Reading the fine print on both programs
Why caps exist
Most rebate programs are funded from a fixed budget, whether that's a ratepayer surcharge on a utility bill or a state appropriation. A cap protects the program from paying out more on a single large system than the budget was designed to cover. Percentage-of-cost caps are common because they scale with system size automatically, unlike a flat dollar ceiling that hits every system the same way. For the exact rules on what counts, the IRS instructions for Form 5695 are the source to read.
What "stackable" actually means
Some programs are explicitly designed to work alongside others, since state agencies and utilities often coordinate on solar policy. Others exclude any system that received a different rebate, usually to prevent one project from drawing down two separate budgets. When in doubt, call the program administrator directly, or check the DSIRE database, rather than assuming based on what a neighbor received, since rules can change year to year. If you're weighing more than two incentive types at once, the rebate stacking tool handles a fuller mix including tax credits and SREC income.
Budget exhaustion is a real risk
Utility rebate programs funded from a fixed annual budget sometimes stop accepting applications mid-year once funds run out, then reopen the following January. If a program is close to its funding cap, applying earlier in the year improves your odds. The rebate deadline tracker helps you track application windows across multiple programs at once. The SREC explains the terms behind this estimate in plain language.
Comparing this to your federal number
Utility and state rebates typically run independently of federal law, which is worth remembering given how much the federal residential credit changed in 2026. Even with a $0 federal credit, a combined utility and state rebate can still meaningfully lower your upfront cost. Check the federal ITC calculator separately to see your full picture across all three levels.
With your rebate total in hand, the combined loan and rebate timing tool shows the monthly payment on the amount you still need to borrow.