Solar design and proposal software turns a roof and a utility bill into a permit-ready array layout, an annual production estimate, and a signable customer proposal. Expect to pay anywhere from $0 to roughly $300 per user per month in 2026, depending on whether you use a free platform funded by hardware and lender partners or a seat-based design suite. For most residential installers, the deciding factor is not the design engine. It is whether the proposal can price a lease or PPA correctly now that the 30 percent homeowner tax credit is gone.
Key takeaways
- OpenSolar remains free at its core because hardware distributors and lenders pay for placement in the platform, though advanced shading, white-label proposals, e-signature, and the CRM module are paid add-ons.
- Aurora Solar does not publish list pricing openly. Independent 2026 pricing breakdowns put its tiers near $159, $219, and $259 per user per month on annual billing, with monthly billing running roughly 20 percent higher and some designs metered as credits.
- HelioScope, built for commercial and industrial arrays, is generally listed between about $99 and $300 per user per month depending on tier and export requirements.
- Production numbers carry legal weight. NREL's PVWatts is commonly cited at roughly plus or minus 10 percent annual accuracy, and a 2018 NREL study of 199 unshaded residential systems found median annual error near 5 percent.
- Section 25D expired on December 31, 2025 under the One Big Beautiful Bill Act. Any 2026 proposal that still shows a 30 percent homeowner credit on a cash or loan deal is quoting a number that no longer exists.
Why solar quoting is not like other trades' estimating
Solar estimating carries a burden no other residential trade has: the quote is also a financial forecast. A roofing estimate has to be right about squares and waste. A solar proposal has to be right about azimuth, tilt, shading, inverter behavior, utility rate structure, escalation assumptions, and a 25 year payback the homeowner will hold you to. Get the layout right and the production model wrong, and you have sold a system that underperforms its own paperwork.
That is why solar tooling merged design, takeoff, and proposal into one product while other trades kept them separate. The measurement step (roof planes, obstructions, setbacks, keepout zones) feeds the simulation, which feeds the savings math, which feeds the contract. Break that chain across three tools and you add a transcription error at every handoff. Contractors arriving from general construction should skim our roundup of digital takeoff software mainly to see how little of the plan-based world transfers to a rooftop array.
What solar design and proposal platforms cost in 2026
Solar platform pricing splits into three models: free with monetized partnerships, per-seat subscriptions, and metered credits per design. Several vendors now mix seats and credits, which makes sticker price a poor comparison tool. Figures below reflect published vendor pricing and independent 2026 pricing breakdowns as of mid-2026, so treat them as ranges rather than quotes.
| Platform | Pricing model | Typical 2026 cost | Best fit |
|---|---|---|---|
| OpenSolar | Free core, paid add-ons, funded by hardware and finance partners | $0 base; add-ons for advanced shading, branded proposals, e-signature, financing integrations, and CRM | Residential installers under roughly 50 systems per year, and anyone testing solar as a new revenue line |
| Aurora Solar | Per user, plus credits for certain designs and AI modeling | Roughly $159 to $259 and up per user per month on annual billing; monthly billing about 20 percent higher | Residential teams that want high-fidelity shade analysis and sales proposals in one system |
| HelioScope | Per user subscription by tier | Roughly $99 to $300 and up per user per month, higher tiers for bankable commercial export | Commercial and industrial design work where the yield report goes to a lender |
| Solargraf | Per user, proposal-first | Scalable per-seat pricing, quoted by sales | Sales-rep-heavy operations that want fast in-home proposals over deep engineering |
| PVWatts (NREL) | Free public tool | $0 | Sanity-checking another tool's production number, never as the proposal itself |
Two cost traps repeat. Credit-based metering means a busy month can cost far more than the per-seat sticker suggests, so model your design volume before signing an annual term. And free platforms recover revenue elsewhere: once shading, e-signature, and financing integrations are separate line items, the all-in cost can land near a paid competitor. Price the configuration you will actually run, not the tier name.
Production modeling: where the accuracy actually comes from
Production modeling converts a layout into predicted kilowatt-hours per year, and its accuracy depends far more on the shade and weather inputs than on the simulation engine. Typical meteorological year data represents a long-run average, so year-to-year weather swings alone move real output by several percentage points. NREL positions PVWatts around plus or minus 10 percent annual accuracy, and its 2018 study of 199 unshaded residential systems reported median annual error near 5 percent. Unshaded is the operative word.
Shade is where cheap models fail. Optical shading is only part of the loss, since electrical mismatch between modules in a string compounds it, and the combined effect can cut annual yield materially on a tree-heavy lot. Tools that build shade from high-resolution imagery or LiDAR report tighter tolerances than satellite-only estimates, which is the practical reason installers pay for higher tiers. Ask each vendor which data source builds the obstruction model, at what resolution, and how the tool handles optimizers and microinverters, which change the shading penalty substantially.
The 2026 change that breaks old proposal templates
The Section 25D residential clean energy credit ended on December 31, 2025 under the One Big Beautiful Bill Act, with no phase-down. Systems placed in service on or after January 1, 2026 earn the homeowner nothing under 25D on a cash or loan purchase. Third-party ownership survives: under a lease or power purchase agreement, the system owner claims the credit under Section 48E and passes the benefit through as a lower payment, which is why prepaid leases have spread quickly.
This is a software problem, not only a sales problem. Your proposal tool has to model TPO structures natively: escalators, buyout schedules, prepaid options, and a utility comparison that does not silently assume a 30 percent credit line. Ask any vendor to show a live 2026 lease proposal and a loan proposal side by side before you buy. If financing is a growing share of how you close, our breakdown of Sunlight, Mosaic, and EnerBank against Hearth covers how the lender side differs, and our kitchen table guide to pitching financing covers presenting monthly payments without losing the room.
Must-have features for a solar estimating stack
Solar design and proposal software earns its subscription when one address flows from imagery to signed contract without retyping. Before you demo anything, check for these:
- Roof modeling from real imagery with obstruction detection, per-plane azimuth and tilt, and fire code keepout enforcement.
- Shade analysis you can defend, with a stated data source and resolution, plus module-level electronics modeled correctly.
- A utility rate library with true-up logic, including net billing and time-of-use schedules, since the savings number depends on the tariff more than the array.
- TPO, lease, PPA, and loan modeling in one proposal, with 2026-correct incentive handling.
- Battery sizing tied to backup loads, not to a flat percentage of array size.
- Permit-ready plan set output, or a clean handoff to a plan set service, because the design you sold has to survive the AHJ.
- E-signature and change orders inside the proposal. Our roundup of proposal software for contractors covers what a signable proposal needs across trades.
- CRM and pipeline connection so designs attach to a lead record. Solar sits close to electrical work, and our ranking of CRMs for electrical contractors is a reasonable starting shortlist if your platform's built-in CRM is thin.
How to evaluate solar design and proposal software
- Count your design volume first. Pull the last 90 days of proposals. That number decides whether free-plus-add-ons, per-seat, or credits is cheapest for you.
- Run your worst roof through every trial. Use a real shaded, multi-plane, tree-lined job, not the vendor's demo ranch house, and compare predicted production across tools.
- Check the model against a system you already installed. Feed in a job with 12 months of monitoring data and see how close the software lands. This is the single most useful test you can run.
- Demand a 2026 TPO proposal. Verify the tool no longer applies a homeowner credit to cash and loan deals, and that lease and PPA math is current.
- Confirm the utility rates for your actual territory are in the library and up to date, including any recent net metering change in your state.
- Time the full path. Measure minutes from address entry to a proposal sitting in the homeowner's inbox. Under 20 minutes for a standard residential roof is a fair 2026 bar.
- Price the second year. Add per-seat fees at your headcount, credit consumption at your volume, and every paid add-on before comparing plans.
Common mistakes solar contractors make when buying
- Choosing on design fidelity alone. Engineering-grade simulation is worth paying for on commercial jobs. On a 7 kW residential roof, proposal speed and financing accuracy close more deals.
- Treating free as free. Add-on pricing for shading, branding, e-signature, and financing can quietly rebuild a full subscription cost.
- Shipping last year's savings math. A proposal showing a 30 percent federal credit on a 2026 cash purchase is a consumer complaint waiting to happen.
- Presenting production as a promise. Quote it as a modeled range with a stated basis, and put the assumption in writing.
- Letting the design tool serve as a CRM it is not. Solar sales cycles are long, and follow-up dies in software built for arrays instead of pipelines.
- Skipping the permit reality check. A layout that ignores fire setbacks or structural limits gets redesigned after the sale, on your margin.
Frequently asked questions
How much does solar design and proposal software cost in 2026?
Plan on $0 to roughly $300 per user per month, with OpenSolar free at its core and paid platforms such as Aurora and HelioScope generally landing between about $99 and $300 per seat per month on annual billing, per vendor pricing and independent 2026 pricing breakdowns. Add-ons and credit-metered designs can push real spend well past the headline tier, so budget the configuration you will run.
Is OpenSolar really free?
The core design and proposal functionality is genuinely free, because OpenSolar is funded by hardware distributors and financing partners rather than user subscriptions. Advanced shading, white-label proposals, e-signature, financing integrations, and the CRM module are sold separately, so a fully equipped OpenSolar account is not a zero-cost account.
How accurate are solar production estimates?
For clean, unshaded residential systems, mainstream models are usually within about 5 to 10 percent of actual annual output, with NREL citing roughly plus or minus 10 percent for PVWatts and median error near 5 percent in a 199-system study. Accuracy drops fast with shading, and typical meteorological year weather data means any single year can differ from the model even when the design is right.
Do I still show homeowners the 30 percent tax credit?
Not on a cash or loan purchase placed in service in 2026 or later, because Section 25D expired at the end of 2025. The credit is still reachable through third-party ownership, where the system owner claims it under Section 48E and passes the value through in the lease or PPA payment, so your proposal software needs to model those structures correctly.
Do I need separate design and proposal tools?
Most residential installers no longer do, since the major platforms now bundle design, production modeling, and proposal generation in one license. Separate tools still make sense when a commercial pipeline needs bankable yield reports from an engineering-grade simulator while your sales team runs a lighter proposal product for residential jobs.
Can AI speed up solar quoting the way it has other trades?
Yes for the sales layer, cautiously for the engineering layer. Automated roof detection and auto-design cut minutes off every job, and our look at AI-powered quoting and estimating shows the same pattern across trades, but a human still needs to review shade, setbacks, and structural assumptions before the number goes to a homeowner.
Next step: pick two platforms, run the same shaded address through both trials, and compare their production numbers against a system you installed last year with real monitoring data. Then price the full second-year cost at your design volume. For estimating tools across other trades, start with our roundup of the best estimating software for contractors.