Balcony Solar ROI Calculator

Plug in your balcony kit cost, annual output, self-consumption, and tariffs to see how fast the system pays back and what the lifetime savings look like after panel degradation, exported energy credits, and maintenance.

Upfront price of the plug-and-play kit including inverter and mounting.
Energy yield expected per year for your orientation and latitude.
Share of production you consume instantly behind the meter (self-consumption).
Price you pay for electricity from the grid.
Optional. Default $0.05/kWh received for exported energy.
Optional. Default 0.80% yearly output loss.
Optional. Default 20-year analysis window.
Optional. Default $0 — include inspection or cleaning costs.

Regulatory caps on balcony systems vary by country. Confirm legal limits and grid registration requirements before purchase.

Examples

  • $1,000 kit, 600 kWh/year, 75% self-consumption, $0.28 retail, $0.10 export ⇒ Self-consumption 75.00% (450.00 kWh on-site, 150.00 kWh exported). First-year savings: $275.00 • Payback: 3.6 years • Lifetime savings (20 y): $4,813.47 • Net gain after cost: $3,813.47.
  • System cost $950, 600 kWh/year, 60% self-consumption, $0.30 retail, $0.05 export, 0.8% degradation, 25-year horizon ⇒ Self-consumption 60.00% (360.00 kWh on-site, 240.00 kWh exported). First-year savings: $234.00 • Payback: 4.1 years • Lifetime savings (25 y): $5,224.32 • Net gain after cost: $4,274.32.

FAQ

How do subsidies affect the calculation?

Subtract grants or rebates from the installed cost before running the numbers so payback reflects your net outlay.

Can I model battery add-ons?

Yes—add the battery price to the installed cost and adjust self-consumption upward to reflect higher utilisation.

What export rate should I use?

Check your utility’s feed-in tariff or compensation scheme; if none applies, set the export credit to zero to be conservative.

Additional Information

  • Self-consumption determines how much of your production offsets the retail tariff. Increase it with timers, smart plugs, or small batteries.
  • Degradation models the gradual decline in panel output. Balcony modules often lose 0.5–1.0% per year.
  • Include maintenance for safety inspections, inverter swaps, or mandated grid inspections in some EU countries.

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