About
Why this exists
The 30% federal residential solar credit (IRC §25D) expired for systems placed in service after 31 December 2025. Most solar calculators online still apply it. That is not a rounding error — on a typical purchase it is several thousand dollars of savings that no longer exist, and it is enough to turn a losing investment into an apparently winning one.
This site models the rules as they actually are in 2026, and shows its work. It also models the things sales quotes leave out: the dealer fee buried in a low-APR solar loan, the maintenance and the inverter you will replace around year 13, the fact that electricity exported to the grid is often worth a fraction of retail, and the fact that a dollar saved in 2046 is not worth a dollar today.
The part that makes it different
It can tell you not to buy. On our reference case, no way of getting solar in Texas returns its cost, and the page says so. In a state with full retail net metering, a home battery saves you close to nothing, and the battery page says that too.
The large comparison sites cannot say either of those things, because they earn when you request a quote. We do not collect your contact details, we do not generate sales leads, and there is no phone number field anywhere on this site. That is a constraint in the code, not a promise in the marketing — see the disclosure page for how the site is funded and what that could bias.
Who runs it
Home Energy Math is an independent, self-funded site run by a single developer. It is not owned by, funded by or affiliated with any solar installer, manufacturer, financier or marketplace. Worth stating because the biggest name in the category is not independent: EnergySage has been owned by Schneider Electric, a manufacturer of home energy hardware, since 2022.
Corrections
If a number here is wrong we want to know, and we would rather hear it from you than leave it up. Utility tariffs and state programmes change often and our data is only as current as its last review — every page carries the date it was last checked, and every state record carries its own provenance on the data sources page.
Email: [email protected]
Related
Methodology and assumptions · Data sources and provenance · Advertising disclosure · Privacy policy · Terms of use