SOLAR ORIENTATION: PERTH
Which way should solar panels face in Perth?
North. In Perth a north facing system at 15° makes about 1,670 kWh per kW a year, so a typical 6.6 kW system makes around 11,020 kWh. East facing panels make about 90% of that, west facing about 90% and south facing about 80%. The tool below is already set to Perth; drag the pin to your own roof or change the layouts.
| Panels facing (15° tilt) | Per kW, per year | 6.6 kW system | vs north | Summer / winter per kW |
|---|---|---|---|---|
| North | 1,669 kWh | 11,017 kWh | 100% | 546 / 278 kWh |
| East | 1,508 kWh | 9,950 kWh | 90% | 539 / 214 kWh |
| West | 1,507 kWh | 9,945 kWh | 90% | 542 / 212 kWh |
| South | 1,328 kWh | 8,768 kWh | 80% | 532 / 144 kWh |
Modelled AC output from a typical weather year for central Perth (2005–2023 PVGIS data), 14% system losses plus inverter losses, no shading.
Is east or west better in Perth?
In Perth it barely matters. East and west facing panels at 15° make almost exactly the same energy over a year, about 90% of a north facing roof. The real difference is timing.
On a clear summer day in Perth, north facing panels peak around 12:30, east facing panels around 11:20 and west facing panels around 13:30 (local standard time, so add an hour during daylight saving where it applies). If you use most of your power in the afternoon, or you want a battery full before the evening peak, west facing panels line up with that better than the annual numbers suggest.
Are south facing panels worth it in Perth?
Usually, yes. South facing panels at 15° make about 1,330 kWh per kW a year in Perth, which is 80% of the same panels facing north. At the Solar Choice price index figure of $0.88 to $0.95 per watt installed, that energy works out to roughly 2.8c to 3.0c per kWh over 25 years. That is around what retailers typically pay for exported solar, and a small fraction of what grid power costs, so extra panels on the south side generally pay their way.
The catch is winter. From December to February south facing panels make about 97% of what north facing ones do, but from June to August that drops to about 52%. They suit homes that use the most power in the warmer months, or have a battery to fill.
Flatter is better on a south facing roof. At 5° a south facing layout in Perth makes about 88% of a north facing system at 15°. Check that your inverter has room for the extra panels and how much your network lets you export before you commit.
What is the best tilt for solar panels in Perth?
Facing north, the tilt that makes the most energy over a year in Perth is about 29°, but it only adds about 3% over a 15° roof. A common 22.5° pitch gets 99% of the best possible. In other words, use the roof pitch you have. Tilt frames on a pitched roof almost never pay for themselves. The Solar Panel Angle Calculator shows the full picture for any direction and tilt.
How much does solar output change through the year in Perth?
A lot. North facing panels in Perth make about 546 kWh per kW over summer and about 278 kWh over winter, so winter output is roughly 51% of summer. Steeper panels flatten that out a bit, which is worth trying in the tool if your winter bills are the big ones.
Where do these numbers come from?
They are modelled with the same engine as the Solar Panel Orientation Comparison, using a typical meteorological year from PVGIS, the solar database run by the European Commission Joint Research Centre. Each hour of the year is worked through for every panel direction, then reduced for panel heat, 14% system losses and a 96% efficient inverter. Your own roof will differ with shading, panel brand and exact location, so treat these as a guide rather than a quote.
Other cities
See the same comparison for Sydney, Melbourne, Brisbane, Adelaide, Canberra, Hobart and Darwin, or read which way solar panels should face in Australia for the national picture. Outside Australia, there are city by city results for the UK and the US.
Common questions
Which direction is best for solar panels in Perth?
North. A north facing system at 15 degrees makes about 1,670 kWh per kW a year in Perth. East facing panels make about 90% of that, west facing about 90% and south facing about 80%.
Are east west solar panels worth it in Perth?
Often, yes. In Perth east and west facing panels both make about 90% of a north facing roof, and they spread output across the morning and afternoon, which suits homes that use power outside the middle of the day.
Is it worth putting solar panels on a south facing roof in Perth?
Usually. South facing panels make about 80% of north facing ones in Perth, and at current installed prices of $0.88 to $0.95 per watt that works out to roughly 2.8c to 3.0c per kWh over 25 years. Output drops to about 52% of north in winter, so they suit summer loads or a battery.
Need monitoring for your solar system?
These numbers show what a roof in Perth should make. PV Fleet checks whether yours actually does. It connects to the inverter monitoring you already have, learns what your system should produce and alerts you within hours when something goes wrong.