PVsyst is a desktop application long used for photovoltaic yield simulation and a widely recognised reference for detailed performance reports. SolarSimPro takes on a wider job: it holds the whole chain — from drawing the site to the CAD file you hand the client — in a single model, in the browser. The difference is not in calculation accuracy but in scope.
SolarSimPro runs in the browser; it needs no installation, licence key or dongle. A team can reach the same project from different machines.
It draws the roof outline or fetches the land from its registry parcel reference, then generates the module layout itself, allowing for obstacles and slope.
The bill of materials is derived from the layout and multiplied by unit prices; payback, NPV and IRR come out of the same model.
Setting-out plan DXF, coordinate lists, KMZ and a client-ready report are produced directly.
Preparing a solar proposal runs through eight steps: defining the site, terrain analysis, module layout, shading analysis, yield calculation, bill of materials, cost and feasibility, and the deliverables. SolarSimPro produces all eight, and they all come out of the same model.
Desktop simulation tools go deep in the middle of that chain, in yield modelling. For the site setup at the start and the bill of materials and setting-out plan at the end you have to move to separate tools. In SolarSimPro there is no handover: change the module count and all eight steps update together.
The table below is not about which tool is “better”. It shows where and how the same job gets done in each. The two concentrate on different parts of the workflow.
| Step | In PVsyst | In SolarSimPro |
|---|---|---|
| Setup and access | Desktop application installed on Windows; runs with a licence key. | Opens in the browser; no installation, licence key or hardware dongle. |
| Defining the site | Site geometry and horizon profile are defined by the designer. | Draw the roof outline, or pull the parcel in by cadastral query. |
| Terrain data | Slope and orientation are supplied as design inputs. | Slope, aspect and contours are derived from the site itself. |
| Module layout | String and table arrangement is composed by the designer. | Generated automatically from obstacles, slope and setbacks; editable by hand. |
| Near shading | Detailed three-dimensional shading scene and loss modelling. | Ray-traced near shading with an hourly loss map. |
| Yield calculation | 8,760-hour simulation with a detailed loss diagram. | 8,760-hour simulation; PVGIS-SARAH3 irradiance data, PR and P50/P90. |
| Bill of materials | Handled as a separate exercise. | Derived from the layout and the DC capacity. |
| Cost and feasibility | Economic evaluation is treated as a separate step. | Unit-price database, cash flow, payback, NPV, IRR and net metering from one model. |
| Deliverables | Detailed technical simulation report. | Setting-out DXF, coordinate list CSV, KMZ and a client-ready report. |
The lower half of the table is what the proposal is made of: materials, cost, feasibility and CAD output. In SolarSimPro these follow directly from the layout — change the module count and all four are recalculated, with nothing carried across by hand.
Installation, version drift and licence-key administration disappear. A new team member clicks a link and starts working; there are no updates to distribute.
Because the project lives in the cloud, a roof inspected on site and the calculation done at the office meet in the same file.
Without dropping your current tool, rebuild a completed project on the same assumptions and compare the results.
Preparing a proposal usually splits across tools: CAD for the boundary and layout, a simulation tool for yield, a spreadsheet for materials and cost, a word processor for the proposal itself. Data moves between them by hand.
The real cost is not in the first calculation but in the revision. When the client changes the module, or part of the roof turns out to be unusable, the whole chain is reworked: layout, materials, cost, yield, payback and the delivery files.
SolarSimPro keeps those steps in one model. Change the module count and the bill of materials, cost, yield and feasibility update together; the DXF and the report are regenerated from the same model. That is why the more useful comparison is not “which one calculates more accurately” but “how many steps does one revision take”.
For the entire proposal cycle, yes. Drawing, layout, ray-traced shading, the 8,760-hour yield calculation, bill of materials, cost, feasibility and the setting-out DXF all come out of one model in SolarSimPro. The only case that sends you back to another tool is a specification naming a particular software's report.
No. A current browser is enough; there is no installation, licence key or dongle.
Yes. The setting-out plan exports as DXF, coordinate lists as CSV and the 3D model as KMZ.
There is. Register and request a demo; once approved, your time starts the moment you first open the application.
With the assumptions aligned, annual yield figures come out close to each other. The remaining difference comes from the irradiance data source and the level of detail in the loss model. When comparing, make sure you use the same module and inverter model, the same tilt and azimuth, the same loss terms and the same meteorological period.
From the PVGIS-SARAH3 satellite-derived database. Reports typically use the average of 19 weather years between 2005 and 2023. The calculation starts from horizontal irradiance and is transposed to the module plane; shading, incidence-angle and cell-temperature losses are then applied in sequence.
Near shading is ray-traced: neighbouring rows, roof obstacles and surrounding volumes are evaluated hour by hour, producing an hourly loss map. The result feeds directly into the yield simulation rather than being applied as a separate correction factor.
Yes. Consumption profile, tariff and net metering rules are part of the feasibility model; payback period, NPV and IRR all come from it. You can save your own unit prices to the database and reuse them as defaults on later projects.
To rebuild a finished project in SolarSimPro you only need to redefine the site; drawing the roof outline or running a cadastral query keeps that step short. Once the module model and loss terms are aligned you can run the comparison on day one.
Rebuild a finished site and put the results side by side. Runs in the browser, no installation.