Solar Loan Payment Calculator (2026)
Type in the price, rate and term from your own quote and see the monthly payment, the total interest and what the financing really costs compared with paying cash. We are not a lender: every rate and fee on this page is an example you change.
Short answer
A solar loan payment depends on four things: the amount you borrow, the interest rate, the number of years and any fee added to the balance. The calculator does that arithmetic with the numbers you enter, and nothing else.
Two things are easy to miss. First, the interest rate is not the whole cost: a 2024 US Consumer Financial Protection Bureau (CFPB) study found that many solar loans carry a dealer or program fee, described as about 10% to 30% of the cash price, built into the financed price rather than shown on its own. That is why the calculator asks for the cash price and the price on the loan quote separately. Second, buying no longer earns the 30% federal homeowner credit, so the loan has to be repaid from your savings alone.
Enter your quote below. Then see how the term and the rate change the result.
Calculating... per month
| Your loan | Amount |
|---|
Same loan, different terms
Same price, rate, down payment and fee. Only the number of years changes.
| Term | Monthly payment | Total interest | Total repaid |
|---|
Same loan, different rates
Two points either side of the rate you entered, so you can see how much the rate on your quote matters.
| Rate | Monthly payment | Total interest | Total repaid |
|---|
What you still owe along the way
The balance left after the payments in each year, if you pay on schedule. It matters if you sell the house or pay the loan off early.
| After | Balance still owed |
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Planning arithmetic only. Not a loan offer, a quote, tax advice or a credit decision. SolarNiverse is not a lender. Your lender's written terms decide your real payment. How this is calculated.
What changes a solar loan payment
- The balance. Price minus down payment, plus any fee added to the loan. A fee of 5% adds 5% to the balance and to every payment.
- The financed price. If the loan quote is higher than the cash price, you pay that difference as part of the loan and pay interest on it too.
- The rate. A lower rate lowers the payment, but a low stated rate can come with a higher financed price, so compare the total repaid, not only the rate.
- The term. A longer term lowers the payment and raises the total interest. Some loans allow extra payments with no penalty; ask.
Ask for two prices. Ask the installer for the cash price and the loan price, in writing, on the same day. The CFPB found that a fee is often built into the loan price and left out of the stated rate. If the two prices match, say so in the first box; if they differ, the calculator treats the gap as a cost of financing.
The federal credit and your loan
The Section 25D homeowner credit is not allowed for expenditures made after December 31, 2025. For solar, an expenditure counts as made when the installation is finished, so paying earlier does not help if the system is completed later. This calculator therefore counts no federal credit for a purchase paid with cash or a loan. Some states have their own credits for systems you own; the box above takes whatever amount you expect, and it only affects the net cost line, never the loan.
A loan that is not secured by your home normally gives no interest deduction. Interest on a home equity loan or line of credit is deductible only if you itemize and the money buys, builds or substantially improves the home that secures it (IRS Publication 936). Whether that fits a solar project is a question for a tax professional.
If you are weighing other ways to pay, see the lease vs buy calculator, the home equity calculator and the financing options guide.
How the calculator works
It uses the standard level-payment formula for an amortizing loan, with interest charged monthly at one twelfth of the yearly rate. The balance is the price on the loan quote (or the cash price if you leave it blank), minus the down payment, plus the fee as a percentage of the amount borrowed. Total interest is the payments added up minus the balance. The balance still owed after any year is calculated in closed form and checked in our tests against a month-by-month simulation.
- Extra vs cash price is everything you pay in total (down payment plus every payment) minus the cash price: interest, fee and any financed-price difference together.
- Savings line is your monthly bill savings minus the payment. It is a planning comparison using the savings you type in; savings change with your usage, your utility's prices and rules, and the system's output.
- The calculator does not know about your credit, your lender's fees (such as appraisal or closing costs on a home-secured loan), prepayment penalties, taxes, or any rate that changes over time. Variable-rate loans need a different calculation.
Before you sign, ask for: the cash price and the loan price, the interest rate and the annual percentage rate (APR), every fee and who it is paid to, whether the rate or payment can change, whether you can prepay without a penalty, whether the loan is secured by your home or the equipment (a lien), and what happens to the loan if the installer or lender closes or the loan is sold to another company.
Frequently asked questions
How is a solar loan payment calculated?
The standard amortizing-loan formula: the amount borrowed, the interest rate per month and the number of monthly payments give one level payment. A higher rate, a longer term or a larger balance changes it. The calculator uses exactly this formula with the numbers you enter.
What interest rate should I enter?
The one on your written loan quote. We do not publish current solar loan rates because we are not a lender and we have not verified a representative 2026 rate. The rate field starts with an example value only; replace it with your quote, and try a few rates to see how much the payment moves.
Why can a solar loan cost more than the cash price plus interest?
The CFPB found in 2024 that many solar loans include a dealer or program fee, which it described as roughly 10% to 30% of the cash price, built into the financed price instead of shown separately. Ask for the cash price and the financed price in writing, and enter both in the calculator to see the difference.
Is there a federal tax credit for a solar loan in 2026?
Not for homeowners who buy their system. The Section 25D credit is not allowed for expenditures made after December 31, 2025, and for solar that means installation completed after that date. The calculator therefore counts no federal credit. If you expect a state or local incentive, you can enter it as a separate amount.
Is a longer loan term better?
A longer term lowers the monthly payment but increases the total interest. The comparison table shows both for the same loan at 10, 12, 15, 20 and 25 years.
Is the interest on a solar loan tax deductible?
Usually not for an ordinary solar loan. Interest on a loan secured by your home, such as a home equity loan or line of credit, is deductible only if you itemize and the money is used to buy, build or substantially improve that home, under IRS Publication 936. Ask a tax professional about your situation.
Are the figures on this page a loan offer?
No. SolarNiverse is not a lender, does not make or arrange loans, and does not check your credit. The results are arithmetic on the numbers you type in.
- CFPB, Issue Spotlight: Solar Financing (August 2024): fees built into the financed price, 10% to 30% of the cash price
- IRS FAQ on Public Law 119-21 (Section 25D: no credit for expenditures after Dec 31, 2025)
- Public Law 119-21 (the 2025 law), text
- IRS Publication 936: home mortgage interest deduction, including home equity debt
Related: Solar lease vs buy calculator · Solar ROI calculator · Solar incentives by state