Free versus paid solar design software is a procurement decision about the whole workflow. A licence price does not tell you whether a tool can produce the layout, simulation, electrical documentation or proposal your team needs. Compare documented capabilities and representative project outputs before paying to solve a problem that a free tool may already cover.
This comparison is based on official public documentation checked on 11 October 2026. It is not a benchmark of speed, yield accuracy or conversion rates. SurgePV publishes this page and sells solar software; the examples explain how to evaluate a purchase rather than claim that our subscription is cheaper for every team.
Price Model and Workflow Scope Are Separate Decisions
An energy calculator, engineering model and installer design platform are different products even when each has no licence fee. Mixing them into a single “free tools” column creates misleading comparisons. The same problem occurs when every paid tool is assumed to include permit services or customer proposals.
Use the following map to distinguish a tool’s documented role from the work that surrounds it.
| Product or workflow | Published access model | Documented role | Procurement question |
|---|---|---|---|
| OpenSolar | Platform advertised as free of charge | Design, sales and project-management workflows | Which services and templates apply to our market? |
| PVWatts | Free estimator | Preliminary production estimate | Are our site and loss assumptions defensible? |
| SAM | Free analysis software | Performance and financial modeling | Who will maintain and review the detailed model? |
| SolarEdge Designer | Vendor advertises free design software | SolarEdge-oriented design and proposal workflow | Does our equipment selection fit the supported workflow? |
| Paid design platform or service | Current contract or quotation | Scope varies by product and plan | Which required outputs are included in this specific offer? |
Sources are linked in the product column. This is a documented scope map, not an ordered ranking or tested feature score. Add your actual shortlist and written quotations before using it as a purchasing matrix.
Correcting a Common Electrical-Documentation Assumption
It is inaccurate to say that free software cannot generate single-line diagrams. OpenSolar’s official SLD page describes an integrated, editable generator and regional templates for Australia, the United States, the United Kingdom, Germany, Italy and Spain. A separate AutoCAD licence is therefore not a universal prerequisite for an OpenSolar SLD.
OpenSolar also documents permitting integrations. Integrated access to a service is not the same as that service being included at no charge. Confirm the plan-set, engineering-review and application scope with the provider before estimating the project’s document cost.
Check the actual submission
An automatically generated diagram still needs the project’s equipment, electrical ratings and jurisdiction-specific checks. A vendor’s compliance language does not replace review by the responsible qualified professional or acceptance by the authority reviewing the project.
This distinction changes the free-versus-paid decision. Buy the capability or service that is missing from your current workflow, not an assumed restriction attached to a price label.
Compare the Complete Cost Without Inventing a Benchmark
Include licences, optional imagery, third-party document services, onboarding, integration, data migration and staff time. List each item once. If an existing CAD licence is already used across the business, do not assign its entire annual cost to one solar project merely to make another product appear cheaper.
For labor, separate measured active time from waiting for a response or approval. Use the same project, inputs and required outputs for each workflow. Record rework as well as the first draft. A workflow that produces a quick but incomplete drawing has not finished the same job.
An Illustrative Labor Comparison
The following example is hypothetical. It is not a SurgePV test, vendor quote or claimed customer saving. Assume a team processes 12 comparable projects per month, reduces active preparation time by 0.5 hours per project, and values that time at $60 per hour.
| Input or result | Value | Basis |
|---|---|---|
| Comparable projects | 12 projects/month | Illustrative assumption |
| Active time difference | 0.5 hours/project | Illustrative assumption; replace with measured time |
| Internal labor value | $60/hour | Illustrative assumption, not an industry wage |
| Time difference | 6 hours/month | Projects × time difference |
| Labor-value difference | $360/month | Hours × labor value |
| Annual labor-value difference | $4,320/year | Monthly value × 12 months |
The governing formula is projects per month × hours per project × currency per hour. Units resolve to currency per month. The result excludes subscription changes, training, migration and financing, and it does not establish a cash saving. Staff capacity freed for other work may be valuable even when payroll is unchanged.
A subscription is justified only after comparing that conditional benefit with your actual incremental costs and the quality of the completed outputs. Do not add a higher close rate or fewer rejected permits unless you have evidence for those outcomes.
Run a Representative Project Before You Decide
Choose a project that resembles your normal workload. A clean demonstration roof cannot establish suitability for obstruction-heavy commercial sites or a mixed-equipment portfolio.
- Fix the equipment, survey inputs, tariff assumptions and required outputs.
- Run the existing workflow and record active work, handoffs and corrections.
- Run the candidate workflow with the same information.
- Review the layout, loss assumptions, diagrams, proposal and export files.
- Ask the responsible engineer or permitting specialist to identify missing checks.
- Reconcile the written commercial terms with the features demonstrated.
For team use, also test account permissions, revision history and how a second designer continues the project. These are evaluation questions; this page does not assert that every named tool provides every function.
Project Size Alone Does Not Establish a Software Limit
We do not apply a universal capacity cutoff to free software. SAM’s official documentation describes residential through utility-scale performance analysis. That does not turn it into an installer proposal platform, but it disproves the assumption that free analysis necessarily becomes unusable when a project grows.
Ask each vendor to demonstrate your intended capacity, array geometry, equipment and export requirements. If a limit is published, cite that product’s current terms. If it is not, record the limit as unverified and obtain a written answer rather than copying a threshold from a comparison article.
Decide From the Missing Output
Keep a free workflow if it produces the required outputs at an acceptable review burden. Consider a paid platform when a verified workflow gap, support requirement or measured integration cost justifies it. For some teams, retaining a free analysis tool beside a paid design platform is the sensible arrangement.
To evaluate SurgePV, bring that same representative project to a design-workflow demonstration. Review the documented design scope and confirm current commercial terms on the pricing page. A demonstration should answer your project questions, not substitute for engineering approval.
Frequently Asked Questions
Can professional installers use free solar software?
Yes, where the specific tool and supporting workflow meet the project’s requirements. OpenSolar documents design and sales workflows, while SAM documents engineering analysis. Evaluate equipment support, outputs and responsible review. There is no evidence here for a universal rule that professional use requires a paid licence.
Are permits free if the design platform is free?
Not necessarily. Platform access, generated diagrams, third-party plan sets, engineering stamps and application services are separate items. Ask which are included and which are charged separately. Confirm the requirements with the relevant authority before budgeting or promising an approval date.
When should a team move to paid software?
Move when a verified requirement or measured workflow benefit justifies the incremental cost. Examples include an output your present stack cannot produce or a support arrangement your business requires. Avoid invented team-size thresholds, guaranteed payback periods and assumed sales improvements.
