Solar calculator
What could your roof generate — and save?
Clean Energy. Smarter Future.
Real-time estimates from your own bill and site. Every assumption is visible and editable below. Results are estimates, not a quotation or a guarantee.
Navya Solar — Solar Calculator summary · navyasolar.in · +91 85001 25888
Printed . Estimates only — not a quotation or performance guarantee.
Recommended system
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Panels
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Roof area needed
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Generation / month
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Savings / month (yr 1)
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Estimated new bill
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Bill offset
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Payback
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25-year net savings
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Where your solar energy goes (year 1)
- Self-consumed—
- Exported to grid—
- Still imported from grid—
- Annual generation—
- Annual consumption—
- Gross savings, year 1—
- CO₂ avoided / year—
Monthly bill
- Today
- With solar (est.)
System summary
- Estimated monthly usage—
- Size to match usage—
- Max size for your roof—
- Specific yield—
- Indicative system cost—
- 25-year gross savings—
Cumulative savings vs. system cost
- Annual savings
- Net position (savings − cost)
Year-by-year projection
| Year | Generation (kWh) | Tariff (₹/kWh) | Savings (₹) | Net position (₹) |
|---|
Methodology, formulas & assumptions
Consumption
Monthly usage (kWh) = (Bill − Fixed charges) ÷ Tariff — or your entered kWh
System size
Specific yield (kWh/kW/yr) = Peak sun hours × 365 × Performance ratio
Size to match usage (kW) = Annual usage ÷ Specific yield
Roof limit (kW) = Roof area ÷ Area per kW
Panels = ⌈ Size × 1000 ÷ Panel W ⌉ (⌊ ⌋ when the roof limits size)
System kW = Panels × Panel W ÷ 1000
Energy & savings (year 1)
Generation = System kW × Specific yield
Self-consumed = min(Generation × Self-use %, Usage)
Exported = Generation − Self-consumed; Imported = Usage − Self-consumed
Net metering: Savings = Tariff × (Self-consumed + min(Exported, Imported)) + Surplus rate × max(0, Exported − Imported)
Net billing: Savings = Tariff × Self-consumed + Export rate × Exported
New bill = Fixed charges + max(0, Usage × Tariff − Savings ÷ 12)
Multi-year projection
Generationₜ = Generation₁ × (1 − degradation)^(t−1)
Tariffₜ = Tariff × (1 + escalation)^(t−1); export rate held flat
Payback = first year cumulative savings ≥ system cost (interpolated)
- Results are estimates for planning. Actual output depends on shading, orientation, tilt, temperature, soiling, equipment and grid availability.
- Consumption is assumed constant; net-metering settlement is approximated annually (monthly/seasonal mismatch is not modelled).
- No government subsidy is assumed. Check current eligibility on pmsuryaghar.gov.in and use the ROI calculator to include one.
- Solar does not remove fixed or demand charges, so it does not always eliminate the bill.
- Maintenance and inverter replacement are not deducted here — the ROI calculator includes them.
This calculator provides indicative estimates only and is not a quotation, an offer or a performance guarantee. A site survey is required for an engineered design.