Financing
Enter your loan, savings, and an assumed utility rate increase. Find the exact point cumulative savings catch up to and pass what you've paid, month by month.
How it works
Step 1
Use your actual loan terms and a realistic year-1 monthly savings figure. The monthly payment vs bill savings comparison can help you build that savings estimate from your usage.
Step 2
3% a year reflects the long-run US average, but your local utility's history may run higher or lower. Try a couple of assumptions to see the range, or use the down payment impact calculator if you want to see how a down payment changes this same timeline.
Step 3
Some scenarios turn cash-flow positive in year one, others don't until after the loan ends. Either result is useful information for planning.
This tool tracks a running total each month: bill savings minus the loan payment, accumulated from month one. The month that cumulative total crosses zero and stays positive is your breakeven point, the moment solar has fully paid for its own monthly cost so far, separate from any tax credit that might apply to your specific situation. The monthly payment vs bill savings comparison shows the single-month snapshot version of this same math. Before you sign a loan, the Consumer Financial Protection Bureau's report on solar financing is worth reading for its findings on dealer fees and loan terms.
Your loan payment is fixed for the entire term, but the value of the electricity your system replaces grows every year utility rates rise. That means even a system that starts out running a monthly deficit against the loan payment can close that gap steadily and eventually turn positive, sometimes years before the loan itself ends. The first-year solar savings estimate can help you set a realistic starting-point figure for that math.
This is common for shorter loan terms or systems sized to generously offset future usage growth, and it doesn't mean the investment is bad. The full picture includes the years after the loan is paid off, when the entire monthly savings becomes pure gain with no offsetting payment at all. Borrow less by claiming first. The rebate stacking tool in our Rebates & Incentives section estimates the federal credit and rebates so you can size the loan to the net cost.
A shorter loan term means a higher monthly payment, which can push your breakeven point later or eliminate it entirely within the loan window, even though the shorter term saves more in total interest. Compare a few different terms using the loan term comparison tool to see how that tradeoff plays out for your specific numbers.
Panel output typically declines by about 0.5% a year, a small effect not modeled here that slightly reduces savings growth over time, partially offsetting the benefit of rising utility rates. It also doesn't include maintenance costs, which are minimal for most systems but not zero over 20-plus years. The total interest paid calculator can help you see the loan side of the picture in more detail. For a broader look at how financing decisions interact with these numbers, see the DOE's homeowner's guide to solar financing and the CFPB's issue spotlight on solar financing.
Questions
It depends heavily on the loan payment relative to bill savings and how fast utility rates rise. A system with a loan payment close to or below year-1 savings can turn cash-flow positive almost immediately, while a system with a higher payment relative to savings may not break even until several years in, or not until after the loan is paid off.
Because your loan payment stays fixed while the value of the electricity your system replaces increases each year utility rates rise, the gap between payment and savings narrows over time even without any change to the loan itself. This is why a system that starts slightly cash-flow negative can still turn positive well before the loan ends.
That's a real possibility for shorter loan terms or systems sized well beyond current usage, and it doesn't mean the system is a bad investment, only that the payback shifts to after the loan ends. Once the loan is paid off, the full monthly savings become pure gain for the remainder of the system's productive life.
No, this tool assumes stable output and focuses on the utility rate side of the equation. Panels typically decline in output by about 0.5% a year, a small effect that partially offsets rising utility rates but usually doesn't change the overall cash-flow timeline dramatically.
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