Financing
Enter your system price, APR, and term. See the full cost of financing with $0 down, then compare it against adding a down payment of your choice.
How it works
Step 1
Use the full cash price from your proposal, along with the APR and term your lender is offering. The loan payment calculator gives you just the zero-down monthly figure if that's all you need right now.
Step 2
Try a few different amounts to see how the monthly payment and total interest respond. Even a modest down payment can noticeably reduce what you pay over the loan's full term.
Step 3
Putting cash down only makes sense if you don't have a better use for it, like an emergency fund or a higher-return investment. The down payment impact on payback tool looks at this from the payback-timeline angle.
Financing the entire system cost means paying interest on every dollar of it, which adds up over a 15 to 25-year term. On a $28,000 system at 6.99% APR over 20 years, that's about $24,060 in total interest, on top of the original price. A zero-down loan isn't free, it just moves the entire cost into the monthly payment. The CFPB's explainer on how loan amortization works covers why interest accumulates this much over a long term.
A $5,000 down payment on that same loan lowers the monthly payment by about $39 and saves roughly $4,296 in total cost. That's a meaningful return on a relatively small upfront amount, assuming you have cash available that isn't earmarked for something else. The total cost of ownership calculator can help you see this alongside your full ownership costs.
Removing the upfront cost barrier is one of the main reasons solar loans became popular, since it lets homeowners go solar without a large cash outlay. Some existing loans were structured with the expectation that the borrower would apply a federal tax credit refund toward the balance around month 12 to 18, a mechanic the combined loan and rebate timing tool walks through in detail, though it now only applies to systems installed by December 31, 2025, with unused credit carrying forward.
If you're taking out a new loan in 2026, confirm it isn't structured around an assumed tax credit paydown that no longer applies to your situation, since a step-up payment tied to a credit that never arrives could catch you off guard partway through the term. If your loan does include such a structure and you skip the expected payment, it typically re-amortizes at a higher ongoing payment to account for the larger remaining balance. Confirm with your lender exactly how your specific loan is structured before assuming your monthly payment will stay at the initial quoted rate. The federal solar tax credit calculator can help confirm whether a carried-forward credit genuinely applies to your situation.
Some lenders price zero-down loans at a slightly higher APR than loans with a down payment, since the lender is taking on more risk by financing the full amount. Always compare the APR quoted at $0 down against the APR quoted with a down payment, not just the payment amount, using the loan APR impact calculator. The down payment impact calculator can also show how a range of down payment amounts, not just one, changes your total cost. The CFPB's issue spotlight on solar financing covers general financing considerations worth reviewing too.
Questions
A zero-down loan is a reasonable choice if it keeps your cash available for other needs, but it does mean financing the full system cost and paying interest on all of it. On a $28,000 system at 6.99% APR over 20 years, adding a $5,000 down payment instead saves about $4,296 in total cost.
Yes, proportionally. A $5,000 down payment on a $28,000, 20-year loan at 6.99% APR lowers the monthly payment from about $217 to $178, a difference of roughly $39 a month, while also reducing total interest paid over the loan.
Zero-down financing removes the biggest barrier to going solar, a large upfront cost, which is why most solar lenders offer it as a standard option. It shifts the entire cost into the monthly payment, ideally kept close to or below the expected bill savings.
Only if your system was installed by December 31, 2025, with unused credit carrying forward, since the federal residential credit expired for new installs after that date. Some older loan structures still include a built-in step-up payment expecting a credit paydown around month 12 to 18. If you're taking out a new loan today, confirm it isn't built around that same assumption, since it no longer applies.
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