Plug-In Solar Savings & Payback Calculator
Estimate how much a balcony solar kit could save you per year — and how fast it pays for itself — based on your state's electricity price.
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How the math works
The calculator uses a simple, transparent model: yearly production = system watts × production-per-watt, then yearly savings = production × your electricity rate, and payback = kit price ÷ yearly savings. We default to 1.0 kWh per watt per year, a reasonable middle estimate for a decently-placed panel; lower it toward 0.8 for shaded or vertical balcony mounts, or raise it toward 1.2–1.3 for sunny, tilted, south-facing installs.
The single biggest lever is your electricity rate — which is why the same kit pays back roughly three times faster in Hawaii or California than in Washington or Utah. Use our best kits guide to pick a system, then check the rules in your state before buying.