Commercial Solar

Designing Solar Around Vents, Plant and Shading

Guide · Commercial solar & battery · ~5 min read

Commercial roofs are rarely a clean sheet. Between exhaust vents, HVAC plant, walkways and neighbouring structures, a good solar design is as much about what you work around as what you install.

Why Roof Obstructions Matter

Every commercial roof carries its own mix of obstacles: exhaust vents, skylights, air conditioning plant, cable trays, aerials and safety walkways. Each one takes up space and can cast shade that moves across the day and the seasons.

The goal isn't to cram in as many panels as possible. It's to place panels where they'll actually produce, and to design the electrical layout so a shaded corner doesn't pull down the panels around it.

• Rooftop plant (HVAC, extraction fans, condensers)
• Vents, flues and skylights
• Walkways, handrails and maintenance access
• Aerials, cabling and lightning protection
• Parapets and neighbouring buildings that shade at certain hours

How Shading Actually Behaves

Shade isn't static. A vent that casts a small shadow at midday can throw a long one in the morning or late afternoon, and the winter sun sits lower so shadows stretch further. A proper design accounts for the sun's path across the whole year, not just a single moment.

The effect of shading also depends on how panels are wired together. With older string setups, shade on one panel can drag down every panel on that string. That's why the layout and the electrical design have to be planned together, not in isolation.

Design Techniques That Keep Panels Earning

There are several practical ways to work around obstructions while keeping output high. The right mix depends on your roof, your loads and your budget—so these are options we weigh up during a site review, not a one-size-fits-all recipe.

• Set clearance zones around vents and plant so shadows fall on gaps, not panels
• Group panels into strings that share similar shading conditions
• Use MPP tracking and, where it stacks up, panel-level optimisers or microinverters to isolate shaded panels
• Orient rows to suit the roof's real geometry rather than forcing a grid
• Leave clear maintenance access to plant so technicians don't tread on the array

Access, Safety and Future Servicing

A rooftop still needs to be serviced after the panels go on. Air conditioning units, vents and exhaust fans all require ongoing maintenance, and your solar layout shouldn't box them in.

Because ATI runs an in-house team rather than subcontractors, we plan walkways, fall protection and service corridors as part of the design. That keeps your facility maintenance workable and keeps everyone compliant when someone's up there down the track.

Making Every Square Metre Count

On tight or complex roofs, the panels you can install matter even more. Pairing a well-designed array with battery storage and AI-driven energy arbitrage means the energy you do generate goes further—charging when power is cheap and discharging or exporting when it's dear.

We've delivered this approach across a range of sites, from a 415kW rooftop at DB Santasalo in Bulli to work at Garmin, Goldschmidt, a Hunter Valley vineyard and Kingswood. Every one had its own roof quirks, and the design was built around them.

Start With a Site Review

You can't design good solar around vents, plant and shading from a satellite image alone. The real answers come from measuring the roof, mapping the shadows through the day and checking access and structure.

If you've got a cluttered or complex commercial roof and you're not sure how much of it can work, a site review is the practical first step. We'll walk the roof, model the shading and show you what's realistic—no assumptions, no invented figures.

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