About SolarSavingsMath
Why this site exists
Search "solar payback calculator" and most of what you find is a lead form wearing a calculator costume. You enter your address and phone number, you get a vague range, and within an hour four installers are calling you. The math was never the point — your contact information was.
That model works fine for the companies running it. It works badly for you, because a $20,000–$40,000 decision deserves arithmetic you can actually inspect before anyone starts selling to you.
So this site does the opposite. Enter your numbers, see the result immediately, no email required. If you later decide you want installer quotes, we will point you toward options and tell you plainly when we earn something from that referral.
Who writes this
SolarSavingsMath is written and maintained under the byline Riley Kim, the editorial name for this publication. We are a small independent operation, not a solar installer, not a lead broker, and not owned by any energy company.
We think trust on a site like this should come from work you can verify rather than credentials you cannot. So instead of asking you to believe a biography, we publish the formulas, cite the primary sources, and show the assumptions behind every default value. If a number is wrong, the math is right there to check — and we will fix it.
How the calculators are built
Every calculator runs entirely in your browser. Your inputs are never transmitted to us or to anyone else. Close the tab and they are gone.
The underlying data comes from primary sources:
- Sun hours and production estimates — National Renewable Energy Laboratory (NREL)
- Electricity rates and rate inflation — U.S. Energy Information Administration (EIA)
- Federal tax credit rules — IRS guidance on the Residential Clean Energy Credit (Section 25D)
Full formulas, default values, and known limitations are on the methodology page.
How we make money
Running a site costs money, so we should be direct about where ours comes from. Two sources: display advertising, and referral commissions when a reader chooses to request installer quotes through a partner we link to.
Neither one changes a single number in any calculator. The formulas do not know or care whether you click anything, and a referral link never costs you more than going direct. Our affiliate disclosure spells this out in full.
What we will not do
- Sell, rent, or broker your personal information
- Require an email address to show you a result
- Adjust a calculator's output to favor a partner
- Present a sponsored placement as an editorial recommendation
Corrections
If a formula looks wrong, a rate is out of date, or a state's net metering rules have changed, tell us. Solar policy moves quickly and we would rather be corrected than confidently wrong. Reach us through the contact page.
Not financial advice
These calculators are educational estimating tools. They are not financial, tax, or engineering advice. Actual costs, incentives, and production vary by site, utility, and installer. Confirm tax credit eligibility with a qualified tax professional and get binding quotes before committing to a purchase.