Solar ROI Calculator

Calculate the return on investment for your solar system

Formulas:
Net Cost = Total System Cost - (Total System Cost × Tax Credit %) - Local Incentives
Payback Period = Net Cost / Annual Savings
25-Year Savings = Σ [Annual Savings × (1 + Rate Increase)^Year] for Years 1-25
ROI = ((25-Year Savings - Net Cost) / Net Cost) × 100%

System Size (kW):

Total System Cost ($):

Federal Tax Credit (%):

State/Local Incentives ($):

Average Monthly Electricity Bill ($):

Annual Electricity Rate Increase (%):

ROI Analysis

Tax Credit Amount: $0

Net Cost: $0

Annual Savings: $0

Payback Period: 0 years

25-Year Savings: $0

ROI: 0%

Example Calculation

For a 5kW system costing $14,000, with 30% tax credit, $1,000 local incentives, $150 monthly bill, and 3% rate increase:

Tax Credit Amount = $14,000 × 30% = $4,200

Net Cost = $14,000 - $4,200 - $1,000 = $8,800

Annual Savings = $150 × 12 = $1,800

Payback Period = $8,800 ÷ $1,800 = 4.9 years

25-Year Savings = $67,625 (calculated with compound annual increases)

ROI = (($67,625 - $8,800) ÷ $8,800) × 100% = 668%

This calculator is part of "The Ultimate DIY Solar Power System: The Complete A-Z Guide"