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Home›Construction›Solar Panel Savings Calculator

Solar Panel Savings Calculator

Rooftop solar ROI, payback period and lifetime savings

Quick Answer — Solar Panel Savings

The Solar Panel Savings Calculator is a free online construction tool that helps you rooftop solar roi, payback period and lifetime savings. Enter your values above for instant, accurate results — no signup required. All calculations run privately in your browser.

Standard Formula Updated 2026
₹
kW
₹
₹1,50,000
₹10,000₹2,00,00,000
₹/unit
Methodology
Free forever Data stays on your device Works offline (PWA) Verified formulas

Maintained by: Sagar Sahni, Calc Labz  |  Review: formula checks, worked examples, and periodic updates

Use with care: Finance and tax outputs are planning estimates only and should be checked against current rules.

Need a correction? Contact us with the calculator name and the issue you found.

Formula & Worked Example

The math behind the Solar Panel Savings Calculator

Mathematical Formula

Payback = \frac{System\;Cost - Subsidy}{Annual\;Savings}
Where: - **Annual generation** = System kW × 4.5 (avg daily sun hours) × 365 × 0.8 (efficiency) - **Annual savings** = Units generated × Electricity tariff rate - **Subsidy**: PM Surya Ghar scheme — ₹30,000/kW for first 2 kW, ₹18,000/kW for next 1 kW (max 3 kW) - **Lifetime** = 25 years with ~0.5% annual degradation.

Step-by-Step Worked Example

**3 kW system at ₹1,50,000**, tariff ₹8/unit: - Annual generation = 3 × 4.5 × 365 × 0.8 = **3,942 units** - Annual savings = 3,942 × ₹8 = **₹31,536** - Subsidy = ₹30K×2 + ₹18K×1 = **₹78,000** - Net cost = ₹72,000 → Payback = **~2.3 years**

Frequently Asked Questions

Common questions about the Solar Panel Savings Calculator

Is rooftop solar worth it in India in 2026?
Yes, with 3-5 year payback and 25-year panel life, ROI is 300-500%. Key factors: PM Surya Ghar subsidy covers 40-60% of cost for up to 3 kW, electricity tariffs keep rising (~5-8% annually), and net metering lets you sell excess power. A 3 kW system saves ₹25,000-₹35,000/year on electricity bills.
What is the PM Surya Ghar Yojana subsidy?
Under PM Surya Ghar (2024 scheme): ₹30,000/kW subsidy for first 2 kW, ₹18,000/kW for additional capacity up to 3 kW, total max subsidy ₹78,000. For a 3 kW system costing ₹1.5-1.8 Lakh, your net cost after subsidy is only ₹72,000-₹1,02,000. Available only for residential consumers with valid electricity connection.
How much roof space do I need for solar panels?
Approximately 100 sq ft per kW. A 3 kW system needs ~300 sq ft of shadow-free roof area. Panels should face south (in India) with a tilt angle equal to your latitude (20-30 degrees). East-west facing roofs generate 10-15% less power. Flat roofs are ideal with adjustable tilt mounting structures.
How many units does a 1 kW solar system generate?
A 1 kW system generates approximately 4-5 units (kWh) per day or 1,200-1,500 units/year in most Indian cities. Peak output occurs 10 AM - 3 PM. Generation varies by region: Rajasthan/Gujarat get 5+ units/kW/day, while Kerala/Northeast get 3.5-4 units. Monsoon months see 30-40% lower output.
What maintenance does a rooftop solar system need?
Minimal maintenance: Clean panels with water every 2-4 weeks (dusty areas weekly), check wiring connections annually, and monitor inverter for errors. No moving parts to replace. Panels have 25-year warranty, inverters 5-10 years. Annual maintenance cost: ₹2,000-₹5,000. Panel degradation is only 0.5-0.7% per year.

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What is the Solar Panel Savings Calculator?

The Solar Panel Savings Calculator is a free online construction tool that helps you rooftop solar roi, payback period and lifetime savings. Built for accuracy and speed, this calculator uses verified formulas and provides instant results without requiring any signup or registration. All calculations run entirely in your browser, ensuring complete privacy — no personal data is ever sent to our servers.

How to Use the Solar Panel Savings Calculator

  1. Enter Current Monthly Electricity Bill: Enter your current monthly electricity bill in Indian Rupees (₹) in the input field. The calculator will validate your input automatically.
  2. Enter Solar System Size: Enter your solar system size (in kW) in the input field. The calculator will validate your input automatically.
  3. Enter Installation Cost: Enter your installation cost in Indian Rupees (₹) in the input field. The calculator will validate your input automatically.
  4. Enter Electricity Tariff: Enter your electricity tariff (in /unit) in Indian Rupees (₹) in the input field. The calculator will validate your input automatically.
  5. View Your Results: The Solar Panel Savings Calculator displays your results instantly in the output panel. You will see the primary result along with a detailed breakdown of secondary outputs. Scroll down for charts, interpretations, and expert advice.

Key Features

  • Instant Solar Panel Savings calculations with real-time updates
  • No signup, no registration — 100% free forever
  • All calculations happen in your browser — zero data sent to servers
  • Works offline as a Progressive Web App (PWA)
  • Mobile-friendly responsive design
  • Verified construction formulas updated for 2026

Why Use Calc Labz Solar Panel Savings Calculator?

The Calc Labz Solar Panel Savings Calculator stands out because it combines accuracy with simplicity. Unlike other online calculators, we provide detailed breakdowns, step-by-step formulas, and actionable advice alongside your results. Our construction calculators are regularly updated to reflect current rates, rules, and standards for India (2026). Whether you are a student, professional, or just need a quick calculation — Calc Labz delivers reliable results instantly.

Key Terms & Glossary

Concrete Mix Ratio
The proportion of cement, sand, and aggregate (e.g., M20 = 1:1.5:3) that determines concrete strength.
Stamp Duty
A state government tax levied on property registration, calculated as a percentage of property value.
Carpet Area
The usable floor area of a property, excluding walls, balcony, and common spaces.
Built-up Area
Carpet area plus the thickness of inner and outer walls — larger than carpet area.

Sources & References

Our Solar Panel Savings Calculator uses formulas and guidelines from the following authoritative sources:

  • PM Surya Ghar Muft Bijli Yojana
  • MNRE — Solar Rooftop Calculator