Calculate your true solar loan cost including dealer fees, federal tax credits, and 25-year electricity savings. Compare loan terms instantly — no sign-up required.
Understanding the true financial picture of a solar loan is one of the most important things a solar professional can do for a customer. Most simple calculators only show monthly payments — but the real question is: does this loan actually save money over time?
Our Solar Loan Calculator goes beyond monthly payment math. It factors in dealer fees (which lenders roll into the principal), the federal Investment Tax Credit (ITC), annual utility rate escalation, and 25-year panel degradation to give you a complete financial picture — monthly payment, effective APR, total interest paid, and net savings.
Whether you're helping a homeowner compare loan terms or doing a cash vs. finance analysis, this tool gives you the numbers you need in seconds.
True Cost Analysis
Calculates real loan cost including dealer fees that lenders embed in the principal, giving you the actual amount financed.
Tax Credit Integration
Applies the federal ITC (currently 30%) to reduce effective system cost and recalculate break-even timelines.
25-Year Savings Projection
Projects electricity savings year-by-year with utility rate escalation and panel degradation to show net lifetime value.
Comparing Loan Offers
Run multiple scenarios side-by-side to show customers the real difference between a 1.99% and 5.99% solar loan over 25 years.
Presenting to Homeowners
Generate a professional financial summary showing monthly savings, break-even point, and 25-year net benefit to close the deal.
Cash vs. Finance Analysis
Compare the financial outcome of paying cash vs. financing to match the homeowner's goals and capital position.
Enter System Cost
Input the total installed system cost before any credits or incentives. This is the gross contract price the customer sees on the proposal.
Set Dealer Fee %
Most solar lenders charge a dealer fee (1%–30%) rolled into the loan principal. This is the biggest hidden cost in solar loans — enter your lender's exact fee.
Enter Loan Terms
Input your APR and loan term in years. Common solar loan terms are 12, 20, and 25 years.
Apply Tax Credit
Enter the federal ITC percentage (currently 30% for 2025). The calculator shows both pre- and post-ITC monthly payments.
Set Utility Details
Enter the customer's current monthly bill, local electricity rate ($/kWh), and expected utility rate escalation (historically 2.9%/year).
Review Full Financial Picture
See monthly payment, effective APR after dealer fee, total interest paid, break-even month, and 25-year net savings all at once.
Monthly Payment
e.g. $187
Fixed monthly loan payment including dealer fee. This is what appears on the loan agreement.
Effective APR
e.g. 6.4%
True rate after dealer fees. A 1.99% loan with 25% dealer fee may have an effective APR of 6–8%.
Total Interest Paid
e.g. $8,420
Cumulative interest over the full loan term. Compare to 25-year savings to verify the loan is positive.
Net 25-Year Savings
e.g. $31,200
Total electricity savings minus total loan payments. A positive number means the loan saves money.
Break-Even Month
e.g. Month 94
When cumulative savings exceed cumulative payments. The homeowner enters positive cash flow here.
Loan payments are calculated using standard amortization formulas used by financial institutions. Energy savings projections factor in utility rate inflation and solar panel performance degradation to estimate long-term financial outcomes.
Standard fixed-rate loan amortization formula used for mortgages and solar financing.
Reflects the true financing cost after dealer fees and payment structure are included.
Utility rate inflation assumed at 2.9% annually. Solar production declines 0.5% per year.
Compares lifetime electricity savings against total financing cost.
Utility escalation reflects long-term EIA historical averages. Panel degradation reflects modern monocrystalline PERC module performance.
Use the calculator above for your specific loan details and utility rates.
| Loan Term | APR | Dealer Fee | Monthly Payment | Total Interest | Net 25-Yr Savings |
|---|---|---|---|---|---|
| 12 years | 5.99% | 0% | $333 | $7,870 | $28,500 |
| 20 years | 2.99% | 25% | $249 | $22,600 | $19,800 |
| 20 years | 5.99% | 0% | $221 | $23,040 | $18,400 |
| 25 years | 1.99% | 30% | $181 | $24,400 | $17,100 |
| 25 years | 5.99% | 0% | $193 | $27,900 | $13,500 |
| 25 years | 7.99% | 0% | $231 | $39,300 | $2,100 |
Based on $30,000 system, $150/month utility bill, $0.14/kWh rate, 4.5 peak sun hours/day, 80% efficiency.
Always Ask for the Dealer Fee
A 25% dealer fee on a $30,000 system adds $7,500 to the principal — raising the effective APR dramatically even on "low-rate" loans.
Compare Effective APR, Not Advertised APR
A loan at 1.99% with a 30% dealer fee has an effective APR of roughly 7–9%. Always calculate effective APR before presenting to customers.
Time the ITC Correctly
The homeowner must have sufficient tax liability to use the 30% ITC in one year. Unused ITC carries forward and changes the effective payback period.
Use Break-Even Month in Sales
"After month 94, every dollar you save on electricity is pure profit." This is more compelling than showing abstract 25-year totals.
A dealer fee (also called a "loan origination fee" or "bank fee") is a percentage of the system cost that the lender charges to offer a low advertised APR. The fee is added to the loan principal — so you finance more than the system costs. Common dealer fees range from 10% to 30%. Always ask your lender for the exact dealer fee before quoting a customer.
The ITC gives homeowners a dollar-for-dollar reduction in their federal income tax bill equal to 30% of the system cost. Many solar loans are structured so the homeowner makes minimum payments for the first 18 months, then applies the ITC refund to reduce the principal. Our calculator shows both the full-term payment and the post-ITC scenario.
APR is the advertised interest rate on the loan. Effective APR accounts for all fees — specifically dealer fees — to show the true cost of borrowing. A 2.99% APR loan with a 25% dealer fee may have an effective APR of 7–9%. Always use effective APR when comparing loans from different lenders.
It depends. A HELOC typically has no dealer fee and interest may be tax-deductible, but uses your home as collateral and has a variable rate. Solar-specific loans have fixed rates and no collateral requirement but often carry dealer fees. Use this calculator to compare both scenarios using actual lender terms.
Shorter terms (10–12 years) minimize total interest paid. Longer terms (20–25 years) reduce monthly payments for cash-flow-tight homeowners. The key is ensuring the monthly loan payment is less than the monthly electricity savings — so the homeowner saves money from day one.
Projections are accurate to within 10–15% for most U.S. markets. They use a 2.9% annual utility rate escalation (EIA historical average) and 0.5%/year panel degradation. Actual savings depend on local utility rate changes, actual energy production, and system maintenance.
It works for any amortizing loan structure. For commercial projects, also account for depreciation (MACRS), higher demand charges, and time-of-use billing — which can significantly increase savings and improve the effective payback period.
.svg)
