Solar Shading Analysis Tools: Software vs Hardware

Distant hills, a neighbor’s chimney and a tree on the roof each need a different shading tool. This guide sorts horizon tools, 3D simulation software and on-site devices by the shade they can find, and lists the price each vendor publishes.

Last updated: November 2026.

SurgePV publishes this guide and sells one of the tools compared. The table lists what each vendor publishes on its own site and does not score accuracy, because the accuracy figures vendors publish are self-reported and cover whole simulations, not shading alone.

Which Type of Shading Tool Fits the Job

Shade comes from two places, and each needs a different tool. PVsyst’s documentation separates them: far shadings come from objects far enough away to be described by a horizon line (roughly more than ten times the PV field size), and near shadings come from nearby objects that cast visible shadows on the array and need a detailed 3D description of the system and its surroundings (PVsyst documentation).

• Hills, mountains, a distant skyline: a horizon profile is enough. PVGIS offers this free, with a calculated terrain horizon or your own uploaded horizon file.
• Chimneys, parapets, dormers, neighbouring buildings, trees: use 3D simulation software, where you model the obstruction and the tool calculates the shadow for each hour.
• A roof you cannot model from imagery: measure on site with a device such as the Solar Pathfinder or the Solmetric SunEye-210, then enter the result in your design software.

This is a guide to tool types, not a ranking. Which one fits depends on the site, the project size and how much of the design you want in one workflow.

Solar Shading Analysis Tools Compared

Prices below were read from each vendor’s own page on 28 October 2026. Confirm them before you buy, and confirm taxes and renewal terms in a written quote.

Arithmetic check for the annual prices: USD 135 x 12 = USD 1,620 and USD 220 x 12 = USD 2,640, which match the annual totals both vendors print. HelioScope’s monthly plan costs USD 159 x 12 = USD 1,908 over a year, so its annual plan saves USD 288, the same saving Aurora prints for Basic.

What the Vendors Say About Shade

PVsyst. The documentation says near-shading treatment is “much more complex than far shadings” and is computed at each time step, with the beam, diffuse and albedo components treated differently. For electrical losses it offers a rough “according to strings” estimate, which it describes as an upper limit, and a detailed calculation from exact module positions in the field.

HelioScope and Aurora. Both list the shade-related features by plan, so check which plan holds the one you need. HelioScope’s page puts LIDAR-assisted modeling and AI-based obstruction detection in Pro. Aurora’s page puts LIDAR-assisted modeling and bankable shade reports in Premium. HelioScope’s page states production estimates within 1% of PVsyst. That is a claim about the whole simulation, not about shading alone, and Aurora’s pricing page gives no accuracy figure.

PVGIS. The manual describes the horizon option as covering shade from nearby hills or mountains. The default is the built-in horizon; you can also upload your own as a text or CSV file with one horizon height in degrees per line, and most PVGIS tools plot the horizon with the results.

Solar Pathfinder. The vendor describes a non-electronic unit that shows shade over sunpath diagrams, with a diagram chosen for your latitude band. It is a measurement tool, not a simulation, so the result still goes into design software for yield.

Solmetric SunEye-210. An electronic tool that reports annual sunpath, monthly solar access and obstruction elevation. Its desktop software exports files for PVsyst, PV*SOL and other design programs.

How Shading Cuts Output

Panels wire their cells in series, and the weakest cell sets the current. PVEducation explains that when one cell has lower current than the others, the cell is driven into reverse bias, and a bypass diode across a group of cells gives the current a path around it (PVEducation: bypass diodes). In practice bypass diodes sit across groups of cells, not single cells.

That is why shading tools report two kinds of loss. PVsyst defines the shading factor as the ratio of shaded area to total sensitive area, then calculates irradiance losses and electrical mismatch losses separately. A tool that reports only shaded area leaves out the electrical part. Module-level power electronics change how that loss spreads through the system; see the glossary entries on MLPE and bypass diodes.

Shade also moves with the sun. A shadow that is absent at noon in June can cover part of the array in the morning in December, so run the simulation for the full year, not one day.

How to Run a Shading Analysis

1. Collect the site geometry. Roof outline, roof pitch and the position and height of every obstruction: chimneys, vents, parapets, nearby buildings and trees. A drone site survey is one way to capture this when imagery is out of date.
2. Pick the method. Horizon file for distant terrain, a 3D model for nearby obstructions, an on-site device where the roof is hard to model.
3. Run an annual simulation. Read the loss by month and by roof face, not only the yearly total.
4. Change the layout or the electrical design. Move modules off the worst areas, change string groupings, or consider module-level electronics where shade is unavoidable.
5. Check on site. Before installation, confirm that the obstructions in the model still exist and that the dimensions match.

For the method behind each step, read the shading analysis guide. For a quick check on one address, use the shading analysis tool.

Where SurgePV Fits

SurgePV’s shadow analysis runs an 8,760-hour annual shade simulation, lets you model trees, buildings and chimneys, and shows color-coded irradiance maps by roof surface. The same page says result quality depends on the accuracy of the site model and the assumptions you configure. It also supports P50 and P90 yield inputs, and says lenders and investors decide for themselves whether an output meets their requirements.

Shading sits next to roof modeling, array layout, yield and financial modeling and proposals in one workflow. The subscription is priced per user per year, and access is through a guided demo. SurgePV does not publish customer outcomes for shading, so test it on one of your own projects.

Common Mistakes

• Leaving the default “no shading” setting. Build the obstructions into the scene before you trust a yield number.
• Using one tool for every kind of shade. A horizon file does not describe a chimney.
• Checking one day. Run the full year so winter and summer shadows both count.
• Reading only the shaded-area share. Ask the tool for the electrical loss as well.
• Skipping the site check. Imagery goes out of date; trees grow and buildings go up.

For more on methods, see the shading knowledge hub, and for the wider picture of sunlight data see the irradiance guide.

Sources

• PVsyst documentation, Shadings
• PVsyst, shop
• European Commission JRC, PVGIS 5 user manual and PVGIS tool
• HelioScope, pricing
• Aurora Solar, pricing
• Solar Pathfinder, product page, tripod and case package and homepage
• Solmetric, SunEye-210 Shade Tool
• PVEducation, Bypass diodes
• SurgePV, shadow analysis and pricing

Frequently Asked Questions

What tools are used for solar shading analysis?

Three kinds. Horizon tools such as PVGIS read distant terrain shade. 3D simulation software such as HelioScope, Aurora Solar, PVsyst and SurgePV models nearby buildings, trees and roof obstructions in a site model. On-site devices such as the Solar Pathfinder and the Solmetric SunEye-210 record shade at the spot where the array will go.

What is the difference between geometric and electrical shading loss?

Geometric shading is the share of the array area that is shaded. Electrical loss is the energy actually lost. In a series string the weakest cell sets the current, so a small shaded area can cost more energy than its share of the area. PVsyst reports irradiance losses and electrical mismatch losses separately.

Is PVGIS enough for a shading analysis?

PVGIS is free and uses a horizon profile, either its calculated terrain horizon or one you upload, to estimate shade from hills and mountains. It does not model a chimney, a neighbouring building or a tree on your roof, so use a 3D tool or an on-site device for those.

What is a horizon profile in solar design?

A horizon profile lists the height angle of the skyline in each compass direction. PVGIS accepts it as a text file with one horizon height per line, and PVsyst uses a horizon line for far shadings. It suits objects far from the array, not nearby roof obstructions.

How much do shading analysis tools cost?

Published prices differ by type. HelioScope Basic is USD 159 a month or USD 1,620 a year per licence, and Aurora Solar Basic is USD 159 a month or USD 1,620 billed annually. The Solar Pathfinder unit is USD 299 and the Solmetric SunEye-210 has a base price of USD 2,195. PVGIS is free. SurgePV is USD 1,899 per user per year for one seat. Confirm current prices with each vendor.

Do I need a site visit if I use software?

The model is only as good as the site data you give it. Check that obstructions in the imagery still exist and that roof dimensions match, then confirm on site before you finalise the layout.