Picking the right mounting option for your solar PV system

One of the first choices you’ll need to make when planning a solar PV system isn’t about inverters or batteries. It’s about where the panels should go. For most projects, the big three are rooftop, ground mount, or carport.

Each option has trade-offs. Some are more cost-effective, others offer more flexibility. And some come with hidden problems that won’t be obvious until you’re up to your neck in structural drawings or trenching costs. We’ve done all three, and the right choice always depends on the site.

Rooftop solar – often first pick, but not always the winner

Most people start with the roof. It’s already there, it’s not being used, and in theory, it’s the cheapest place to mount PV. If the structure is solid, and the aspect and orientation reasonable, rooftop systems are the obvious choice.

But in practice, many roofs are less than ideal. Complex layouts with chimneys, air vents and aircon units limit usable space. Roofs may face multiple directions or have inconsistent pitch. Older buildings might need roof reinforcement before they can carry a PV load. And in many cases, safe access is a headache. Think of affordable housing complexes with multiple walk-up four-storey blocks – installing safe cat ladders may not be feasible, and routine maintenance turns into an inconvenient and expensive scaffolding exercise.

Maintenance is also an issue: if there’s a major roof repair in five years, you may need to remove the entire PV system to do it.

That said, when the roof is in good condition and accessible, rooftop PV is usually the cheapest and fastest to deploy.

Ground mount – flexibility and scale if you’ve got the land

If there’s spare land nearby – especially open veld, unused parking areas, or non-productive ground – a ground mount system can make sense. You get full design control: optimal panel angles, tidy cabling, and an easy-to-maintain layout. It’s also easier to expand the system later.

The catch is cost. Ground mount systems need mounting structures, foundations, trenching, and fencing. The capex is higher, and you’re dedicating land that might one day be needed for operations or expansion.

In rural or industrial settings where land is plentiful and energy loads are high, ground mount PV delivers strong long-term returns. In cities or tight sites, it’s usually off the table.

Carports – for when shade and visibility matter

Carport-mounted solar systems do double duty: they generate energy and provide shaded parking. If you’re running a shopping centre, office park, or corporate HQ, this can be a visible and useful sustainability feature.

But they’re not cheap. A carport is essentially a steel building, and it needs to meet both structural and electrical standards. Design complexity (lighting, signage, drainage) adds more cost. Unless you need the shade or are chasing green PR credits, carports rarely beat rooftop or ground mount systems on R/kWh.

Quick comparison – what you’re likely to spend

As a rough guide, rooftop solar is typically the most affordable, coming in between R9.00 and R11.00 per installed watt (excluding VAT), assuming the roof is in good condition and largely unobstructed.

Ground-mounted systems tend to be more expensive, usually ranging from R11.00 to R13.50 per watt, depending on how much civil work, fencing and trenching is involved.

Carports sit at the premium end of the spectrum, often costing between R13.50 and R16.00 per watt – justifiable if you're also solving for covered parking or sustainability visibility, but hard to defend purely on energy yield.

There’s no best option – only what fits your site

We’ve had factories rule out rooftop early because of asbestos sheeting. We’ve seen grain mills go for ground-mount because soiling from dust made the roof a non-starter. We’ve also seen carports make sense on an elite golf course where shaded parking and aesthetics were a priority.

That’s why we always start with the site: structure, shading, grid layout, long-term plans. We model each scenario to see what delivers the best return per rand over time.

Our take

Most solar providers will push what they’re set up to sell. At Decentral, we don’t come with a preferred structure. We come with an open spreadsheet and a clean site plan.

Let’s work with what your site offers – roof, veld or parking lot – and build the solar system that fits the shape of your business.