💡 “How can you design a solar energy system without spending thousands on professional software?”
Whether you are a student, an entrepreneur, or an engineer, finding free solar design software can save time, reduce costs, and make solar technology accessible to everyone. In this article, we’ll explore 12 of the best free and easy-to-use solar panel design tools that will help you plan and optimize your projects.
🌞 Part 1: For Beginners (Non-Experts)
1. PVWatts – Simple Energy Estimates
Developed by NREL, PVWatts helps estimate the electricity production of a grid-connected solar panel system anywhere in the world.
- ✅ Easy interface
- ✅ Quick results
- ✅ Perfect for small projects
👉 Try it here: https://pvwatts.nrel.gov/
2. Global Solar Atlas – Free Solar Resource Data
Funded by the World Bank, this tool provides free global solar resource data and is ideal for site selection.
- ✅ Free maps
- ✅ Resource assessment
- ✅ Beginner-friendly
👉 Try it here: https://globalsolaratlas.info
3. Easy PV Basic
With Easy-PV, you can quickly and simply create a PV project online for free. The performance calculator and an instant schematic can be used to estimate the output of a PV system. The people at Midsummer Solar Wholesale designed and constructed Easy-PV.
This tool lets you input your load consumption and instantly receive system sizing recommendations.
- ✅ Simple inputs
- ✅ Great for students and homeowners
👉 Try it here: https://easy-pv.co.uk/
4. PV*SOL Online – User-Friendly Web Design
A simplified version of PV*SOL software, allowing you to create small PV system designs online.
- ✅ Free trial access
- ✅ Visual simulations
👉 Try it here: https://pvsol-online.valentin-software.com/
⚡ Part 2: For Professionals (Experts)
5. SAM (System Advisor Model)
A powerful solar design software developed by NREL, SAM offers detailed performance and financial analysis.
- ✅ Advanced simulations
- ✅ Bankable reports
- ✅ Widely used in research & development
👉 Try it here: https://sam.nrel.go
6. REopt Lite – Hybrid System Optimization
Also from NREL, REopt Lite helps design solar + storage systems with cost and savings analysis.
- ✅ Focus on battery integration
- ✅ Economic optimization
👉 Try it here : https://reopt.nrel.gov/tool
7. SISIFO – Academic Precision
Created by the Universidad Politécnica de Madrid, SISIFO simulates PV systems with high technical accuracy.
- ✅ On-grid and irrigation PV systems
- ✅ Great for academic use
👉 Try it here : https://www.sisifo.info/en/DataInput
8. PVGIS – European Research Tool
Offered by the European Commission’s Joint Research Centre, PVGIS is excellent for solar panel layout tool analysis.
- ✅ Global coverage
- ✅ Shading and performance modeling
👉 Try it here: https://pvgis.com/
9. HelioScope (Free Trial)
While the paid version is popular among engineers, the free trial of HelioScope is a great way to test professional-grade solar panel design tools.
- ✅ Cloud-based
- ✅ CAD-like precision
👉 Try it here: https://helioscope.aurorasolar.com/
10. OpenSolar
- ✅ Fully rendered, automated 3D designs
- ✅ After entering the site address, paint the to-scale panels right away
- ✅ Pitch, azimuth, and shading are automatically calculated, allowing you to customize system and proposal details in the Design Zone.
👉 Try it here: https://www.opensolar.com/
11. Diafem
12. ONXY SOLAR PV ESTIMATION
A brand-new app that allows you to determine how much energy a photovoltaic installation produces. Additionally, it gives you helpful data like the number of hours of light produced, the CO2 emissions avoided, and even the distance an electric car could travel using the energy produced by the PV installation!
🔗 Read More
📊 Updated Comparison Table (12 Tools)
| Tool | Best For | Level | Free Access |
|---|---|---|---|
| PVWatts | Quick energy estimates | Beginner | ✅ Free |
| SAM (System Advisor Model) | Technical & financial analysis | Expert | ✅ Free |
| REopt Lite | Hybrid PV + storage systems | Expert | ✅ Free |
| SISIFO | Academic simulations | Expert | ✅ Free |
| Global Solar Atlas | Site solar resource data | Beginner | ✅ Free |
| PVGIS | Worldwide PV performance | Expert/All | ✅ Free |
| PV*SOL Online | Visual PV layouts | Beginner | ⚠️ Limited |
| Easy PV Basic | Simple PV layout & system sizing | Beginner | ✅ Free basic version |
| HelioScope (Trial) | Professional CAD-like designs | Expert | ⚠️ Limited |
| Open Solar | Full project design & proposal platform | All levels | ✅ Free |
| Diafem | Off-grid & hybrid system sizing | Expert | ✅ Free academic tool |
| Onyx Solar PV Estimation | Building-integrated PV (BIPV) | Architect/Expert | ✅ Free tool |
Conclusion
Choosing the right free solar design software depends on your level of expertise and project needs. Beginners may prefer PVWatts or Global Solar Atlas, while professionals can benefit from SAM, REopt Lite, or PVGIS.
