About SIA

SIA answers one question honestly: does solar actually pay at your address? Not a generic estimate, not a sales pitch. A real model of your roof, the same data installers use, and a plain answer including when the answer is no.

It is free, it takes about a minute, and nothing is shared with anyone unless you ask.

Vision & mission

Vision. Homeowners made richer and more self-reliant by the roofs they already own.

Mission. To make home solar one of the best paying and reliable investments for homeowners.

The Solar Design Studio

The Design Studio is SIA's interactive solar tool. Enter a home address and it builds a real model of that roof — not a generic estimate — from high-resolution aerial imagery and shading-aware irradiance data, then simulates production with PVWatts® v8 from the National Laboratory of the Rockies (formerly NREL).

• Your actual roof. Panels are placed on real roof segments and ranked by shading-aware annual output. Click any panel to include or exclude it.
• Sized to your home. The default system targets roughly your estimated annual usage, using state-level residential load shapes — not the largest array the roof could physically hold.
• All four ways to pay, compared. Cash, loan, lease and PPA side by side over 25 years, including the fund-side economics that most third-party proposals leave out.
• Battery modelling. Hourly dispatch against your load profile and time-of-use rates, so storage value is calculated rather than assumed.
• An honest verdict. The Studio tells you when solar is a poor financial fit at your address, and why. We would rather say so than put you in front of a salesperson.

The Studio is free, and the full methodology — every model, data source and default assumption behind the numbers — is published at How this model works.

What you can do with it

• Model your roof. Enter an address and see what a system would produce, cost and save, with every assumption on screen and editable.
• Check a quote you were given. Paste it in and SIA reads the price, size, financing and escalator, then shows what those numbers mean against an independent model of the same roof.
• See the other side of a lease or PPA. The same contract modelled from the fund's perspective, so you know what the company makes before you negotiate.
• Find out what leaving early costs. Few people stay twenty-five years, so you can ask where you would stand if you sold in year eight.
• Get a human to look at it. Account holders can send a quote for a second opinion. One person reads it, and nothing goes to an installer.

How it makes money

Homeowners never pay. When the numbers genuinely work and you ask for it, SIA will introduce you to one vetted local installer, and that installer pays a flat fee. Never a list, never an auction, and never without you asking first. That is also why an honest “no” costs us nothing worth having: a lead that should not convert is worth nothing to an installer either.

Installer matching is not live yet. How it will work, how the vetting is done, and the economics behind it are written up at How installer matching works.

What SIA will not do

• Sell or share your details. There is no lead list.
• Ask for your phone number. Email is for signing in.
• Tell you solar is a good idea when the model says otherwise.
• Hide the assumptions. Every number is editable and the method is published.

Data sources

Roof geometry and irradiance come from the Google Solar API; production is simulated with PVWatts® v8; utility tariffs come from the OpenEI Utility Rate Database; and incentive programs come from the DSIRE® Database, managed by the N.C. Clean Energy Technology Center.

DSIRE data is licensed under Creative Commons Attribution-ShareAlike 4.0. We are grateful for their work making clean energy policy accessible.

Every source, refresh cadence and default assumption is listed in How this model works.