Solar PV Design Software Compared: PVsyst, PV*SOL, HelioScope and More

Updated 23 October 2026 · SEO Dons Editorial

What is each tool for?

The descriptions below come from each maker's own pages, read on 22 October 2026, in alphabetical order. They describe what the makers say about their own products. They are not rankings or endorsements, and nothing here compares prices.

Tool	What the maker's page says	Page date
HelioScope	Models rooftop, carport and ground-mount solar together with storage, from design to financials, in one solution	2026 home page; help articles 2025 and 2026
OpenSolar	Auto Design works out pitch, azimuth and shading and generates a bill of materials; designs feed a customer proposal; can design commercial systems	Help articles 2026
PV*SOL premium	Professional software for 3D design and simulation of PV systems; reports include a tabular energy balance of gains and losses	No date shown
PVGIS	European Commission web application giving solar radiation and PV energy production data for a place	Version 5.3
PVsyst	PC package for the study, sizing and data analysis of complete PV systems, with preliminary and detailed project modes	Version 8.1 documentation
SolarEdge Designer	Design tool with auto-stringing, tree shading, simulation, financial analysis and proposal tools	Release note, February 2022

The SolarEdge row rests on a February 2022 release note, because the company's main Designer pages could not be read automatically. Treat it as dated and check the current tool.

Where does each tool get its weather data?

HelioScope: its help centre (updated 21 July 2026) lists ground data from NREL typical-year files and satellite files including Meteonorm, plus a SolarAnywhere integration. A separate article explains uploading PVGIS weather files.
OpenSolar: both of its energy calculators use typical meteorological year (TMY) data, and a Weather Dataset setting selects regional weather files.
PV*SOL premium: Meteonorm 9 for any location worldwide (data period 2001 to 2020), with PVGIS, Solcast and SolarAnywhere available as providers.
PVGIS: its PVGIS-SARAH3 radiation database, which covers 2005 to 2023 for UK locations in version 5.3.
PVsyst: imports from many providers, including PVGIS typical years, Solcast and SolarAnywhere. For Meteonorm, PVsyst describes the hourly values as synthetic data built from monthly values.
SolarEdge Designer: the release note read does not name a weather source.

The choice matters. PVsyst's own comparison finds big discrepancies between databases and says it is very difficult to tell which suits a given location, although sources typically agree within 10% of their mean.

How does each tool model shading?

HelioScope: three sources, which are row-to-row shading, obstruction shading from drawn objects and an uploaded horizon file. Its help centre says a horizon profile is less precise than drawn obstructions for nearby trees and buildings, and that without optimisers or microinverters shading also brings mismatch losses.
OpenSolar: it depends on the calculator. The older PVWatts calculator needs shading losses entered manually, while the System Advisor Model (SAM) calculator applies hourly shading from a 3D scene.
PV*SOL premium: calculates shading from 3D objects.
PVGIS: a horizon, built in or uploaded, for shadows from nearby hills or mountains. It does not read roof obstructions.
PVsyst: a horizon for distant objects and a detailed 3D scene for near objects.
SolarEdge Designer: a tree shading feature, drawn from tree dimensions, as of the 2022 release note.

On a commercial roof with plant, parapets and neighbouring buildings, the useful question is whether the shading came from a scene of that roof. The PVsyst report guide shows where that appears.

Does the tool model the building's own demand?

This decides whether a report gives a yield figure or a bill-saving figure. The pages read say:

HelioScope: accepts consumption files with interval data at 60, 30 or 15 minutes, or monthly consumption typed in, with missing months filled automatically (articles updated 3 August 2026).
OpenSolar: takes the annual consumption, usage patterns and utility tariff, and lists whether a battery is included and how it charges and discharges among the factors behind its financial figures (updated 5 May 2026).
PV*SOL premium: names self-consumption, battery storage and electric vehicles among what it calculates.
PVsyst: counts energy used on site in its performance ratio when the installation accounts for self-consumption.
PVGIS: assumes all the PV energy is sent to the grid or used for other purposes, so it holds no demand model.

For a business, the sizing guide explains why half-hourly meter data should be the basis rather than a monthly or annual figure.

Which tools show P50 and P90?

PVsyst documents a P50-P90 tool for annual yields. HelioScope's help centre says a typical-year weather file gives a P50 and that a P90 needs a multi-year weather file, so a custom or single-year file cannot produce one. The pages read for the other tools do not describe a P90 feature, so ask the designer how a cautious figure would be produced.

What should a buyer ask the designer for?

The tool name and version, and for OpenSolar which energy calculator was used. Its help article says some losses are hard-coded within the chosen calculator.
The weather source, period and file type, typical year or single year.
The demand data used: half-hourly meter data, or a monthly or annual figure.
The shading scene: horizon and near objects, as a printout or image that matches the roof.
The loss assumptions, including soiling, mismatch, wiring, availability and degradation. PVGIS's 14% default is a useful yardstick for the total.
The module and inverter files used, with the datasheet versions.
The P50 and, where a cautious number is wanted, the P90 with the uncertainty inputs behind it.
The model file or an export that another competent person can open and check.

Put the answers next to each other in the quote comparison checklist, and see the guide to system losses for what the loss lines mean. The commercial PV systems guide covers the components behind the model, and readers who want a roof looked at against these checks can send an enquiry through the quote form.

Sources

PVsyst SA, PVsyst 8.1 documentation: Overview; Known format import; Provider comparison; Shadings; P50 - P90 evaluations; Performance ratio, checked 22 October 2026, no date shown.
Valentin Software: PV*SOL premium, checked 22 October 2026, no date shown.
HelioScope, an Aurora company: home page; Weather Data Sources (updated 21 July 2026); Uploading International Weather Files from PVGIS (8 July 2025); Shade Modeling (8 July 2025); Horizon Shading (8 July 2025); Creating a P50 and P90 (updated 14 July 2026); How to Configure Consumption Details and How to Upload Consumption Files (both updated 3 August 2026), checked 22 October 2026.
OpenSolar: How is Output Calculated in OpenSolar? (updated 18 February 2026); How to adjust your simulation settings (updated 13 April 2026); Auto Design; How OpenSolar calculates financial savings (updated 5 May 2026), checked 22 October 2026.
SolarEdge: SolarEdge Designer - What's New (release date February 2022), checked 22 October 2026.
European Commission Joint Research Centre: PVGIS 5 user manual and a PVGIS 5.3 PVcalc run, checked 22 October 2026.

Common questions

Is PVGIS enough to design a commercial system?

It works as a cross-check rather than a design. PVGIS gives energy and sunlight for a place and a fixed layout, with a horizon for distant hills or mountains and a default 14% loss allowance. It does not read the obstructions on a particular roof.

Why can two reports for the same roof differ?

Weather data, the shading method and the default losses can all differ, and PVsyst's own comparison shows big discrepancies between weather databases. The fix is to compare the stated inputs, not just the final kWh.

What do PVWatts and SAM mean in an OpenSolar design?

They are the two energy calculators in OpenSolar. Its help article says PVWatts was the default calculator from OpenSolar's launch in 2019 and that SAM was added in July 2020 with 3D shading and component-level losses. Ask which one the design used.