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System Design

Read the roof before the compass

Direction, roof shape, shade and load timing belong in the same decision.

Read the roof before the compassA plan-view roof sits below a north arrow, with an obstruction beside it and a separate load-data card. The drawing groups the information needed for orientation decisions; it is not a sun-path or yield model.N1WE23Interval load + objective4
Conceptual site plan — no optimum tilt, sun path or yield ratio is implied.
Explore the numbered points

POINT 1

North is a starting point

In Australia, north is a general annual-exposure starting point. East and west shift the production profile towards morning and afternoon.

POINT 2

Work with the actual faces

Record roof pitch, usable area and access before comparing layouts. Different roof groups also need suitable string and MPPT allocation.

POINT 3

Include what blocks the light

Observe recurring shade and horizon obstructions. Record seasonal uncertainty rather than assuming one visit covers the year.

POINT 4

Match the stated objective

Compare production timing with measured consumption, tariffs, export controls and battery operation. More energy is not automatically more bill value.

Use it in the field

FROM THE DIAGRAM TO THE JOB

Keep these checks with you.

  1. Agree the objective

    State whether the design targets energy, self-use, timing or a physical constraint.

  2. Compare like-for-like layouts

    Keep weather, equipment and loss assumptions consistent.

  3. Record the decision

    Save orientation, tilt, shade and load assumptions with the estimate.

Choose a modelled site outcome, not a universal compass rule.

Read the guide's sources
Sources listedReviewed August 2026Our methodology
Article details and scope
Topic
Array layout
Region
Southern hemisphere
Reading time
~4 min
Neutrality
Manufacturer-neutral
Read the full explainer
Key takeaways
  • In Australia, a north-facing array is a general starting point for annual solar access; site-specific shade, tilt, horizon and weather can change the result.
  • East- or west-facing modules shift generation earlier or later. Whether that improves bill value depends on measured load timing, import and export tariffs, export controls and storage operation.
  • Model the usable roof options before moving modules or adding tilt frames. Record assumptions so the customer can see whether the design targets yield, self-use, a constrained export window or a seasonal load.

Choose the objective first

An orientation cannot be “best” until the design objective is stated. Common objectives include annual energy, self-consumption, production during a constrained export window, seasonal output, usable system size or lowest installed complexity.

What direction changes

  • North: the Australian Government's YourHome guide gives north as a general southern-hemisphere rule for annual solar exposure.
  • East or north-east: moves more of the production profile towards morning.
  • West or north-west: moves more of the profile towards afternoon.
  • Split arrays: can broaden the production window, subject to shade and suitable string or MPPT allocation.

These are profile descriptions, not financial conclusions. Local irradiance, horizon, shade and roof pitch determine the energy. Interval consumption, tariffs, export controls and battery operation determine its value.

Field workflow

  1. Mark every usable roof face, pitch and obstruction.
  2. Record recurring shade across the day and note seasonal uncertainty.
  3. Confirm the customer's objective and obtain interval load data where available.
  4. Model realistic layouts with the same weather, losses and equipment assumptions.
  5. Check that differently performing groups are allocated to suitable strings and MPPT inputs.
  6. Record export limits, tariff assumptions and battery controls separately from the yield model.

Tilt is not only an energy calculation

Tilt changes solar access and seasonal production, but the installed decision also includes the existing roof, mounting certification, wind actions, row spacing, drainage, debris and safe access. Do not recommend a tilt frame from a latitude rule alone. Compare the modelled gain with the added design, installation and maintenance consequences.

What to hand over

Keep the proposed orientation, tilt, shade assumptions, annual estimate and production profile together. State whether the layout was chosen for annual yield, time-of-day fit or a physical constraint. The estimate is a design aid, not a production guarantee.

New to the jargon? Browse the glossary.

Sources

Best next action

Near-Shade Sun-Path CheckDo this next

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Frequently asked

Is north always the best orientation in Australia?
No. North is a general starting point for annual exposure in the southern hemisphere, but shade, roof pitch, horizon, local weather and usable area can make another layout perform better for a particular site or objective.
Will east/west panels save more money?
Not automatically. They can shift production into morning and afternoon periods, but bill value depends on the site's interval consumption, import and export tariffs, export limits and any battery controls. Compare modelled options using the same assumptions.
Should tilt equal the site's latitude?
Latitude is a broad annual-yield starting point, not a universal prescription. Existing roof pitch, wind and mounting requirements, soiling, seasonal loads, shading and installation cost all belong in the decision.
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