The default solar loan estimates a $157.49 monthly payment. Estimate monthly solar-loan payments and compare them with an assumed reduction in your electricity bill. The 2026 scenario uses no federal residential solar credit; enter the full amount financed.
Key Model Assumptions & Benchmark Data
- Internal Revenue Service (IRS) & U.S. DOE (IRS FS-2025-05 (retrieved 2026-10-20)):Under IRS FS-2025-05 (Public Law 119-21), the IRC Section 25D credit is not allowed for any expenditures made after December 31, 2025 (2025-12-31); if installation is completed after December 31, 2025, the expenditure is treated as made after December 31, 2025. The 2026 calculator default is $0 federal credit.
- National Renewable Energy Laboratory (NREL) (NREL ATB 2024/2025 (retrieved 2026-10-20)):Reference for residential photovoltaic capital cost assumptions; the $22,000 gross system cost and 5.99% APR are illustrative calculator defaults.
Interactive Model & Inputs
Adjust variables below to instantly compute real-time projections and amortization.
Calculation Results & Payback Projections
How Solar Loan Payments Are Estimated
This model applies the loan rate and term to the gross installed system cost. It does not subtract an assumed federal credit: under IRS FS-2025-05 (Public Law 119-21), the Section 25D Residential Clean Energy Credit is not allowed for any expenditures made after December 31, 2025, and if installation is completed after December 31, 2025, the expenditure is treated as made after December 31, 2025, so the 2026 default is $0.
Some lenders offer re-amortization or bridge-payment structures, but their terms vary. Review the lender contract and model any verified state, local, or utility incentives separately; this calculator does not assume a tax refund or include personal tax advice.
The displayed 25-year scenario holds the estimated monthly bill offset constant. It does not model utility-rate escalation, panel degradation, maintenance, or incentives, so actual savings can differ.
Solar Loan Principal & Monthly Payment Formula
Loan Principal = Gross System Cost; Monthly Payment = Principal × [ r(1+r)^n ] / [ (1+r)^n - 1 ]The 2026 model uses the entered gross system cost as the loan principal. r is the monthly interest rate and n is the total loan term in months.
Worked example: understand your inputs
At these settings, the loan payment is $157.49 a month and the modeled monthly cash-flow difference is +$22.51. The 25-year difference between modeled bill savings and loan repayments is $16,203. The federal credit in this 2026 scenario is $0.
| Input | Example value | What to enter |
|---|---|---|
| System Cost | 22000 | Gross amount financed in dollars, including financed installation fees. |
| Interest Rate | 5.99 | Annual loan interest rate in percent. Compare the lender’s APR and fees separately. |
| Loan Term | 20 | Number of repayment years, converted to monthly payments. |
| Current Bill | 200 | Current monthly electricity bill in dollars. The model assumes a 90% bill offset. |
How to interpret the result
A positive monthly difference means the assumed bill savings exceed the payment; a negative result means an additional monthly expense. Cash-flow break-even and lifetime savings answer different questions.
What this estimate leaves out
The 25-year figure is undiscounted and excludes panel degradation, inverter replacement, maintenance, insurance, export-tariff changes and resale value. A 90% bill reduction is an assumption, not a production estimate. Obtain a roof-specific generation estimate and use the renewable break-even tool for eligible local incentives.
Financial Advantages of Going Solar with Financing
Immediate Utility Bill Offset
Lock in clean power generation at a fixed monthly cost that is frequently lower than your previous utility bill.
Model Gross Project Cost
See the loan payment based on the full system cost without an assumed federal credit or refund.
Hedge Against Utility Inflation
Shield your household from utility rate hikes, grid congestion fees, and carbon transition surcharges.
Customer-Owned Asset Flexibility
Customer-owned solar installations avoid third-party lease transfer restrictions when refinancing or selling a home.
Frequently Asked Questions
Does the federal Section 25D credit apply to a new 2026 installation?
No. Under IRS FS-2025-05, IRC Section 25D is not allowed for any expenditures made after December 31, 2025, and if installation is completed after December 31, 2025, the expenditure is treated as made after December 31, 2025. This calculator therefore uses a $0 federal credit for its 2026 default; consult the IRS or a qualified tax professional about a prior-year installation or your individual filing.
What is the typical payback period for a residential solar loan?
Without the expired federal Section 25D credit, unsubsidized residential solar simple payback typically ranges from 9 to 13 years (10.7 years in our default break-even scenario), depending on local solar irradiance, utility electricity rates, net billing rules, and state or utility rebates.
Do solar panels increase home property taxes?
In most U.S. states (including California, Texas, Florida, and New York), rooftop solar energy systems are explicitly exempt from local property tax assessments, meaning you gain home equity without higher property taxes.
What happens to my solar loan if I sell my home before payoff?
You have two options: use the proceeds from your home sale to pay off the remaining loan balance, or transfer the loan to the buyer if your lender and the buyer’s mortgage underwriter approve the credit transfer.
Authoritative Benchmark Sources & Active Incentives
IRS FS-2025-05: IRC Section 25D Residential Clean Energy Credit termination date (Internal Revenue Service (IRS) & U.S. DOE)
Under IRS FS-2025-05 (Public Law 119-21), the IRC Section 25D credit is not allowed for any expenditures made after December 31, 2025 (2025-12-31); if installation is completed after December 31, 2025, the expenditure is treated as made after December 31, 2025. The 2026 calculator default is $0 federal credit.
NREL Annual Technology Baseline (ATB) — Residential PV (National Renewable Energy Laboratory (NREL))
Reference for residential photovoltaic capital cost assumptions; the $22,000 gross system cost and 5.99% APR are illustrative calculator defaults.
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