Orientation Matters More in Perth Than Most Places
Perth has high solar irradiance, a 5kW export cap, and near-zero off-peak export rates. Together, this means where you point your panels has a real impact on how much value you get from your system. It is not just about total generation. It is about when that generation happens, and whether it lines up with your consumption and battery charging needs.
The standard advice is ‘face them north,’ and north is a strong default. But Positive Energy Solutions designs every system with a battery, and for these Perth households, east and west orientations offer advantages that are often overlooked. For most suburban roofs, a multi-aspect approach captures the best of all directions.
This guide covers what each orientation actually delivers in Perth. It also covers how orientation and battery strategy work together, and how Positive Energy Solutions’ engineering team approaches roofs with multiple usable aspects.
North-Facing: The Benchmark
North-facing panels are the standard recommendation for solar in the Southern Hemisphere. They receive the most direct sunlight across the full day. The sun tracks across the northern sky from east to west. North-facing panels are exposed to it throughout the generation window.
In Perth, a north-facing array at the right pitch produces more energy across the year than any other single direction. It is the reference point that east and west are compared against.
What north-facing delivers:
- Strong, sustained generation from around 8am through to 4pm
- Peak output around solar noon (12pm to 1pm)
- The highest total daily kWh output in both summer and winter
- Consistent battery charging. The battery reaches full charge by early to mid afternoon on most clear days
Best suited for:
- Households focused on getting the most total generation
- Daytime-heavy usage profiles, such as a home office, pool, or ducted AC running during the day
- Systems where DEBS export during the midday window is part of the savings strategy
If your roof has a clear, unshaded north-facing section of a reasonable size and pitch, this is usually where the main array goes. Everything else builds from here.
East-Facing: The Morning Advantage and Early Battery Charge
East-facing panels catch the morning sun earlier and more directly than north-facing panels. They generate meaningful output from around 7am to 8am onwards. That is a full hour or more before a north-facing array reaches similar output levels.
In terms of total daily generation, east-facing panels produce around 85% to 90% of what a comparable north-facing array would generate. The trade-off is that east-facing output drops away faster in the afternoon, as the sun moves away from the east side of the sky.
The battery advantage of east-facing panels:
For households with a battery, east-facing panels have a specific benefit that goes beyond total generation. They charge the battery earlier. A system with east-facing panels starts filling the battery from 7am to 8am. A purely north-facing array does not make meaningful surplus until 9am to 10am. The battery reaches full charge earlier in the day. That means it has more capacity ready for evening use, and more day left to build up surplus.
Best suited for:
- Households with morning-heavy loads, such as hot water, dishwasher, or early breakfast routines
- Battery systems where early charge is a priority
- Roofs where north-facing space is limited but east-facing space is available
- As a complement to north or west panels in a multi-aspect array
West-Facing: The Evening Advantage and Battery Conservation
West-facing panels do the opposite job to east-facing panels. They generate less in the morning and reach peak output in the early afternoon. They keep producing meaningfully until 5pm to 6pm, well after north-facing panels have tapered off.
Like east-facing, west-facing panels produce around 85% to 90% of a comparable north-facing array in total daily generation. But the timing of that generation is what makes them especially valuable for battery households in Perth.
The battery conservation advantage of west-facing panels:
West-facing panels stretch out the period during which solar generation can cover your home’s load directly. They keep producing through the late afternoon and into early evening. This means the battery does not need to start discharging as early. More battery capacity is saved for the later evening hours when there is no solar generation at all. The result is better overnight coverage and less grid draw before the panels start generating again the next morning.
This is probably the most overlooked benefit of west-facing panels in Perth. The question is not just how much a panel generates, but when it generates. West-facing panels generate at exactly the time that delays battery draw-down and boosts overnight coverage.
The DEBS advantage of west-facing panels:
West-facing panels also have a financial advantage, for systems eligible for DEBS export payments (an inverter of 5kW or under). They generate through the 3pm to 9pm peak export window, when exported electricity earns 10 cents per kWh rather than 2 cents. Any generation not used directly or stored in the battery during this window is exported at the higher rate.
Best suited for:
- Battery households wanting to maximise overnight coverage
- Households with evening-heavy loads, such as cooking, TV, or AC running into the evening
- DEBS-eligible systems where afternoon export revenue is part of the savings strategy
- As a complement to north or east panels in a multi-aspect array
Multi-Aspect Arrays: Capturing the Best of All Directions
Most suburban Perth roofs have usable space on more than one aspect. A multi-aspect array means panels on two or more roof faces. This is often the most effective design for a battery household. It spreads generation across a longer window, rather than concentrating it in a single midday peak.
The right combination depends on your specific roof layout, usable area on each aspect, shading, and consumption profile. Positive Energy Solutions’ engineering team models each aspect during the design review. The goal is the configuration that delivers the best outcome for your household — not just the highest total kWh on paper.
What About South-Facing Panels?
South-facing panels receive the least direct sunlight in Perth. They generate significantly less than any other orientation — typically 60% to 70% of a comparable north-facing array. They are generally avoided as a primary or sole orientation.
That said, south-facing panels are sometimes included in a large multi-aspect array. This works where the roof has good south-facing space, and where the household’s usage is high enough to benefit from every extra kilowatt-hour. In these cases, the small amount of generation from south-facing panels still helps with battery charging and self-consumption. It is just lower value per panel than any other direction.
If your roof is predominantly south-facing, this is an important conversation to have with your Positive Energy Solutions consultant before system design begins. It significantly affects what output you can realistically expect.
Roof Pitch: The 25-Degree Optimum and Steep Roof Considerations
Roof pitch — the angle of the roof surface from horizontal — affects how directly panels face the sun at different times of year. In Perth, a pitch of 25 degrees is the optimum for annual generation. This angle balances summer and winter sun angles to get the most total output across the year.
Most suburban Perth homes fall between 15 and 25 degrees. This puts them close to the optimum without any adjustment needed. Panels are typically mounted flush to the roof surface rather than on angled frames.
Flat roofs:
Flat commercial roofs and some residential flat-roof areas can use tilt frames to reach the optimal 25-degree angle. But for residential properties with enough roof space, fitting more panels at a low angle is usually cheaper than installing tilt frames for fewer panels. Tilt frames add material and labour cost. On flat roofs they also need more spacing between rows, to stop rows shading each other, which reduces the number of panels that can fit in a given area. Where space allows, more panels at low pitch typically beats fewer tilted panels on a cost-per-kilowatt-hour basis.
Steep roofs (over 30 degrees):
Roof pitches above 30 degrees carry a real safety risk for installation crews. Most installers will not work on roofs steeper than this without special equipment and procedures. Some period homes and certain architectural styles have a steep pitch. If your home has one, this needs to be spotted early in the design process. Your Positive Energy Solutions consultant will flag this when reviewing your switchboard photos and satellite imagery. The engineering team will check feasibility before any work is scheduled.
If you are unsure of your roof pitch, send a photo of your roofline to your Positive Energy Solutions consultant. It can usually be estimated from images and confirmed during the site assessment on installation day.
How Shading Changes the Equation
Shading is often the factor that overrides orientation preferences. A north-facing roof section can have significant shading from a neighbouring building, trees, or rooftop obstructions. This section can underperform a partially shaded west-facing section with better direct sun access for more of the day.
Shading effects reach beyond the shaded panels themselves. On a standard string inverter, shading on one panel reduces the output of the entire string it belongs to. Some roofs have shading on part of the array that cannot be avoided. For these, panel-level optimisation or a suitable inverter set-up can reduce the impact. This is something the Positive Energy Solutions engineering team checks during the design review.
In practice, this means the best orientation for your system is the one that gets the most unshaded generation for your specific roof. This may not always be the theoretical best direction.
How Positive Energy Solutions Designs for Your Specific Roof
No two roofs are the same. Aspect, pitch, shading, usable area, structural features, and household usage all play a part. Together, they mean the best system design for your home cannot be worked out from a postcode alone.
Every Positive Energy Solutions system goes through a multi-stage engineering review. This review models generation performance for each available roof aspect, accounts for shading and clearance rules, and lands on a set-up that gets the best real-world output for your specific site. The installer then does a final check on installation day to confirm the design works, and has the authority to make adjustments if site conditions require it.
The result is a system designed around your roof and your usage, not a template applied to your address.
Talk to Positive Energy Solutions About Your Roof
If you are not sure which direction your roof faces, or how your orientation affects your options, the best starting point is a conversation with a Positive Energy Solutions consultant. Send through a photo of your home from street level and photos of your switchboard. The team can assess your roof layout, identify the best aspects for panel placement, and put together a design that makes the most of what your property offers.
Visit the Positive Energy Solutions showroom in Osborne Park or request a quote online.
Related guides
- Solar Panel Cleaning Perth 2026: How Often, What Damages Output, and How PES Monitors Your System
- Before Your Solar Is Installed in Perth: What to Expect From Sign-Off to Installation Day
- How Much Solar Battery Storage Do I Need? Perth 2026 Guide
- How to Choose a Solar Installer in Perth: What to Look For (and What to Watch Out For)
Frequently Asked Questions
Does panel orientation affect my DEBS eligibility?
No. DEBS eligibility is determined by inverter size (5kW or under), not panel orientation. However, orientation does affect how much you export and when. West-facing panels generate through the 3pm to 9pm peak export window. DEBS-eligible systems with west-facing panels tend to earn more in export credits than purely north-facing systems of the same size.
My roof mostly faces east-west with no usable north face. Is solar still worth it?
Yes. An east-west split array, with panels on both the east and west faces of a gable roof, is a well-established, effective set-up. It spreads generation across a longer daily window than a single north-facing array. It also pairs well with a battery, which charges gradually throughout the day from both sides. Total daily generation is slightly lower than a comparable north-facing array. However, the longer generation window and battery fit often make it the better practical outcome for households with this roof layout.
Will west-facing panels really make a meaningful difference to my battery overnight coverage?
Yes, measurably. West-facing panels generate through the late afternoon and into early evening. This means they cover your home’s load during the 3pm to 6pm period directly, rather than drawing from the battery. That is typically 2 to 4 kWh of load covered by panels that would otherwise come from the battery. This translates directly to more battery capacity available for the later evening hours and overnight. For households with higher evening loads, this can be the difference between the battery lasting through the night and needing a grid top-up before morning.
Can I add panels to a different roof face later if I want more generation?
Yes, with planning. Adding panels to a new roof aspect after the initial installation needs a Western Power application update. It may also involve extra string or inverter set-up, depending on how the existing system works. It is generally more straightforward on a hybrid inverter system. If there is any chance you will want to expand to a second aspect in future, mention this at the design stage, so the initial system can be set up to allow for it.
How do I find out which direction my roof faces?
The easiest way is to check Google Maps satellite view with compass orientation enabled. Your roof’s aspect will be visible. You can also use a compass app on your phone from the roof or from the ground looking up. When you send through a photo of your home to your Positive Energy Solutions consultant, the team can identify the main roof aspects from the image and factor them into the design.
Does roof pitch matter as much as orientation?
Pitch matters, but less than orientation for most suburban Perth homes. A roof between 15 and 30 degrees in any of the main orientations will perform reasonably well. The biggest pitch-related issue is at the extremes. Very flat roofs (under 5 degrees) can accumulate dust and bird droppings that reduce output. Steep roofs (over 30 degrees) present safety constraints that affect whether installation is feasible at all.
About the Author
Jason Wiktorowicz
Sales Manager, Positive Energy Solutions | Perth, WA
Jason has been at the centre of Western Australia’s energy transition for over a decade. As Orchestration Lead on Project Symphony — WA’s largest virtual power plant pilot — and Stream Lead on Project Encore, he worked directly with AEMO, Western Power and Energy Policy WA to shape how distributed energy resources connect and operate on the SWIS. That work included developing and rolling out CSIP-AUS, now mandatory for all new WA grid connections. He also led Emergency Solar Management (ESM), the first program of its kind in WA, VPP for Schools (VPP4S), which provided direct market benefits through Supplementary Reserve Capacity, and REBAR, the WA Residential Battery Rebate scheme.
His earlier career spanned Synergy, Infinite Energy and Curtin University’s Sustainability Policy Institute, where he co-authored peer-reviewed research on net-zero urban precincts, solar integration and peer-to-peer energy trading, published in the journal Urban Planning in 2018.
At Positive Energy Solutions, Jason leads sales with a focus on system design accuracy and long-term performance. Positive Energy Solutions installs solar and battery systems, EV chargers and heat pumps, and holds partner accreditations with Fronius, SigEnergy, iStore and SunPower. Connect with him on LinkedIn.
