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Rooftop Solar Calculator — Tamil Nadu

Estimate yearly kWh and bill savings from a rooftop solar system in Tamil Nadu using local irradiance (5.4 kWh/m²/day) and tariffs.

How much will a rooftop solar system actually generate in Tamil Nadu? Tamil Nadu's low latitude (8–13°N) means flat panel tilts and a strong December–May season; TANGEDCO net-feed-in rules differ from net-metering states. This estimator starts from the long-term local irradiance (5.4 kWh/m²/day) and a realistic loss stack, then prices the energy at the local tariff (₹8/kWh, editable) — adjust tilt and soiling to match your roof.

8,845 kWh
Estimated annual production
1,769 kWh/kWp·yr
Specific yield
82%
Performance ratio
₹70,764
Annual bill value at your rate
Jan690 kWh
Feb725 kWh
Mar840 kWh
Apr867 kWh
May885 kWh
Jun752 kWh
Jul619 kWh
Aug601 kWh
Sep690 kWh
Oct752 kWh
Nov708 kWh
Dec716 kWh

With your numbers: 5 kW × 5.4 kWh/m²/day × 365 × 1.10 (plane-of-array) × 82% PR = 8,845 kWh/year. First-year figure — subtract ~0.5%/yr panel degradation for later years.

Sources: NREL PVWatts v8 model (POA irradiance × system losses); Global Solar Atlas — long-term GHI, India — Tamil Nadu

Indicative estimates only, not financial or investment advice. Tariffs, subsidies and net-metering rules change — verify with your DISCOM, utility or installer before committing.

Use the free Rooftop Solar Calculator — Tamil Nadu online — Estimate yearly kWh and bill savings from a rooftop solar system in Tamil Nadu using local irradiance (5.4 kWh/m²/day) and tariffs. Runs instantly in your browser: no signup, no upload, mobile-friendly.

About Rooftop Solar Calculator — Tamil Nadu

How much will a rooftop solar system actually generate in Tamil Nadu? Tamil Nadu's low latitude (8–13°N) means flat panel tilts and a strong December–May season; TANGEDCO net-feed-in rules differ from net-metering states. This estimator starts from the long-term local irradiance (5.4 kWh/m²/day) and a realistic loss stack, then prices the energy at the local tariff (₹8/kWh, editable) — adjust tilt and soiling to match your roof.

How to use Rooftop Solar Calculator — Tamil Nadu

  1. 1Enter your system size in kW (or keep the segment-typical default).
  2. 2Fine-tune irradiance, tilt and soiling to match your site — the help text gives local reference values.
  3. 3Read annual kWh, specific yield, PR and the monthly split; set your tariff to price the energy.

Why use Rooftop Solar Calculator — Tamil Nadu?

  • Region-true defaults: long-term irradiance, optimal tilt and local tariff are pre-loaded, not guessed
  • PVWatts-style physics — plane-of-array gain, full loss stack and performance ratio shown transparently
  • Month-by-month generation table exposes the seasonal shape, not just an annual headline
  • Everything computes instantly in your browser — no signup, no quote-form ambush

Frequently asked questions

How accurate is the Rooftop Solar Calculator — Tamil Nadu?+

It uses the same physics as NREL's PVWatts: irradiance × plane-of-array factor × performance ratio. With honest inputs, expect results within ±10% of a professional simulation — good enough for sizing and payback decisions. For bankable projects, follow up with site-measured data and a full TMY simulation.

What is specific yield and what's a good value?+

Specific yield is annual kWh produced per kW of panels. It removes system size from the comparison: 1,400–1,700 kWh/kWp is typical across sunny India, 950–1,100 in Germany or the UK. If a quote promises far above the regional norm, question the assumptions.

Why is my real output lower than the calculator says?+

The usual suspects in order: more shading than assumed, dust (soiling can cost 5–15% where cleaning is irregular), inverter undersizing/clipping, and higher cell temperatures than the default loss stack assumes. Compare measured monthly output against the table here to localize the gap.

Does panel direction matter as much as size?+

Orientation typically moves output 5–25%. Equator-facing at near-latitude tilt is ideal; east/west roofs lose roughly 10–20% but spread generation across the day, which can be worth more under time-of-use tariffs or self-consumption rules.

Embed Rooftop Solar Calculator — Tamil Nadu on your website

Want Rooftop Solar Calculator — Tamil Naduon your own site? Paste this snippet into any HTML page — it's free, with no API key or sign-up. The tool loads in an iframe and keeps working exactly as it does here.

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