The Simple Formula
Calculating the payback period for your solar panels involves two key steps:
- Subtract any incentives or rebates you qualify for from the total installation cost.
- Divide the remaining cost by your annual savings on electricity bills.
The result is the number of years it will take to recoup your investment.
Step-by-Step Formula:
- Total Installation Cost – Incentives & Rebates = Net Investment
- Net Investment ÷ Annual Electricity Savings = Payback Period
For ROI, use the inverse: Annual Electricity Savings ÷ Net Investment = ROI percentage.
Key Factors for Southeastern PA Homeowners
1. Your Electricity Usage and PECO Rates
Start by calculating how much electricity you consume each month. With PECO currently charging approximately $0.22/kWh, the average Southeastern PA household spends $2,500-$4,000+ per year on electricity. PECO rates have risen consistently — typically 3-5% annually — which means your savings increase every year as rates go up while your solar cost stays fixed at $0.
2. Total System Cost
To calculate the total system cost, determine the size of the system you need based on your annual electricity usage. In Southeastern PA, solar systems typically cost between $2.50 - $3.00 per watt. A typical 10 kW residential system averages about $26,500 before incentives.
3. PA Solar Incentives
Two key incentives improve your payback in Pennsylvania:
- 1:1 Net Metering: PECO credits you at the full retail rate for excess electricity sent back to the grid, reducing your future bills and accelerating payback.
- Solar Renewable Energy Credits (SRECs): Earn approximately $250-$350+ per year in additional income from SRECs, which directly reduces your effective payback period.
4. Panel Efficiency Over Time
Modern solar panels maintain at least 85% efficiency after 25 years. At Pennstar Solar, we install exclusively Tier 1 panels with 25-year manufacturer warranties, ensuring your production — and savings — remain strong for decades.
What's a Good Payback Period?
Solar panels typically last 25+ years with proper maintenance. In Southeastern PA, the typical payback period is 8 to 10 years after factoring in PECO bill savings, SREC income, and net metering credits. That leaves 15-20+ years of pure profit — tax-free electricity savings that flow directly to your household budget.
Want to see the exact payback numbers for your home? Get a free savings estimate from Pennstar Solar or call 610-900-6405.