Best Solar Shading Analysis Software New Zealand 2026

If you are choosing solar shading analysis software for New Zealand work in 2026, start with two corrections that break imported tools before you have modelled anything. New Zealand is in the southern hemisphere. June is winter, December is summer, and the default array orientation is north, not south. Every northern-hemisphere template, spacing table and sun path diagram inverts both, and we still see the mistake in proposals produced by tools configured offshore. The second correction is economic. New Zealand has no national feed-in tariff, so what a customer earns for an exported unit is whatever their retailer chooses to pay, commonly 7 to 17 cents against a retail import price near 28 to 34 cents. A self-consumed kilowatt-hour is therefore worth roughly three times an exported one, which means a shading loss at 8am costs several times more than the same loss at noon. An annual shading percentage cannot express that. This guide ranks the ten tools New Zealand designers genuinely use for shading, priced in New Zealand dollars, starting with SurgePV at about NZ$2,180 per user per year and naming exactly where it loses.

Direct answer. The best solar shading analysis software for New Zealand in 2026 is SurgePV, at about NZ$2,180 per user per year on the 5-User Team plan, because it runs an 8,760-hour module-level simulation and joins the result to an imported half-hourly consumption file, so it values a shading loss at the customer’s own consumption hours rather than at a blended annual rate. For a lender-grade loss diagram, PVsyst at CHF 700 per user per year, roughly NZ$1,470, still wins, and it is worth saying plainly that this is cheaper than SurgePV. For a one-van installer doing three jobs a month, OpenSolar free is the honest answer.

This guide is written for registered electricians doing PV, installer principals and consulting engineers whose yield numbers are being challenged. If you want the physics without the New Zealand economics, read the global pillar on solar shading analysis software first. For the wider tool decision, our best solar design software in New Zealand ranking covers the full workflow.

Southern Hemisphere First: What Imported Tools Get Backwards

This section exists because the error is common enough to cost real money, and because no vendor will tell you their tool has it.

North is the sun-facing direction. An unshaded New Zealand array faces north. A tool that defaults a residential roof to south, or that scores a north-facing plane as poor, is running a northern-hemisphere azimuth convention. Check this in the first five minutes of any trial by laying an array on a simple gable and reading the reported annual yield on each face.

June is the worst month, not December. The winter solstice is 21 June. Every low-sun calculation, every worst-case shadow, every minimum row pitch derives from a June sun angle. A shading heat map that shows the deepest losses in December is describing a roof in Europe.

The sun tracks across the northern sky, so shadows fall south. A tall obstruction on the southern side of an array is close to irrelevant for most of the day. The same obstruction on the northern side is the whole problem. Designers trained on northern-hemisphere material reverse this instinctively, and it shows up as a survey that measured the wrong tree.

Morning sun comes from the northeast, evening from the northwest. That matters more here than it sounds, because it interacts with the economics below. The obstructions that shade a New Zealand array during the morning and evening peaks of household consumption sit to the northeast and northwest, and those are exactly the hours where a shaded kilowatt-hour is most expensive.

Why a Shaded Kilowatt-Hour Costs Three Different Prices Here

This is the angle that carries this page, and it is the reason a New Zealand shading tool is not the same purchase as a British or German one.

In a market with a fixed feed-in tariff, every kilowatt-hour the array produces is worth roughly the same regardless of when it arrives. A shading loss of eight percent costs eight percent of revenue. Simple, and an annual percentage is a sufficient answer.

New Zealand does not work that way. There is no national feed-in tariff. Retailers set their own buyback, commonly somewhere between 7 and 17 cents per kilowatt-hour in 2026, with some applying daily caps, tiered rates or a higher evening-peak rate. Meanwhile the customer buys power back at roughly 28 to 34 cents including lines charges and GST. So the value of a produced kilowatt-hour depends entirely on whether the household was using it at the moment it was produced.

That makes a shading loss a time-of-day question.

Work the arithmetic on a real job. Take a 6 kW north-facing Auckland array generating about 8,500 kWh a year, on a plan paying 12 cents buyback against a 30 cent import price. Now apply an eight percent shading loss, roughly 680 kWh.

Where the shading loss falls	What the lost energy would have been worth	Annual cost of the same 680 kWh loss
Entirely in midday export hours	12c per kWh buyback	~NZ$82
Split evenly across the day	Blended, roughly 18c	~NZ$122
Entirely in morning and evening consumption hours	30c per kWh avoided import	~NZ$204

The same array, the same obstruction geometry, the same eight percent. Two and a half times the financial impact depending only on when the shadow falls. And the third row is not a hypothetical: a tree or neighbouring house to the northeast shades the morning, which in a heating-dominated New Zealand household is exactly when the hot water cylinder and the heat pump are running.

An annual shading percentage cannot carry that distinction. Neither can a monthly one. The only thing that can is a half-hourly generation profile matched against a half-hourly load profile, which is why the deciding capability in a New Zealand shading tool is not the sky model. It is whether the shading output can be joined to a real consumption file.

This is practical, not theoretical. New Zealand retail metering is half-hourly and most retailers will supply a customer’s consumption history on request. A designer who asks for twelve months of half-hourly data before quoting can produce a savings figure the customer can verify against their own bills. A designer who does not is guessing at the most important variable in the model. Our shading loss and payback period glossary entries set out the underlying definitions.

Get your sizing sanity-checked. For a fast second opinion on array size, shading loss and payback before you commit to a layout, run the numbers through our free solar calculator or talk to our engineering team.

June Sun Angles From Auckland to Invercargill

New Zealand is long and thin, spanning roughly 34 to 47 degrees south, and the shadow geometry at the two ends is genuinely different. Solar noon elevation on the winter solstice is approximately 90 minus latitude minus 23.44, and the shadow multiplier is 1 / tan(elevation).

City	Latitude	21 June noon elevation	Shadow multiplier	3 m obstruction casts
Auckland	36.8S	29.7 degrees	1.75	5.3 m
Hamilton	37.8S	28.8 degrees	1.82	5.5 m
Wellington	41.3S	25.3 degrees	2.12	6.4 m
Christchurch	43.5S	23.1 degrees	2.35	7.0 m
Invercargill	46.4S	20.2 degrees	2.72	8.2 m

A three metre chimney throws five and a half metres of shadow in Auckland and eight metres in Invercargill at the best moment of the shortest day. That is a fifty percent difference within one country, and it means a national row pitch default is wrong at both ends.

Inter-row spacing, worked at both extremes. Take a 2.28 m module in portrait at 20 degrees tilt on a flat roof. The vertical rise is 2.28 x sin(20) = 0.78 m and its own horizontal projection is 2.28 x cos(20) = 2.14 m.

• Auckland (36.8S): clearance 0.78 x 1.75 = 1.37 m, so pitch near 3.5 m and a ground coverage ratio around 0.65.
• Invercargill (46.4S): clearance 0.78 x 2.72 = 2.12 m, so pitch near 4.3 m and a ground coverage ratio around 0.54.

That is roughly twenty percent more capacity on the same flat roof in Auckland than in Southland, from geometry alone. A tool that applies one national spacing rule underbuilds Auckland or overbuilds Invercargill, and on a commercial roof either error is expensive.

Winter is also when consumption peaks. New Zealand households heat in June and July, which are the months the array produces least. That double squeeze is why monthly reporting matters, and why a shading loss concentrated in winter hurts more than the annual figure implies. A tool reporting only annual kWh hides the worst part of the customer experience, and the customer discovers it in August with a phone call.

The 5-Point New Zealand Shading Bench

This is the framework we use before putting any shading tool in front of a New Zealand design team. Score each axis 1 to 10, out of 50. Nothing below 38 goes into production work.

1. Half-hourly value joining. Can it import a customer’s half-hourly consumption file and report the shading loss valued at self-consumption or export prices depending on the hour it falls in?
2. Southern hemisphere correctness. North-facing default, June as the low-sun month, shadows cast to the south, and spacing computed from the actual site latitude rather than a national default.
3. Diffuse handling. New Zealand’s maritime climate delivers a large diffuse fraction, so the tool needs a properly separated diffuse component and a sky view factor on partial obstructions rather than beam-only geometry.
4. Horizon capture and import. Measured fisheye capture or a terrain-derived horizon profile, not only satellite inference, which is weak on bush-clad and hillside sites.
5. Monthly and hourly reporting. Shading shown as a monthly and time-of-day shape rather than a single annual number, because that is the only form the economics can read.

Scores across the ten tools below: SurgePV 43, SolarPlus 38, PVsyst 38, OpenSolar 34, PV*SOL premium 36, HelioScope 32, Solmetric SunEye 34, Scanifly 30, PVGIS horizon import 29, Aurora Solar 27. The scoring is ours and it is opinionated. SolarPlus and PVsyst tying at 38 for entirely opposite reasons, one on tariff and dispatch modelling and one on physics, is the honest result.

Top 10 Solar Shading Analysis Tools in New Zealand Compared

Every vendor below is quoted in the currency it actually bills in. Approximate New Zealand dollar figures follow at roughly NZ$1.68 per US dollar, NZ$1.85 per euro and NZ$2.10 per Swiss franc, rates current at the time of writing. Hardware is one-off capital, shown separately.

#	Tool	Price (vendor currency, approx NZD)	Shading capability	Best for
1	SurgePV	US$1,299/user/yr (~NZ$2,180)	8,760-hr module-level shading joined to half-hourly load	Installers doing 5+ NZ jobs a month
2	SolarPlus	US$135 to US$450/mo per plan on annual pre-pay (~NZ$227 to NZ$756)	Shading into tariff and battery dispatch modelling	Solar plus storage shops
3	PVsyst	CHF 700/user/yr (~NZ$1,470)	Reference near-shading 3D scene plus horizon import	Lender due diligence and disputed yield
4	PV*SOL premium	EUR 845/named user/yr + VAT (~NZ$1,560)	Animated 3D shading walkthrough	Winning shading arguments in the lounge
5	OpenSolar	Core platform free	Adequate residential shading at zero entry cost	Solo and two-van residential installers
6	Solmetric SunEye 210	US$2,195 base, North America (~NZ$3,690)	Fisheye horizon capture at the array position	Bush-clad, hillside and rear-elevation sites
7	HelioScope	US$159/mo Basic, US$259/mo Pro (~NZ$267 to NZ$435)	Module-level 8,760-hr on C&I roofs, clean loss tree	Commercial rooftop consultancies
8	Scanifly	Not publicly listed	Drone photogrammetry into a shade-capable 3D model	Steep, aged or unsafe NZ roof stock
9	PVGIS horizon import	Free	Terrain horizon profile from elevation data	Valley, hillside and Southern Alps sites
10	Aurora Solar	Basic US$135/user/mo billed annually (~NZ$227), Premium US$220 (~NZ$370)	Residential shade capture inside a sales workflow	Groups already standardised on Aurora

The honest read: positions 1, 2 and 5 are what most New Zealand rooftop firms actually choose between. Positions 6 and 9 are inputs rather than products. Aurora at ten is a strong product ranked low for one reason, which is that its financial layer answers a United States question.

1. SurgePV

What it does best for New Zealand shading. SurgePV builds the 3D roof from a satellite address, detects chimneys, dormers, tank stands, neighbouring gables and tree canopies, then runs an 8,760-hour module-level simulation with bypass-diode physics and an anisotropic sky model that separates diffuse from direct rather than scaling one global figure. That last point matters in a maritime climate where a large share of annual irradiation arrives diffuse and a beam-only shading model misprices a partly obstructed roof in both directions.

The New Zealand-specific reason it heads this list is what happens after the simulation. The output is half-hourly, and it joins to an imported customer consumption file, so the tool values each shaded half hour at either the retail import price the customer avoided or the retailer buyback they lost, rather than at a blended annual rate. A shading loss falling at 8am on a June morning is reported as costing what it actually costs. Orientation defaults are southern hemisphere correct, spacing is computed from the site latitude, and the annual heat map colours every module by percent irradiance loss with a monthly breakdown behind it. The shadow analysis module is bundled on every paid plan rather than gated behind a tier.

Pricing. US$1,299 (about NZ$2,180) per user per year on the 5-User Team plan, so US$6,495 or about NZ$10,900 for five seats. A single Individual seat is US$1,899, about NZ$3,190 a year. Free trial, no credit card. Worth stating plainly: Aurora’s Basic plan at US$135 per user per month billed annually works out to US$1,620 a year, which undercuts a SurgePV Individual seat, and PVsyst at CHF 700 undercuts both.

Who it suits. Installers and EPCs doing five or more New Zealand designs a month, especially teams that already ask customers for half-hourly data.

Honest limitations. Four concrete ones. There is no maintained New Zealand retailer tariff library. The half-hourly valuation is only as good as the buyback and import rates your team enters, and when a retailer changes its export offer nobody at SurgePV pushes that change to you, which on a page about time-of-day valuation is the most damaging gap it has. Its horizon capture is satellite-derived, not measured, and New Zealand’s bush-clad sections, punga and mature pohutukawa are exactly the canopy types satellite inference handles worst, so awkward sites still want a SunEye reading, which it will import rather than generate. Brand recognition is thin against OpenSolar, which has been the Australasian residential default for years, so a designer joining your team probably knows the competitor’s interface and not this one. And it is not a CRM or job management tool, so the Certificate of Compliance paper trail and scheduling still live in a second system.

Book a SurgePV demo and bring a real site with twelve months of half-hourly data and a tree to the northeast, so you can test the time-of-day valuation on your own numbers rather than a showcase file.

2. SolarPlus

What it does best. SolarPlus treats design, tariff modelling, battery sizing and proposal as one continuous job, and its self-consumption and battery dispatch modelling is better than most cloud tools at this price. For shading specifically that matters because a battery changes the answer: a morning shading loss that would otherwise cost full retail price can be partly covered by stored energy, and SolarPlus is one of the few tools here that will actually show you the difference rather than leaving you to assume it.

Pricing. SolarPlus bills in US dollars, not Australian dollars, and it is a plan price rather than a per-seat one. Starter US$135 a month, Pro US$260 and Complete US$450 on annual pre-pay, or US$150, US$300 and US$520 billed monthly. At roughly NZ$1.68 to the US dollar that is about NZ$227, NZ$437 and NZ$756 a month. Enterprise is quote only.

Who it suits. Residential and small commercial shops selling solar with storage.

Honest limitations. The 3D roof modelling and shading engine are lighter than SurgePV, PVsyst or HelioScope, so complex multi-plane roofs and heavily treed southern sites need manual work and the geometry is where its score is lost. Tariff libraries are Australian-first, so New Zealand retailer plans are configured by hand. Ground mount is outside its scope and the interface carries visible legacy.

3. PVsyst

What it does best. PVsyst remains the reference for near-shading. Its 3D shading scene builds obstructions to real dimensions, its horizon file import accepts terrain and survey profiles, and its loss diagram separates near shading from horizon shading from electrical mismatch. Its diffuse and transposition modelling is unusually well suited to New Zealand conditions because every assumption is exposed and adjustable rather than baked in. When a bank or an independent engineer wants a second opinion on a Canterbury commercial project, the PVsyst loss diagram is the document they ask for.

Pricing. CHF 700 per user per year for a Professional licence, an annual subscription rather than a perpetual purchase, about NZ$1,470. Education is CHF 420 and Training/Research CHF 560. Group discounts run 5 to 20 percent by quantity. Five seats is CHF 3,500, roughly NZ$7,350, which is materially cheaper than SurgePV at five seats.

Who it suits. Consulting engineers, technical due diligence teams and anyone whose shading number will be argued about.

Honest limitations. Windows desktop only, a steep learning curve, and building a shading scene by hand takes an hour on a roof SurgePV models in a minute. For this page’s angle the decisive gap is that it has no retailer buyback logic and no half-hourly load joining, so it will tell you precisely how much energy the tree costs and nothing about what that energy was worth. Our PVsyst alternative guide sets out where the tradeoff sits, and Heaven Designs keeps a deeper solar design software resource centre for the engineering services view.

4. PV*SOL premium

What it does best. Valentin Software’s animated 3D shading walkthrough is the most persuasive customer-facing shading artefact any tool produces. When a homeowner in Titirangi insists the neighbour’s tree is not a problem, playing the June shadow sweep across their own roof ends the conversation quickly. The underlying simulation is trusted and self-consumption modelling is present and reasonable.

Pricing. EUR 845 per named user per year plus VAT for PVSOL premium, about NZ$1,560. Standard PVSOL is EUR 585. This is a user-based subscription, not a perpetual licence with a maintenance fee. Licences bought before 19 November 2024 remain usable indefinitely, but maintenance renewals ended on 1 October 2024. Five named users is EUR 4,225, roughly NZ$7,820, again cheaper than SurgePV at five seats.

Who it suits. Design-led firms that lose jobs to shading disputes rather than to price.

Honest limitations. Windows desktop only, no collaboration, no satellite roof capture so every job starts with manual modelling, no AS/NZS drawing output and no New Zealand retailer rate handling. Its self-consumption model works from a synthetic load profile rather than an imported half-hourly file unless you build one. Our PV*SOL alternative writeup has the detail.

5. OpenSolar

What it does best. OpenSolar is the most widely used design and proposal tool across Australasia, funded by hardware referral margin rather than seat licences, and its residential shading is adequate for a straightforward suburban roof at an entry cost of zero. For a one-van installer that removes the licence decision from year one entirely, and a large share of the New Zealand installer workforce already knows the interface.

Pricing. The core platform is free, for any number of users. From 16 April 2026 OpenSolar begins charging for API Access, billed per project on creation, and for Connectors, billed as a flat monthly fee. OpenSolar has not published those rates and they are geo-specific, so we are not going to put a number on a New Zealand seat. Free remains the honest description of the design and shading workflow itself, and that is cheaper than everything else on this page including SurgePV.

Who it suits. Solo installers and two-van outfits doing under five residential jobs a month.

Honest limitations. The New Zealand layer is thin: no retailer buyback table and a self-consumption model coarser than this market needs, which is precisely the axis that decides the value of a shading loss here. The economics steer you toward hardware partners, and from 16 April 2026 API Access and Connectors become chargeable at rates OpenSolar has not published, so a workflow built on data export carries an unknown future cost. Commercial rooftop exposes the ceiling quickly. Our OpenSolar alternative comparison covers the crossover point.

6. Solmetric SunEye 210

What it does best. A fisheye camera handset held at the array position that captures the actual horizon and overlays the sun path, returning monthly and annual solar access percentages. On a bush-clad section, a hillside site in Wellington or a rear elevation that satellite imagery renders poorly, it is measured evidence rather than modelled inference, and New Zealand has a lot of both site types.

Pricing. The SunEye 210 is a current product, not a discontinued one. Solmetric lists it at US$2,195 base for North America, about NZ$3,690, including a lifetime PV Designer licence. As of 2 August 2026 it is out of stock with a stated 10 to 12 week lead time, so plan the purchase ahead of a survey season. Solmetric has been a Fluke company since the acquisition announced on 12 September 2023.

Who it suits. Survey teams working treed, sloped or densely built sites.

Honest limitations. Lead time is the headline risk rather than availability. It is a capture device that gives solar access percentages, not module-level energy or time-of-day value, so it feeds a simulator rather than replacing one. Readings are position-sensitive, and one taken from the ground rather than the array plane describes a roof you are not building.

7. HelioScope

What it does best. Module-level 8,760-hour simulation with a loss tree engineers accept without argument. On a 400 kW warehouse roof in Penrose with rooftop plant and a parapet, it quantifies partial-shade mismatch properly rather than averaging it away.

Pricing. Basic US$159 a month or US$1,620 a year, Pro US$259 a month or US$2,640 a year, both for one user with a 10 project per month cap. Enterprise is quote only. That is about NZ$267 and NZ$435 a month, so roughly NZ$16,000 a year for five Basic seats.

Who it suits. Commercial and industrial consultancies whose deliverable is a yield report.

Honest limitations. No AS/NZS drawing output, no satellite roof capture, weak proposal tooling that forces a second licence, and no self-consumption engine worth the name. On a New Zealand commercial job where the deal turns on daytime load coincidence against a low buyback rate, that last gap is the one that matters. Read our HelioScope alternative comparison before committing seats.

8. Scanifly

What it does best. Drone photogrammetry converts a flight into an as-built 3D site model with real obstruction geometry, which then drives a shading calculation. On steep, aged or asbestos-era New Zealand roof stock where sending a surveyor up is the wrong call, that is a safety gain as well as an accuracy gain, and it captures tree canopy geometry far better than satellite inference does.

Pricing. Scanifly does not publish pricing. Every per-seat or per-project figure circulating in software directories is an unverified third-party estimate, so treat a quote from Scanifly as the only usable number.

Who it suits. Installers with difficult roof stock and an existing drone programme.

Honest limitations. Capture first and simulation second, so a defensible yield report still comes from elsewhere. New Zealand civil aviation rules and weather cut usable flying days below what the vendor’s United States material implies, and it produces no financial or tariff output at all. Our Scanifly alternative writeup covers the cheaper routes.

9. PVGIS Horizon Import

What it does best. A technique rather than a product, and under-used in New Zealand. The JRC PVGIS tool derives a terrain horizon profile from global elevation data and exports it in a format PVsyst and most serious simulators import directly. On a West Coast valley floor, a Wellington gully or a site under a Southern Alps ridge line, terrain horizon shading can cost several percent of annual yield, and no satellite roof model will see it because the obstruction is a mountain kilometres away. Confirm the irradiance dataset coverage for your coordinates before using PVGIS climate data itself, but the terrain horizon export is the part worth having.

Pricing. Free. Meteonorm sells a richer commercial equivalent.

Who it suits. Any engineer who already owns a simulator and works outside flat urban Auckland or Canterbury.

Honest limitations. Terrain horizon data knows nothing about buildings or trees, so it complements a near-shading model rather than replacing one. Resolution is coarse on short-range obstructions, and combining terrain horizon with a near-shading scene without double-counting requires care.

10. Aurora Solar

What it does best. Aurora’s shade capture inside a residential sales workflow is genuinely good, with mature roof plane detection that copes with New Zealand suburban housing stock and irradiance maps that present well to a homeowner.

Pricing. Basic US$135 per user per month billed annually, US$159 billed monthly. Premium US$220 annually, US$259 monthly. Enterprise is custom. Both Basic and Premium cover one user and 50 projects a month, and LIDAR modelling, bankable shade reports and battery modelling sit in Premium. Plan sets are a separately priced service rather than a plan inclusion, and site models start at US$9.99. At roughly NZ$1.68 to the dollar that is about NZ$227 and NZ$370 per user per month, so five Basic seats land near NZ$13,600 a year and five Premium seats near NZ$22,200. Note that Aurora Basic at US$1,620 a year is cheaper than a SurgePV Individual seat at US$1,899.

Who it suits. Larger residential operations arriving with Aurora templates and training in place.

Honest limitations. The financial layer is built around United States net metering and federal tax credit mechanics, neither of which exists here, so the tool will happily value every shaded kilowatt-hour identically. In a market where self-consumption is worth three times export, that is not a cosmetic gap, it is the gap this page is about. No AS/NZS output and per-seat monthly pricing that scales painfully. See our Aurora Solar alternative comparison.

Send us a disputed roof. If a customer or a funder is challenging your yield figure, send us the design and our engineers will return an independent shading and yield opinion within 48 hours. Request a review →

Pricing in NZD for a Five-Person New Zealand Team

Tool	Per seat (vendor currency)	Five seats per year (approx NZD)	What you get for shading
SurgePV	US$1,299/user/yr (~NZ$2,180)	~NZ$10,900	8,760-hr module-level shading joined to half-hourly load, heat map, horizon import
PVGIS horizon import	Free	NZ$0	Terrain horizon profile from elevation data
OpenSolar	Core platform free	NZ$0	Residential shading at no licence cost; API and Connector rates unpublished from 16 Apr 2026
PVsyst	CHF 700/user/yr (~NZ$1,470)	~NZ$7,350 before group discount	Reference near-shading scene and loss diagram
PV*SOL premium	EUR 845/user/yr + VAT (~NZ$1,560)	~NZ$7,820	Animated 3D shading walkthrough
Solmetric SunEye 210	US$2,195 one-off (~NZ$3,690)	~NZ$7,380 for two units	Measured fisheye solar access, lifetime PV Designer licence
SolarPlus	US$260/mo Pro, plan not seat (~NZ$437)	~NZ$5,240 for the plan	Shading into tariff and battery dispatch
HelioScope	US$159/mo Basic (~NZ$267)	~NZ$16,000	C&I module-level simulation
Aurora Solar	US$135/user/mo annual Basic (~NZ$227)	~NZ$13,600 Basic, ~NZ$22,200 Premium	Residential shade inside a US-shaped sales workflow
Scanifly	Not publicly listed	Not publicly listed	Drone capture into a 3D shade model

Read that table honestly and SurgePV is not the cheapest thing on it. PVsyst for five seats is roughly half the price, PV*SOL is close behind, SolarPlus bills a plan rather than seats, and OpenSolar’s core platform costs nothing at all. What the extra buys is the half-hourly valuation none of them do, and if you do not intend to use that, the cheaper tools are the correct purchase.

The comparison a New Zealand firm should actually run is not SurgePV against PVsyst. It is SurgePV plus free PVGIS horizon data plus one shared SunEye at roughly NZ$14,600 in year one against OpenSolar free plus a spreadsheet holding retailer rates by hand, which costs almost nothing and gets you a shading percentage with the time-of-day valuation missing entirely. At three residential jobs a month the free route is the correct answer, which we would say on a sales call.

Mistakes New Zealand Designers Make on Shading

1. 1
   Quoting an annual shading percentage. The same eight percent loss costs about NZ$82 a year if it falls in midday export hours and about NZ$204 if it falls in morning consumption hours. The percentage is identical and the deal is not.
2. 2
   Running a tool with a northern hemisphere default. South-facing defaults, December as the low-sun month and shadows drawn to the north are all wrong here, and they survive quietly because the annual number still looks plausible.
3. 3
   Not asking the customer for their half-hourly data. Retailers supply it on request, metering is half-hourly, and without it the most important variable in the model is a guess dressed as a calculation.
4. 4
   Applying one national row pitch. A 20 degree array needs about 3.5 m of pitch in Auckland and about 4.3 m in Invercargill. One default underbuilds the north or overbuilds the south by roughly twenty percent of capacity.
5. 5
   Using a beam-only shading model in a maritime climate. A large share of New Zealand irradiation arrives diffuse, so an obstruction removes sky dome rather than only sunbeams, and a tool without a sky view factor misprices a partly shaded roof.

The wider set of workflow errors is covered in our writeup on common mistakes EPC companies make in rooftop solar. On the inverter side of a shading-driven regrouping decision, our sister engineering team’s dual MPPT versus single MPPT guide sets out when a second tracker beats moving modules.

This Is Not Australia: What Does Not Transfer

Worth stating plainly, because most tools sold into New Zealand were built for the market next door.

There is no Small-scale Technology Certificate scheme. No deeming period, no certificate price, no upfront discount line in the quote. A shading loss in Australia reduces system size and therefore reduces the certificate rebate, which is a second-order financial effect Australian tools model. That effect does not exist here, and a tool that carries the field will show an empty box.

There is no Clean Energy Council equivalent. No accreditation scheme gating a subsidy, no approved product list to filter against. An Australian-built platform’s CEC filter is dead weight in Auckland, and any compliance value has to come from the AS/NZS drawing set instead.

State feed-in tariff libraries are irrelevant. Export payment here is retailer-set and negotiable in practice, not set by a state scheme, so the tariff library that makes an Australian tool feel complete is the wrong shape.

The grid is already largely renewable. New Zealand generation runs roughly 80 to 90 percent renewable in most years, tracked by the Ministry of Business, Innovation and Employment and benchmarked internationally by the IEA. A shading report that leads with avoided carbon is arming your competitor. Lead with the money, which is exactly what the time-of-day valuation gives you.

For the neighbouring market and how little of it transfers, see our solar design software Australia ranking.

Should a New Zealand Team Standardise on SurgePV for Shading?

Verdict. For a five-person New Zealand installer, SurgePV is the strongest shading stack in New Zealand dollars because it is the only tool here that values a shading loss at the hour it occurs rather than at a blended annual rate, with the caveat that you maintain the retailer rates yourself. For a disputed commercial yield figure, keep PVsyst. For a battery-led shop, SolarPlus models the interaction more thoroughly. For a two-van outfit, OpenSolar free is genuinely correct.

How Heaven Green Energy and SurgePV Help New Zealand Teams

Heaven Green Energy has delivered more than 10,000 solar installations, and our engineering group builds the software we use ourselves. SurgePV came out of that: a design suite written by people who had to defend a savings figure to a customer six months after handover. For New Zealand teams the entry points are:

• Shadow analysis for 8,760-hour module-level shading with a monthly and time-of-day breakdown.
• Site survey and feasibility services when the obstruction geometry on a treed or sloped site has to be measured rather than inferred.
• A half-hourly data review before quoting, because the shading number is only as useful as the load profile you value it against.

For the wider New Zealand tool decision see our best solar design software in New Zealand ranking, the best solar proposal software in New Zealand guide and the full New Zealand software stack. References worth bookmarking: the Electricity Authority for distributed generation rules, the Energy Efficiency and Conservation Authority for programme data, and IRENA for deployment benchmarking. Choosing the best solar shading analysis software in New Zealand comes down to one question almost no global vendor asks: does the tool know what hour the shadow fell in, and what a kilowatt-hour was worth at that hour?

Related Shading and Design Guides

• Solar Shading Analysis Software: The Global Pillar
• Best Solar Shading Analysis Software UK
• Best Solar Shading Analysis Software in Ireland
• Best Solar Design Software in New Zealand
• Solar Design Software Australia: What Does Not Transfer
• Best Solar Design Software in Canada
• Solar Simulation Software Compared
• Commercial Solar Design Software Compared

Frequently Asked Questions

Is a solar shading study required in New Zealand?

No. No New Zealand regulation requires a photovoltaic shading study, and there is no shade factor equivalent to the British MCS Standard Estimation Method. Installation sits under the Electricity (Safety) Regulations 2010 with AS/NZS 5033 and AS/NZS 4777.2, and connection is governed by Part 6 of the Electricity Industry Participation Code through your local lines company. None of those asks for a shading report. The shading study is a commercial deliverable that protects your savings claim, not a compliance document.

Why does the time of day of a shading loss matter in New Zealand?

Because there is no national feed-in tariff, so a self-consumed kilowatt-hour is worth the full retail price avoided, commonly 28 to 34 cents, while an exported one is worth the retailer’s buyback, commonly 7 to 17 cents. On a 6 kW Auckland array with an eight percent shading loss, the same 680 kWh costs about NZ$82 a year if it falls entirely in midday export hours and about NZ$204 if it falls in morning and evening consumption hours. Only half-hourly modelling can tell the two apart.

Should New Zealand solar arrays face north or south?

North. New Zealand is in the southern hemisphere, so the sun tracks across the northern sky and shadows fall toward the south. Any tool defaulting a residential roof to south, or scoring a north-facing plane as poor, is running a northern-hemisphere convention and needs reconfiguring before you trust a single number it produces. Test it on a simple gable roof in the first five minutes of a trial.

When is the winter solstice for New Zealand shading calculations?

21 June. That is the day of the lowest sun angles and the longest shadows, and every minimum row pitch calculation should derive from it. A shading heat map that shows its deepest losses in December is describing a northern-hemisphere site. June is also when New Zealand heating load peaks, so the worst generation month and the highest consumption month coincide, which is why monthly reporting matters more here than the annual figure suggests.

How long is a winter shadow in Auckland compared with Invercargill?

At solar noon on 21 June the sun reaches about 29.7 degrees in Auckland at 36.8S, a shadow multiplier near 1.75, so a 3 metre chimney casts about 5.3 metres. Christchurch at 43.5S gets roughly 23.1 degrees and a multiplier near 2.35. Invercargill at 46.4S gets about 20.2 degrees and a multiplier near 2.72, so the same chimney casts 8.2 metres. A 20 degree flat-roof array needs about 3.5 metres of pitch in Auckland and 4.3 metres in Invercargill.

Can I get my customer’s half-hourly consumption data?

Yes, and you should ask for it before quoting. New Zealand retail metering is half-hourly, and most retailers will supply a customer’s consumption history on request, usually as a downloadable file covering twelve months. Joined to a half-hourly generation profile, that file turns the self-consumption fraction from an assumption into a calculation, and it is the only way to value a shading loss at what it actually costs rather than at a blended rate.

Is New Zealand shading analysis the same as Australian?

No, and treating it as Australia with worse weather is the expensive assumption. There is no Small-scale Technology Certificate scheme, so a shading-driven size change has no rebate consequence to model. There is no Clean Energy Council equivalent and no approved product list to filter against. Export is retailer-set rather than governed by state feed-in schemes. The diffuse fraction is higher and the southern latitudes produce a far sharper winter trough than most of Australia.

What is SurgePV’s biggest weakness for New Zealand shading work?

The lack of a maintained New Zealand retailer tariff library. The half-hourly valuation that makes it rank first is only as accurate as the buyback and import rates your team enters, and a retailer changing its export offer will not propagate to your quotes automatically. Its horizon capture is also satellite-derived rather than measured, which handles bush-clad sections poorly, its brand is thin against OpenSolar, and it is not a CRM so the Certificate of Compliance trail lives elsewhere.