Solar Panel Payback & Net Metering Savings Estimator
Calculate solar panel system size, upfront cost after subsidies, payback period, and 25-year electricity savings.
Solar Panel Payback & Net Metering Savings Estimator
Calculate rooftop solar system size, subsidy discounts, break-even payback period, and 25-year net savings.
⚙️ Electricity Bill & Installation Inputs
☀️ System Financial Summary
What is the Solar Panel Payback & Net Metering Savings Estimator?
The Solar Panel Payback & Net Metering Savings Estimator helps homeowners and commercial property owners calculate the return on investment (ROI) of installing rooftop solar panels.
Targeted for both India (PM Surya Ghar 300 Units Scheme) and Global / US markets (30% Residential Clean Energy Credit):
- Recommended System Size (kW): Based on monthly power bill and peak sun hours (avg 4.5 hrs/day).
- Government Subsidy Subtractions: Calculates subsidy deductions (e.g. ₹78,000 / $1,000 max subsidy).
- Payback Period: Computes the exact years to break even on net installation cost.
- 25-Year Net Lifetime Savings: Total electricity bills saved over the 25-year manufacturer warranty period.
How Does the Solar Panel Payback & Net Metering Savings Estimator Work?
1. Enter Monthly Electricity Bill — Input average monthly power bill ($ or ₹).
2. Set Electricity Rate per Unit (kWh) — Input cost per unit of power (e.g. ₹8/kWh or $0.16/kWh).
3. Select System Size or Auto-Calculate — Choose 3 kW, 5 kW, 10 kW rooftop solar size.
4. Input Government Subsidy Amount — Deduct federal/state solar subsidies.
5. View Payback Period & 25-Year Savings — Instantly review break-even age, annual savings, and net lifetime ROI.
Formula & Calculation Method
1. Monthly & Annual kWh Consumption:
$$\text{Monthly kWh} = \frac{\text{Monthly Power Bill}}{\text{Rate per kWh}}$$
$$\text{Recommended kW Size} = \frac{\text{Monthly kWh}}{30 \text{ days} \times 4.5 \text{ peak sun hrs}}$$
2. Net Upfront Cost:
$$\text{Gross System Cost} = \text{kW Size} \times \text{Cost per kW}$$
$$\text{Net System Cost} = \text{Gross System Cost} - \text{Government Subsidy}$$
3. Payback Period & Lifetime ROI:
$$\text{Annual Savings} = \text{Monthly Bill Saved} \times 12$$
$$\text{Payback Period (Years)} = \frac{\text{Net System Cost}}{\text{Annual Savings}}$$
$$\text{25-Year Lifetime Net Savings} = (\text{Annual Savings} \times 25) - \text{Net System Cost}$$
Example Calculation
Example: Homeowner with ₹4,000 ($50) Monthly Bill (₹8 / kWh rate)
- Monthly Consumption: 500 units (kWh) → Recommended kW Size: ~3.7 kW
- Gross Installation Cost (3.7 kW @ ₹55,000/kW): ₹2,03,500
- PM Surya Ghar Subsidy Deduction: -₹78,000 → Net System Cost = ₹1,25,500
- Annual Electricity Savings: ₹4,000 × 12 = ₹48,000/year
Results:
- Payback Period: ₹1,25,500 ÷ ₹48,000 = 2.6 Years to Break-Even!
- 25-Year Net Savings: (₹48,000 × 25) - ₹1,25,500 = ₹10,74,500 Net Profit