Do You Need a North-Facing Roof for Solar?

No, you do not need a north-facing roof for solar to work in New Zealand. While due north is the textbook "optimal" orientation, modern panels are efficient enough that east-facing, west-facing, and even split east/west roofs produce excellent results, often within 10-20% of a north-facing system. In many cases, an east/west split is actually better for your household's economics, because it spreads generation across morning and evening when you're home using power. The myth that "north or nothing" still floats around Kiwi backyards, but the maths and the technology have moved on. If your roof faces anywhere from east through north to west, you're a strong candidate for solar.

This article is for the homeowner who's been told (often by a mate, sometimes by an installer) that their roof "isn't right" for solar. We'll walk through what orientation actually does to generation, why east/west splits can win on self-consumption, and what to watch for when an installer waves you off. We'll keep it grounded in NZ conditions, NIWA irradiance data, and how Kiwi homes actually use electricity.

What Roof Orientation Actually Means for NZ Homeowners

In the Southern Hemisphere, the sun tracks across the northern sky. So a roof tilted toward true north receives the most direct sunlight across the day, producing the highest total annual generation. That's where the "north-facing is best" rule comes from, and on a pure kWh-per-panel basis, it's still true.

But here's the catch most installers don't lead with: maximum generation isn't the same thing as maximum financial benefit. What you save depends on when you generate power, when you use it, and what your retailer pays for the surplus you export back to the grid.

NZ buy-back rates are almost always lower than the rate you pay to buy power from your retailer. So a unit of solar that you use yourself (offsetting a 28-35c/kWh purchase) is worth two to three times more than a unit you export (earning 7-17c/kWh, depending on your plan, as tracked in our hardware guide).

That single fact reshapes the whole orientation conversation. Suddenly, a roof that generates a bit less overall but generates it when you're home can be the better roof.

The compass directions in plain English

• North-facing: Peak generation around solar noon. Highest annual total.
• East-facing: Strong morning production from sunrise to about midday.
• West-facing: Strong afternoon and evening production until sunset.
• East/west split: Two arrays, one on each pitch. Spreads generation across the day with a small midday dip.
• South-facing: The genuinely tricky one. Significantly reduced output, especially on steeper pitches.

The Numbers: How Much Does Orientation Actually Cost You?

Let's get specific. Using standard PV modelling for NZ conditions (drawing on NIWA solar irradiance data and the modelling assumptions used by EECA in their residential solar guidance), here's roughly how different orientations compare to a north-facing benchmark at a typical 20-25 degree roof pitch:

• North-facing: 100% (the benchmark)
• Northeast or northwest: 95-98%
• East-facing: 85-90%
• West-facing: 85-90%
• East/west split (half and half): 85-90% combined
• Southeast or southwest: 75-85%
• South-facing: 60-75%, varies heavily with pitch

So an east-facing system produces around 10-15% less total energy than a north-facing one of the same size. That sounds like a lot until you remember the dollar value of each kWh is what matters. If your east-facing array generates power while you're making breakfast, packing lunches, and getting the kids out the door, every one of those kWh is offsetting a 30c retail rate rather than earning a 12c export rate.

A worked example (the kind your installer should show you)

Imagine two identical 6 kW systems on two identical houses next door to each other in Tauranga. One faces due north. The other faces due east. Annual generation roughly: 9,000 kWh (north) vs 7,800 kWh (east). On paper, the north system "wins" by 1,200 kWh.

But the east-facing household is up at 6am, runs the dishwasher and washing machine in the morning, and the homeowner works from home until lunch. Their self-consumption ratio is 65%. The north-facing house is empty from 8am to 5pm; their self-consumption ratio is 30%.

Run the maths through our Solar System Cost & ROI Calculator and the east-facing house can end up with a better annual return, because they're soaking up more of their own low-cost solar instead of selling it at low rates and buying back expensively. Orientation matters; lifestyle matters more.

Why East/West Splits Are Quietly the Best Option for Many NZ Homes

A huge proportion of NZ housing stock, particularly post-1970s subdivisions in Auckland, Hamilton, Christchurch, and the Hutt Valley, sits on gable-roofed homes with one face east and one face west. Until recently, installers would look at this and put all the panels on the slightly-better side (or refuse the job). Today, with cost-effective panels and smart string inverters or micro-inverters, splitting an array makes a lot of sense.

Here's why an east/west split is often the unsung hero of NZ residential solar:

• Generation curve matches Kiwi life. Morning peak (breakfast, getting ready) and evening peak (dinner, dishwasher, EV charging) are exactly when you're home using power.
• Higher self-consumption. Less surplus exported at low buy-back rates means more dollars saved.
• Smoother load on the inverter. A north-only array can hit a sharp midday peak that "clips" against the inverter's capacity. An east/west spread keeps the inverter working steadily across more hours, so a 5 kW inverter can comfortably handle a 6.5 kW panel array.
• Better synergy with batteries. Longer generation hours mean more chances to top up a battery before evening.
• Better fit with time-of-use plans. If you're on a dynamic tariff with Octopus Energy NZ or a TOU plan with Contact or Mercury, evening generation directly offsets your most expensive grid hours.

The trade-off: an east/west system on the same roof footprint produces slightly less total kWh than a north-facing one. But on most NZ homes, the financial outcome is comparable or better once self-consumption is factored in.

What This Means for You (By Persona)

For the ROI Pragmatist

Stop comparing systems by "kWh per kW installed". That's a vanity number. Ask your installer for two figures: estimated annual generation AND estimated self-consumption ratio. The second one is where your dollars actually live. A 6 kW east/west system with 60% self-consumption will usually out-earn a 6 kW north system with 30% self-consumption, full stop.

Run your specific numbers through the Solar System Cost & ROI Calculator before signing anything. Don't take an installer's payback estimate on faith; verify it.

For the Tech-Savvy Optimiser

An east/west split is your friend, especially paired with a battery and a dynamic tariff. You can charge the battery from morning surplus, hold it through the low-rate midday export window, and discharge against the 5-9pm peak. If your home has a Sungrow, Fronius, or Goodwe hybrid inverter, you can configure this behaviour directly. Pair it with a modern N-type panel for better low-light performance (which matters disproportionately on east/west pitches where sun strikes at sharper angles morning and evening).

For the Eco-Conscious Family

You probably care more about how much grid power you displace than about maximising kWh on a spreadsheet. East/west splits do exactly that: they push the most clean power into your home during the hours you actually use it, reducing your draw on the grid during peak demand (which in NZ still includes some thermal generation). Don't be talked out of solar because your roof "isn't north". It almost certainly works.

Common Pitfalls (What Some Installers Won't Tell You)

This is where being a savvy buyer pays off. Some installers, especially the big-volume ones, screen aggressively for north-facing roofs because it makes their quoting tools simpler and their headline kWh numbers look better. That doesn't mean your roof isn't viable. Watch for:

• "Sorry, your roof faces east, we can't help." This is rarely true in 2024-25. It usually means they've calibrated their business model around easy north-facing jobs. Get a second opinion.
• Quotes that ignore self-consumption. If the quote only shows annual kWh and a payback period, ask: "What self-consumption ratio did you assume?" If they can't answer, they've guessed.
• Underspeccing east/west systems. Some installers will quote a smaller system for a non-north roof "because it generates less". You may actually want a larger array on an east/west split to compensate, especially if you've got a heat pump or EV.
• Refusing to split arrays across pitches. If you've got a gable roof and they only want to put panels on one side "for tidiness", push back. A split costs slightly more in cabling but usually pays back fast.
• Ignoring inverter clipping headroom. Ask whether your inverter can be safely oversized relative to the panel array, given that the east/west split flattens the production curve. The answer should be "yes, and here's by how much".

If you're feeling unsure, get multiple quotes from vetted installers and compare not just price but how they handle these questions. That's exactly what our free quotes service is built for.

South-Facing Roofs: The Genuinely Hard Case

Let's be honest. If your only available roof is genuinely south-facing with a steep pitch (say, 35+ degrees), solar gets harder. You'll likely generate 60-70% of what a north-facing array would produce on the same house, and winter performance will be noticeably weaker.

That said, "harder" doesn't mean "don't bother". A few things to consider:

• Low-pitch south roofs (10 degrees or less) are surprisingly close to flat, and a flat roof is only about 10-15% worse than north-tilted. These work.
• Tilt frames can mount panels at a north-facing angle on a south-facing roof. They cost more and look more industrial, but on a tin roof they're a legitimate option.
• Carports, garages, sheds may face better directions than your house. Don't forget the outbuildings.
• Ground-mount systems on rural and lifestyle blocks bypass the roof orientation problem entirely. If you've got the land, it's worth pricing.

If you genuinely can't find north, east, or west exposure anywhere on your property, then solar may not be the right fit right now. But that's a small minority of NZ homes.

Roof Pitch: The Underrated Sibling of Orientation

Most conversations about "is my roof good for solar" focus on which way it faces, but the angle of the pitch matters too. For most NZ latitudes (roughly 35-46° south), the ideal panel tilt is around 25-35 degrees, which happens to match common NZ roof pitches reasonably well.

A few quick rules of thumb:

• 10-30 degree pitch: The sweet spot. Forgives orientation errors well.
• 30-45 degree pitch: Closer to "winter optimal", great for winter generation but slightly less annually.
• 0-10 degree pitch (near flat): Solid generation in summer, weaker in winter; watch for water pooling and dirt accumulation. Panels may need more frequent cleaning.
• 45+ degree pitch: Less common in NZ; reduces annual output, especially on east/west or south.

This matters more in Otago, Southland, and the lower South Island, where lower winter sun makes pitch a genuine factor. Northland and Auckland are more forgiving.

Frequently Asked Questions

Do I really not need a north-facing roof for solar in NZ?

Correct. North is optimal in pure generation terms, but east, west, northeast, northwest, and east/west split roofs all work very well in NZ conditions. You'll typically lose 5-15% of total generation compared to a north-facing roof of the same size, but you may gain back much of that (or more) in higher self-consumption.

What's the worst-case orientation?

A steep south-facing roof. Annual output drops to roughly 60-70% of a north-facing benchmark, and winter performance is weak. You still can install solar on such a roof, but the payback period stretches and you should explore tilt frames or alternative roof faces first.

Is an east/west split worth it?

Often yes, especially for households that use most of their power in mornings and evenings (which is most NZ households). The flatter generation curve means higher self-consumption, less wasted export at low buy-back rates, and a smoother match with batteries and time-of-use tariffs.

Will my installer charge more for a non-north installation?

Sometimes slightly more, because splitting an array across two roof faces involves more cabling and sometimes two strings on the inverter. The extra cost is usually small (a few hundred dollars) and pays back quickly through better self-consumption.

Does roof pitch matter as much as orientation?

It matters less than orientation in most cases, but it isn't trivial. NZ's standard 20-30 degree pitch is close to ideal for year-round generation. Very flat or very steep roofs can lose a few percent of annual output.

Can I add panels in stages if my best roof faces aren't all north?

Technically yes, but it's almost always more cost-effective to install the full system in one go. Adding panels later means a second site visit, possibly a new inverter, and extra scaffolding fees. If you can afford to do it all at once, do.

What if my roof is partly shaded by trees or neighbours?

Shading hurts more than orientation. A north-facing roof with afternoon shade from a neighbouring two-storey home can underperform an unshaded east-facing roof. Ask your installer to model shading specifically. Micro-inverters or DC optimisers (Enphase, SolarEdge, Tigo) can mitigate partial shading effects on individual panels.

How do I find out my roof's true orientation?

Use Google Maps or LINZ's online aerial imagery. Open the map, find your house, and the road grid plus compass direction will tell you which way your ridge runs. North in NZ is "up" on Google Maps by default. Your installer will confirm with a site visit and shade modelling.

Should I worry about magnetic vs true north?

There's about a 20-25 degree difference between magnetic and true north in NZ (it varies by region). Solar performance is calculated against true north. Don't try to do this with a phone compass; let the installer's professional tools handle it.

Does panel technology matter on a non-north roof?

It can. Modern N-type panels (TOPCon, HJT) have slightly better low-light and high-angle performance than older P-type modules, which can help on east/west pitches that receive sun at sharper angles morning and evening. See our piece on N-type vs P-type cells for the detail, and our review of DAS Solar and Tongwei N-type panels for specific options. Tier-1 manufacturer status also matters for warranty reasons; see our explainer on what Tier-1 actually means.

Where to Go From Here

The "north-facing or nothing" myth has held back more Kiwi solar installations than just about any other piece of folk wisdom. The truth is that most NZ homes have a perfectly viable solar roof, and many homes with east/west pitches will actually do better financially than they would on north-only generation.

The right next step is to get specific. Have a look at your roof on Google Maps, take note of which directions your major roof faces point, and ask multiple installers how they'd configure a system. Run the numbers honestly through the Solar System Cost & ROI Calculator, and read more on hardware choices in our complete guide to NZ solar hardware and tech. If an installer tries to wave you off because your roof "isn't right", get a second opinion before you accept that as the final word.