Key Takeaways
- OpenSolar is a free platform with AI-powered design, proposals, and 25,000+ users worldwide
- PVsyst is the global standard for bankable PV simulation, trusted by banks and investors
- OpenSolar degrades above 500 kW and lacks detailed engineering documentation
- PVsyst has no design tools, no proposals, and no cloud access
- Neither tool produces SLDs, three-line diagrams, or permit packages
- SurgePV offers simulation, design, proposals, and engineering at $1,499/yr
Quick Verdict
Our Verdict
OpenSolar and PVsyst target different audiences with almost no overlap. OpenSolar is for residential installers who need a free design and proposal tool. PVsyst is for engineers who need bankable simulation reports. If you’re a growing team that needs accurate simulation and a professional project workflow without the limitations of either tool, SurgePV covers both at $1,499/yr.
Company Overview
OpenSolar
Founded
2016
Headquarters
Melbourne, Australia
Focus
Free solar design & proposals
Best For
Small residential installers
Pricing
Free (marketplace-funded)
PVsyst
Founded
1992
Headquarters
Satigny, Switzerland
Focus
Bankable PV simulation
Best For
Financial due diligence & utility-scale
Pricing
≈$800-1,400/yr
Feature Comparison
| Feature | OpenSolar | PVsyst |
|---|---|---|
| Cloud-Based | ✓ | ✗ (Desktop only) |
| Panel Layout Design | ✓ (AI-powered) | ✗ |
| Satellite Imagery | ✓ | ✗ |
| Bankable Simulation | ✗ (Basic estimates) | ✓ (Industry standard) |
| Detailed Loss Modeling | ✗ | ✓ (30+ parameters) |
| P50/P90 Reports | ✗ | ✓ |
| Proposal Generation | ✓ (Interactive) | ✗ |
| Financial Modeling | ✓ (ROI, payback, loans) | Basic economic evaluation |
| Single-Line Diagrams | ✗ | ✗ |
| Battery Storage | ✓ (Basic) | ✓ |
| Commercial Projects (>100 kW) | Degrades above 500 kW | ✓ |
| Utility-Scale | ✗ | ✓ |
| Meteo Data Sources | Limited | ✓ (15+ databases) |
| Free to Use | ✓ | ✗ ($800-1,400/yr) |
| API Access | ✓ | ✗ |
| Operating System | Any (web browser) | Windows only |
Design & Proposals
OpenSolar: Design and Proposals, With Limits
OpenSolar’s core workflow is built around fast residential design and interactive proposals. The AI auto-design places panels on rooftops using satellite imagery, generates an energy estimate, and feeds everything into a customer-facing proposal with financing options, bill savings projections, and environmental impact metrics.
For a small residential installer doing 5-20 projects per month, OpenSolar delivers solid value at zero cost. The proposals are professional enough for homeowner presentations, and the platform includes basic CRM and pipeline tracking.
Where OpenSolar falls short is in engineering depth. The platform does not generate SLDs, three-line diagrams, or permit packages. It also lacks detailed BOM generation with pricing. Teams that need engineering documentation still need AutoCAD or another tool to complete their deliverables.
PVsyst: No Design, No Proposals
PVsyst offers zero design or proposal capabilities. You input system specifications manually, run a simulation, and export a technical PDF. There are no panel layout tools, no satellite imagery integration, no proposal templates, and no customer-facing documents. PVsyst expects you to bring a fully specified system design from another tool.
Simulation & Accuracy
OpenSolar: Good Enough for Residential Sales
OpenSolar generates energy production estimates that are sufficient for residential proposals. The platform uses satellite-derived irradiance data and basic system parameters to calculate annual kWh production. These estimates are accurate enough to quote a homeowner but would not pass scrutiny from a lender or independent engineer.
OpenSolar’s AI design feature can generate a panel layout and energy estimate in minutes, which is exactly what residential sales teams need for speed-to-quote. The platform has over 25,000 users who rely on it for this purpose.
The problem surfaces on larger projects. Above 500 kW, OpenSolar’s performance degrades and its simulation simplifications become more significant. The platform was not built for commercial-scale accuracy.
PVsyst: The Bankable Standard
PVsyst has three decades of validated simulation results behind it. Banks and investors worldwide accept PVsyst reports as the basis for project financing decisions. The software models 30+ individual loss parameters, from module quality scatter and LID (Light-Induced Degradation) to inverter clipping and AC cable losses.
For utility-scale projects, PVsyst’s detailed bifacial modeling, tracker algorithms, and uncertainty analysis are unmatched. The software connects to 15+ meteorological databases and allows engineers to build multi-source weather datasets that form the basis of reliable P50/P75/P90 probability distributions.
The cost is complexity. PVsyst requires trained operators who understand what each parameter does. A junior engineer can easily misconfigure a simulation and produce a report that looks credible but is wrong.
Pricing Comparison
| Cost Factor | OpenSolar | PVsyst |
|---|---|---|
| Annual Cost | Free | ≈$800-1,400/yr |
| License Type | Free, cloud-based | Per-seat, desktop |
| Revenue Model | Marketplace commissions | Software license |
| Design Included? | Yes | No |
| Proposals Included? | Yes | No |
| Bankable Reports? | No | Yes |
| Engineering Docs? | No | No |
OpenSolar is free but limited. PVsyst is paid but simulation-only. Neither covers the full workflow.Looking for a Better Alternative? Try SurgePV
Get design, simulation, proposals, and engineering in one platform — no size limits, no missing features.
Start Free TrialNo credit card required · Scales to 5 MW · Full feature access
Pros & Cons Side-by-Side
OpenSolar
Pros
Cons
PVsyst
Pros
Cons
Who Should Choose What?
| Your Situation | Choose OpenSolar | Choose PVsyst |
|---|---|---|
| Zero-budget residential installer | ✓ | |
| Need fast design-to-proposal workflow | ✓ | |
| Small residential projects only | ✓ | |
| Need bankable reports for project financing | ✓ | |
| Utility-scale projects | ✓ | |
| Detailed loss and uncertainty analysis | ✓ | |
| Commercial projects above 500 kW | ✓ | |
| Need engineering docs and SLDs | Neither (consider SurgePV) | |
| Need simulation + design + proposals | Neither (consider SurgePV) | |
Best Alternative: SurgePV
OpenSolar gives you design without credible simulation. PVsyst gives you simulation without design. Neither produces engineering documents. A growing installation company inevitably outgrows both — OpenSolar because it can’t help you scale beyond residential, and PVsyst because it can’t help you sell.
SurgePV solves this by combining all project phases in one platform:
- Design: Cloud-based AI auto-layout on satellite imagery, working from 5 kW rooftops to 5 MW commercial arrays
- Simulation: 8760-hour energy yield analysis with P50/P75/P90 confidence levels and detailed loss modeling
- Proposals: Professional web and PDF proposals with global financial modeling, multi-currency support, and cash/loan/lease/PPA structures
- Engineering: Native SLD generation, three-line diagrams, automatic wire sizing, BOM, and permit package export
- No size limits: Handles residential through commercial without performance degradation
At $1,499/yr for 3 users, SurgePV costs more than OpenSolar’s free tier but delivers professional-grade tools that scale with your business. It costs slightly more than PVsyst but includes design, proposals, and engineering that PVsyst lacks entirely.
For teams that have outgrown OpenSolar’s limitations or are tired of PVsyst’s workflow gaps, start a free trial to see the full platform.
Frequently Asked Questions
Is OpenSolar really free?
OpenSolar offers a free tier that includes basic design and proposal features. The free model is supported by financing and equipment marketplace commissions. Some advanced features may require paid access.
Is PVsyst more accurate than OpenSolar?
Yes. PVsyst offers significantly more granular simulation with 30+ configurable loss parameters and bank-accepted P50/P90 reports. OpenSolar provides basic energy estimates sufficient for residential proposals but not for financial due diligence.
Can OpenSolar handle commercial projects?
OpenSolar works for small commercial projects but degrades above 500 kW. Its design tools and simulation are optimized for residential-scale systems. For large commercial or utility-scale, OpenSolar is not suitable.
Does PVsyst generate proposals?
No. PVsyst is a simulation engine only. It produces technical energy yield reports but has no proposal builder, no customer-facing documents, and no financial modeling for end customers.
Does OpenSolar generate SLDs?
No. OpenSolar does not produce single-line diagrams or detailed electrical engineering documentation. Teams needing SLDs require a separate tool like AutoCAD or a platform like SurgePV that includes native SLD generation.
What is PVsyst used for?
PVsyst is used for bankable photovoltaic energy yield simulation and financial due diligence. Engineers and investors rely on its detailed loss modeling, P50/P90 probability analysis, and multi-source weather data for project financing decisions.
Can I use OpenSolar for utility-scale projects?
No. OpenSolar is built for residential and small commercial projects. Above 500 kW, its performance degrades and it lacks the simulation depth, bifacial modeling, and tracker support needed for utility-scale work.
Does OpenSolar work on Mac?
Yes. OpenSolar is cloud-based and runs in any modern web browser on Mac, Windows, Linux, tablets, and mobile devices. PVsyst is desktop-only and Windows-only.
How much does PVsyst cost?
PVsyst costs approximately $800-1,400 per year for a single-seat desktop license. The price varies by region and license type. There is no free tier.
What’s a better alternative to both OpenSolar and PVsyst?
SurgePV combines detailed simulation with professional design, proposals, and engineering tools in one cloud-based platform at $1,499/yr. It scales from residential to 5 MW commercial without the limitations of either OpenSolar or PVsyst.
