What solar actually costs you, and when it pays you back
Real production data for your roof, your utility's filed electricity rate, and the true price now the 30% federal credit has ended. You get the number and the workings - not a form that sends your phone number to four installers.
- No email requiredNot asked for, not stored
- No phone numberNobody will ever call you
- No sales callsYour details are not sold on
- Every figure sourcedNREL data, shown and dated
Why this calculator gives a different answer
Type your ZIP into most solar sites and you get an encouragingly short payback, then a phone call. Three things drive that gap, and this calculator handles each of them differently.
The federal tax credit no longer exists
For a quarter of a century the 30% Residential Clean Energy Credit was the single biggest lever in solar economics. It was terminated for purchases after 31 December 2025. On a $26,000 system that is $7,800 that used to come back to you and now does not. A calculator still applying it will tell you eight years when the answer is eleven.
Surplus power is usually worth less than retail
Oversized systems look good on paper if you assume every exported kilowatt-hour earns the full retail rate. Net metering has been rolled back in California, and other states are following. This calculator values exports at zero and counts only the electricity you would have bought anyway. If your utility still pays retail, treat the result as a floor rather than a ceiling.
Roofs have a size limit
A bill-driven estimate can quietly conclude you need 25 kW of panels. That is not a solar recommendation, it is a sign the model has run past physical reality - a typical home fits around 10 kW. When the maths produces a system your roof cannot hold, this calculator says so instead of pricing an array that will never exist.
What it will not tell you
It has not seen your roof. It does not know about the oak tree that shades your south face until two in the afternoon, your local permit costs, whether your panel needs upgrading, or the state and utility rebates that may apply where you live. Those can move the answer by thousands in either direction. Use this to decide whether solar is worth pursuing at all, and to sanity-check the quotes you get.
Common questions
Why do you not ask for my email or phone number?
Because the calculator does not need them. Most solar estimate sites are lead-generation businesses: the number is the bait and your contact details are the product, sold to installers who then call you. This site makes no money from your details, so it does not collect them.
Is the 30% federal solar tax credit really gone?
Yes, for home purchases. The Residential Clean Energy Credit under IRC Section 25D was terminated by the One Big Beautiful Bill Act (P.L. 119-21), signed on 4 July 2025, for expenditures after 31 December 2025. Many calculators and sales scripts still apply it, which makes payback look about three years shorter than it is.
Where do the production numbers come from?
NREL's PVWatts v8 model, run against the weather station nearest your coordinates. It is the same model used across the US solar industry and it accounts for your latitude, local climate and typical system losses.
Where does my electricity rate come from?
NREL's Utility Rates v3 database, which maps your location to your serving utility's filed residential rate. If we have no verified rate for your area we say so and refuse to estimate, rather than substituting a national average that would produce a confident wrong answer.
Why does the estimate count surplus power as worth nothing?
Net metering rules are being cut back across the US and the buy-back rate varies enormously by utility. Rather than assume a generous rate, we only count electricity you would otherwise have bought. If your utility still pays full retail for exports, your real result will be better than the figure shown.
How accurate is the installed price?
It is the weakest figure on the page and it is labelled as such. Production is physics and your rate is a filed tariff, but price is a market number that varies by installer, equipment and roof complexity. We publish a range from published market surveys. If you have a real quote, enter its price per watt and the estimate uses that instead.
Does this replace getting quotes?
No. It tells you whether solar is worth pursuing at your address and what a fair quote looks like, so you can judge the ones you receive. A signed quote from an installer who has seen your roof beats any model.