New Zealand is a mountainous country at temperate southern latitudes, and both halves of that sentence change shading analysis. Invercargill sits at 46 degrees south, further from the equator than Toronto is from it. And terrain, not buildings, is frequently the dominant obstruction. Software configured for a flat suburban lot in a warm market answers the wrong question here.
Direct answer. The best solar shading analysis software in New Zealand is PVsyst, because it takes a far-horizon terrain profile and a near-field 3D scene as separate explicit inputs, which is what a hilly country at 37 to 46 degrees south requires. SurgePV covers the same hourly modelling alongside the layout and single-line diagram for the electrical certification pack.
TL;DR
- Terrain shading is the distinctive New Zealand problem. Model the horizon profile, not just the roof.
- Arrays face north. Any tool defaulting to a northern hemisphere sun path is wrong by half a year.
- Buy-back rates are low, so self-consumption drives value and midday shading costs less than morning or evening shading.
- AS/NZS 5033 governs the installation and the electrical worker carries the certification.
- Latitude range is wide, from 35 to 47 degrees south. A Northland assumption fails in Southland.
What New Zealand Actually Changes About Shading Analysis
Terrain is the obstruction. A large share of New Zealand housing sits in valleys, on hillsides, or with a ridge to the north. At Wellington or Dunedin latitudes a hill a kilometre away can remove the first and last hours of winter generation entirely. This is far-horizon shading, and it is invisible to any tool that only models the building and its immediate surroundings. A New Zealand site assessment that carefully models the roof and assumes a flat horizon has missed the larger effect on a great many sites.
The sun is in the north. Southern hemisphere sun path is not a cosmetic setting. Any tool or spreadsheet imported from a northern market and not properly reconfigured will place shadows on the wrong side of every obstruction. Established platforms handle this correctly, but locally built calculators and inherited spreadsheets are a real source of error.
Low buy-back changes what shading costs. With export rates well below retail, the value of generation depends heavily on whether it coincides with household load. Morning and evening shading, which removes generation during the periods most likely to be self-consumed, is worth more than midday shading on a system already exporting surplus. A shading study that reports only annual kWh loss misses this entirely, and the correct output is a loss profile against the load, not a single number.
Latitude range is wide. Kaitaia to Invercargill covers roughly twelve degrees. Inter-row pitch and winter shadow assumptions derived in Auckland do not transfer to Otago.
Certification sits with the electrical worker. AS/NZS 5033 governs the installation and the registered electrical worker signs it off. Shading is an engineering input rather than a prescribed compliance measurement, so tool choice is an accuracy question.
The 7 Platforms Ranked for New Zealand
| Platform | Best for | Far-horizon terrain profile | Southern sun path | Price per seat per year |
|---|---|---|---|---|
| PVsyst | Terrain and detailed studies | Yes, explicit | Yes | ~$500 USD |
| SurgePV | Shading plus design and SLD | Yes | Yes, 8,760-hour | $1,299 to $1,899 USD |
| OpenSolar | Residential volume | Limited | Yes | $0 plus transaction fees |
| HelioScope | Commercial rooftop | Limited | Yes | ~$1,188 USD |
| Aurora Solar | Complex roof geometry | Limited | Yes | $1,908 to $3,108 USD |
| SketchUp plus Skelion | Bespoke terrain modelling | Manual | Manual | ~$700 USD plus plugin |
| SAM (NREL) | Sensitivity studies | Yes | Yes | Free |
PVsyst is the right default for any site with terrain in view. It imports a horizon profile and models near-field obstructions separately, then reports both effects independently in the loss diagram. See PVsyst price and our PVsyst loss diagram guide.
SurgePV runs 8,760-hour shading and carries the same model into string design, the single-line diagram, and DWG export.
OpenSolar works for flat-site residential volume where terrain is not a factor, and is free at the seat.
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SurgePV runs 8,760-hour shading against terrain and near-field obstructions on a southern hemisphere sun path, then carries the same model into string design and DWG export.
Book a free SurgePV demo →No credit card. 20-minute walkthrough on one of your own projects.
What a New Zealand Shading Deliverable Has to Contain
- Far-horizon profile covering terrain, surveyed on site or taken from an elevation dataset.
- Near-field 3D scene covering the building, neighbours, and vegetation.
- Hourly shading loss with monthly breakdown, winter months explicit.
- Loss profile against the load, not just annual kWh, because self-consumption drives the value.
- Inter-row pitch derivation for ground-mount, against the specific site’s winter sun path.
- Per-string loss table identifying positions worth excluding.
- Battery interaction where shading shifts generation away from the evening peak.
Item 4 is the one that changes the recommendation. On a low buy-back tariff, a shading pattern that removes midday export costs the customer far less than one that removes the morning, and a study reporting a single annual figure cannot tell them apart.
Pricing in New Zealand Dollars
| Stack | USD per year | Approx. NZD at 1.65 | Covers |
|---|---|---|---|
| OpenSolar | $0 plus fees | Transaction-linked | Residential shading and proposal |
| PVsyst | ~$500 | ~NZ$825 | Terrain and detailed shading |
| HelioScope | ~$1,188 | ~NZ$1,960 | Commercial layout and shading |
| SurgePV | $1,299 to $1,899 | ~NZ$2,143 to NZ$3,133 | Shading plus full design |
| Aurora | $1,908 to $3,108 | ~NZ$3,148 to NZ$5,128 | Sales-grade shading plus proposal |
Exchange rate is illustrative.
What Most New Zealand Installers Get Wrong
They model the roof and ignore the hill.
On a Dunedin or Wellington site with rising ground to the north, terrain can remove more winter generation than every near-field obstruction combined. Yet the standard site assessment measures the chimney and the neighbour’s tree and treats the horizon as flat. Capturing the horizon profile takes an instrument and twenty minutes on site, or a terrain dataset and less than that, and on a hilly site it is the single highest-value input in the whole study.
The second mistake is quoting shading loss as one annual number on a low buy-back tariff. The customer’s return depends on when the loss falls, not how much of it there is, and a study that cannot distinguish a lost morning from a lost midday is not answering the commercial question.
When Software Is Not the Answer
If the array cannot go where the shading model wants it because of wind loading or roof structure, that is engineering rather than modelling. AS/NZS 1170.2 wind loading governs mounting design and is a separate deliverable.
Our solar civil and structural engineering team produces wind-load and mounting designs delivered as STAAD Pro report calculations, with solar rooftop detailed engineering design for the construction pack. See the sample design pack.
Conclusion
- Survey the terrain horizon. On hilly New Zealand sites it outweighs every near-field obstruction.
- Report the loss profile, not just the total. Low buy-back means timing decides the value.
- Derive pitch for the actual latitude. Auckland assumptions fail in Southland.
In this country series: solar software in New Zealand, best solar design software in New Zealand, best solar proposal software in New Zealand, Pvsol review. Tool deep dives: Pvcase review, Pvsyst review.
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Disclosure and accuracy note
Commercial relationship. Heaven Designs and SurgePV are part of the same group. Treat our recommendation of SurgePV as a vendor making its own case, not an independent verdict. We have tried to describe every other product fairly, and to say plainly where a competitor is the better choice.
Pricing. All prices are indicative, compiled from public sources when this page was written. They vary by tier, region, contract term and exchange rate, and change without notice. Several vendors quote rather than publish, and some price in currencies other than the US dollar, so a converted figure moves with the exchange rate. Confirm current pricing with the vendor before you decide anything.
Trademarks and corrections. All product names and trademarks belong to their respective owners, and are used here for identification and comparison only. Their use does not imply affiliation with or endorsement by those companies. If anything here is out of date or wrong, tell us and we will correct it.
FAQ
What is the best solar shading analysis software in New Zealand? PVsyst, because it handles a far-horizon terrain profile and a near-field scene as separate explicit inputs. SurgePV where the same licence also has to produce the layout and single-line diagram.
Why does terrain matter so much in New Zealand? Because much of the housing stock sits in valleys or on hillsides. A ridge to the north can remove the first and last hours of winter generation, and horizon shading of that kind is invisible to tools that only model the building.
Do northern hemisphere tools work in New Zealand? Established platforms handle the southern sun path correctly. Imported spreadsheets and locally built calculators are where the error appears, placing shadows on the wrong side of every obstruction.
How do low buy-back rates change the analysis? They make timing matter more than volume. Shading that removes generation the household would have used itself costs far more than shading that removes surplus being exported at a low rate.
Is a specific shading method required in New Zealand? No. AS/NZS 5033 governs the installation and the registered electrical worker certifies it, but shading is an engineering input rather than a prescribed measurement, so tool choice is an accuracy question.
How much does solar shading analysis software cost in New Zealand? From NZ$0 with OpenSolar’s transaction model to roughly NZ$5,128 for Aurora’s higher tiers. Full math is in our solar design software pricing breakdown.
Related: the wider tool decision is in best solar design software in New Zealand, and the method in how to do shadow analysis for solar rooftop projects.
