Your roof is an asset. Find out what it earns.
Free residential solar design and analysis calculator. Get accurate design and performance estimates for your address.
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Built on Google Solar imagery and PVWatts® modeling, the same data installers use. Works for most US urban and suburban addresses. Nothing is saved without your consent.
Most free tools scale a national average by your bill. This one models your building in 3-D, places panels on real roof planes, and simulates production hour by hour. Then it compares cash, loan, lease and PPA over 25 years.
It also shows what the leasing company makes on your roof. We have not found another free tool that does.
Send us your email and home address and, within one business day, we'll send you a report on your own home, about 25 pages: your best system with and without a battery, the payback and savings whether you pay cash, finance, lease or sign a PPA, what changes the answer (your bill, the system's size, an EV, the price you pay), every incentive that applies to you, and a detailed shading analysis of your roof. Free, and with no obligation.
If the numbers are good, we'll say so plainly. If you then want to go ahead, we'll introduce you to the one local installer worth talking to, chosen through an eight-step vetting process (learn more): licensed, insured and certified, with its own crews, no disciplinary history or predatory financing, and still around in ten years to honor the warranty.
Go solar through that introduction and we pay you up to $500 from the fee the installer pays us.
No phone number, and nobody will call you.
Paste a quote. It pulls out the price, size, financing and the escalator buried on page eleven, then checks them against an independent model of the same roof. Built by a former renewable energy research scientist.
We are not selling you the system, so we have no reason to flatter the quote.
We ran detailed studies on over 100 randomly chosen homes with the same calculator you have access to here. In our blog, we publish every detail, including the ones that don't flatter solar. Nothing is cherry-picked; every roof is measured individually.
Every figure in those studies came out of this calculator, and you can reproduce any of them on your own address in about a minute. That is the point of reading them: they show you what this tool is actually doing with your roof.
The best design for your address
Every panel is placed where it earns the most on your roof, and the system is sized to your bill. Change the bill or the panel count and this updates.
A drawing, not your roof. With a free account this runs on your own home, with your own panels and your own numbers.
A highly detailed and accurate shade aware design. Design Studio ranks every spot on your roof by the sun it actually gets, places the panels on the best ones, and skips what your trees shade. You do not have to understand any of it for it to be right.
Manually make edits to your system with a free account. Resize the system, drop a panel on a different spot, correct a roof face — or reset to the best layout in one tap.
Detailed list of codes that apply to your system and address. The building and electrical codes for your address are already accounted for in this design. With a free account you can see the exact editions and the full list of code rules your installer must meet.
Prefer an expert to do it?
A drawing, not your roof. With a free account this plays on your own home, from Google’s 3-D model of it.
Your results already include your roof's shading. Every panel's output is measured from Google's 3-D model of your home and the trees around it, so the design, production and savings you see here account for it.
With a free account, you can watch it. Shade Studio plays the shade across your own roof, hour by hour and month by month, and lights up each panel as the sun reaches it.
Prefer an expert to do it?
Design it yourself
See every panel on your roof, choose which ones to use, and correct each roof face. Free with an account.
Prefer an expert to do it?
Your solar snapshot
Compare Plans
Crunching the numbers…
Open for SIA’s notes on this design
Informational estimate, not an installation quote. “25-yr savings” is cumulative and net of what you pay (purchase, loan, lease, or PPA). Battery storage is not included in this snapshot. See the full methodology.
Get your full analysis — free
Two ways to go from here — both free, no strings.
Have SIA build it for you
SIA’s founder — an ex‑solar‑energy scientist, and the person who built this calculator — hand‑builds you a ~25‑page report: every incentive that actually applies to you, your utility’s real export rate, the code and interconnection work, EV and battery, and the financing traps to avoid. Vendor‑neutral, within one business day.
See a real exampleOr explore it yourself
Create a free account and open the full calculator: design your roof by hand, compare batteries, run the financials, and export a proposal.
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Planning to move?
Few people stay put for 25 years, and leaving early is where these deals differ most. If you sold in year we will show where you would stand.