household with moderate daytime usage falls between 60% and 85%.

Step 3 — Set the expected approval delay

Drag the slider from 1 to 12 months to reflect how long you expect your distribution utility to take to approve your net metering application. Timelines vary by utility and region — ask your solar installer for a realistic estimate in your area.

Step 4 — Enter the application fee

Pre-filled with the standard residential default of ₱3,000. Update this if your distribution utility charges a different amount.

Step 5 — Enter the generation credit rate

Pre-filled with the blended ₱/kWh rate your distribution utility pays for exported electricity. This rate is typically lower than the retail rate on your bill. Update it if you know your utility's current published rate.

Reading the Net Metering Analysis

• Recommendation — a direct verdict to apply or stay on zero-export, with a one-line rationale based on your inputs.

• Monthly Export Value (₱) — the ₱ value of excess electricity you export to the grid each month at the generation credit rate.

• Cost of Delay (₱) — total export credits forfeited during the approval waiting period.

• Fee Breakeven — number of months of export credits needed to recover the application fee alone.

• Total Justify Time — combined time to recover both the application fee and the credits lost during the approval delay.

Tips

• Apply for net metering as soon as your system is installed — credits do not accrue during the waiting period.

• If your self-consumption ratio is close to 100%, your export volume may be too low for net metering to be financially worthwhile.

• Generation credit rates are updated periodically by your distribution utility. Check for the latest published rate before making a final decision.

Understanding Our Solar Calculators