Reading your combined loan and rebate timing result
Who the tax credit half of this tool applies to now
The federal residential solar tax credit expired for systems installed after December 31, 2025. If that's your situation, only the local rebate portion of this comparison applies to you, which still works exactly as described below. If your system was installed by that deadline and you have an unused credit carrying forward, the timing comparison here remains accurate for combining that credit with a rebate. The IRS Form 5695 instructions confirm the current eligibility rules.
Why timing changes how much each incentive is worth
A dollar applied to a loan balance earlier avoids more future interest than the same dollar applied later, since interest compounds on whatever balance remains each month. An upfront local rebate, applied at signing, gets the full benefit of this timing regardless of the tax credit's status. A carried-forward credit, arriving whenever you claim it on a return, still helps significantly but starts from a smaller remaining opportunity to save interest the later it's applied. The early payoff savings calculator and the total interest paid calculator both show this same principle applied more broadly, not just to these two specific incentives. To compare paying cash, borrowing, leasing, or signing a PPA, the Department of Energy's guide to solar financing, leases, loans, and PPAs lays out each option.
What the numbers show in a typical scenario
On a $28,000 loan at 6.99% APR over 20 years with a $1,000 upfront rebate and a carried-forward credit applied as a paydown at month 14, the combined approach costs about $35,071 in total. That's roughly $1,859 less than applying only the credit without the rebate, purely from the rebate's earlier timing on top of its face value.
Why rebate timing varies by program
Not all local rebates work the same way. Some installers apply them instantly at the point of sale, directly reducing what you finance, while others require the rebate to be claimed separately after installation and paid out as a check or utility bill credit weeks or months later. Confirm the specific timing for your program, since it changes how much benefit you get from this comparison, and this part of the tool is unaffected by the change to the federal credit. The rebate deadline tracker can help you stay on top of when a specific program's window closes.
What if a carried-forward credit and a rebate arrive close together
If both incentives land around the same time, whether that's a delayed rebate or an early tax filing, you can combine them into one larger paydown at that point. It still meaningfully reduces the loan, just without the extra benefit of the rebate's separate, earlier timing this tool assumes by default.
How this fits into your broader loan strategy
If you have additional cash beyond a rebate or credit that you're considering putting toward the loan, the prepayment penalty cost calculator is worth checking first, since a larger extra payment could trigger a fee on some loans that a smaller one wouldn't. A battery changes the loan amount. The backup runtime estimator in our Battery & Storage section can help you size it before you borrow, so you do not pay interest on spare capacity.