Key points
- North is best, but not by as much as most people think. East- or west-facing panels produce about 82–87% of a north-facing system in Adelaide and Melbourne.
- North-east and north-west roofs lose only about 3–7%. South-facing panels on a typical 22° roof produce about two-thirds of north.
- East-west systems lose most of their output in winter. In summer they produce about the same as north-facing panels.
- Shade usually costs more than orientation. Panel-level electronics (microinverters or optimisers) can recover much of the loss.
Solar panel roof orientation matters, but less than you might expect. In Adelaide and Melbourne, north-facing panels produce the most energy over a year. East- and west-facing panels produce roughly 82–87% as much, north-east and north-west 93–97%, and south-facing panels on a standard roof around 66–68%. Shade from trees, chimneys or neighbouring buildings often costs more than a less-than-ideal direction. This guide gives modelled figures for both cities and explains how to handle tricky roofs.
Solar panel roof orientation: which way should panels face?
In the southern hemisphere the sun sits in the northern half of the sky, so north-facing panels see the most sunlight across the year. That’s the starting point, not a rule. Many homes in Adelaide and Melbourne put panels on east and west roofs, and they work well.
To show the real difference, we modelled a 1 kW system at a typical 22° roof pitch using the European Commission’s PVGIS tool, which uses satellite weather data and assumes 14% system losses. The results are annual generation per kilowatt of panels.
| Panel direction | Adelaide (kWh/kW/yr) | Adelaide vs north | Melbourne (kWh/kW/yr) | Melbourne vs north |
|---|---|---|---|---|
| North | 1,578 | 100% | 1,399 | 100% |
| North-east | 1,518 | 96% | 1,362 | 97% |
| North-west | 1,518 | 96% | 1,308 | 93% |
| East | 1,356 | 86% | 1,214 | 87% |
| West | 1,359 | 86% | 1,145 | 82% |
| South-east | 1,161 | 74% | 1,029 | 74% |
| South-west | 1,165 | 74% | 983 | 70% |
| South | 1,065 | 68% | 925 | 66% |
A north-facing system in Adelaide averages about 4.3 kWh per kW per day; in Melbourne about 3.8 kWh. In the Melbourne model, west-facing panels came out a little behind east-facing ones, which likely reflects afternoon weather in the satellite data. Treat small differences like that as within the margin of error. These figures line up with other industry estimates: SolarQuotes, for example, puts the loss for east or west panels at about 12% and for north-east or north-west at about 5%.
This guide is part of our complete guide to buying home solar panels. For what a typical system produces month by month, see how much power a 6.6kW system produces.
Are east-west solar panels worth it?
Usually, yes. East-west systems trade some total output for a wider daily production curve. East panels start producing earlier in the morning and west panels keep going later into the afternoon, when many households are home and using power.
The seasonal pattern matters too. In the PVGIS model for Adelaide, a north-facing kilowatt produces about 170 kWh in December and an east-facing kilowatt about the same. In June the north-facing kilowatt produces about 81 kWh but the east-facing one only about 52 kWh. East-west roofs lose most of their output in winter, when the low sun favours north.
Worked example: 6.6 kW in Adelaide
- All panels north-facing: 6.6 × 1,578 = about 10,400 kWh a year.
- Half east, half west: 6.6 × 1,358 (average of east and west) = about 8,960 kWh a year, or 14% less.
- To match the north-facing output on an east-west roof, you would need about 7.7 kW of panels, roughly two or three extra panels.
With feed-in tariffs now low in both states, extra panels on an east-west roof are often a cheap way to close the gap, provided your inverter and export limit allow it. Our guide on what size solar system you need explains how to size for your usage.
Is it worth putting solar panels on a south-facing roof?
Sometimes. On a 22° roof, south-facing panels produce about 66–68% of north in Adelaide and Melbourne. Roof pitch makes a big difference:
| Roof pitch | Adelaide north | Adelaide east | Adelaide south | Melbourne north | Melbourne east | Melbourne south |
|---|---|---|---|---|---|---|
| 10° (low pitch) | 1,504 | 1,392 | 1,266 | 1,329 | 1,241 | 1,107 |
| 22° (typical) | 1,578 | 1,356 | 1,065 | 1,399 | 1,214 | 925 |
| 35° (steep) | 1,597 | 1,293 | 850 | 1,421 | 1,164 | 738 |
Figures are kWh per kW per year from the same PVGIS model. On a low-pitched 10° roof, south-facing panels still produce about 83–84% of north. On a steep 35° roof, they drop to just over half. If you only have a south roof, a low pitch or tilt frames that angle the panels towards north can help, but tilting panels “backwards” on a south roof needs careful engineering for wind loads.
The table also shows that roof pitch barely matters for north-facing panels. A typical 22° pitch produces within about 1–2% of a steep 35° pitch, so tilt frames on a north roof are rarely worth the cost.
How much does shade reduce solar output?
Shade can cost more than any orientation choice. In a standard string system, panels are wired in series, so shade on one panel can pull down the output of every panel in that string. Modern panels reduce the damage with bypass diodes (usually three per panel) and half-cut cell designs, but they don’t eliminate it.
The most important hours are roughly 9am to 3pm, when panels produce most of their energy. Common shade sources include:
- Trees, including a neighbour’s tree that will keep growing
- Chimneys, flues, vents and TV antennas
- Neighbouring two-storey homes, especially in newer estates
- Your own roof, where one roof section shades another
Winter shadows are much longer
At noon on the winter solstice the sun is only about 32° above the horizon in Adelaide and about 29° in Melbourne. A 2-metre-high obstruction then casts a shadow of about 3.2 metres in Adelaide and 3.6 metres in Melbourne, even at midday. In summer, when the sun is around 76–79° high at noon, the same obstruction casts almost no shadow. That’s why a site inspection in summer can miss a winter shading problem. A good installer models shade for the whole year.
How to get the most from a difficult roof
- Use the best roof faces first. Put as many panels as possible on north, north-east or north-west, then use east and west.
- Keep each orientation on its own MPPT. Most modern string inverters have two maximum power point trackers, so east and west strings can run independently.
- Consider panel-level electronics for shade. Microinverters or optimisers let each panel work independently. See our guide to solar inverter types.
- Avoid shaded spots altogether. Sometimes leaving a shaded section empty produces more than filling it.
- Shift your usage. East-west systems suit households that run appliances in the morning and late afternoon. Read our tips to use more of your own solar power.
Tip: Ask every installer for a site-specific design and an annual kWh estimate that accounts for your roof directions and shading. Under the New Energy Tech Consumer Code, Approved Sellers must provide both for a custom installation.
Local conditions differ between the two cities, from Adelaide’s hot, clear summers to Melbourne’s cloudier winters. Our location guides for solar panels in Adelaide and solar panels in Melbourne cover what to expect in each.
Frequently asked questions
Do solar panels have to face north?
No. North-facing panels produce the most over a year, but east- and west-facing panels in Adelaide and Melbourne still produce roughly 82–87% as much, and north-east or north-west about 93–97%. Many systems combine east and west roofs, adding one or two extra panels to make up the difference.
Is east or west better for solar panels?
In modelled annual output the difference is small. West-facing panels produce more in the late afternoon, which can suit households that use power after work, while east-facing panels help with morning loads. Choose based on which roof is less shaded and when your household uses the most electricity.
Can I put solar panels on a south-facing roof?
You can, but expect about 66–68% of north-facing output on a typical 22° roof in Adelaide or Melbourne. On a low-pitched roof of around 10°, south panels produce about 83–84% of north. South panels make most sense when other roof faces are full or shaded.
Will a little shade ruin my solar system?
Not usually, but it can cost more than you expect, because shade on one panel can reduce a whole string’s output. Avoid shade between about 9am and 3pm where possible. If shade can’t be avoided, microinverters or optimisers let each panel work independently and recover much of the loss.
Every roof is different. Our installers in Adelaide and Melbourne design each system around your roof directions, pitch and shading, and our 6.6kW solar system package can be laid out across north, east or west roofs. Get a free quote with a site-specific output estimate.
Sources: European Commission Joint Research Centre – PVGIS 5.2 photovoltaic performance tool (modelled October 2026, ERA5 weather data 2005–2020, 22° tilt unless stated, 14% system losses); SolarQuotes – How your roof affects your solar (2026); New Energy Tech Consumer Code. Modelled figures are estimates; actual output depends on your exact roof, shading, equipment and weather. Featured image: Benlisquare / Wikimedia Commons, CC BY-SA 4.0.
