North vs east-west solar: which roof orientation is best for Adelaide?

The textbook answer

North-facing solar at a 35-degree tilt is the optimal orientation for Adelaide (latitude -34.93). It captures the most kilowatt-hours per year - approximately 4.4 peak sun hours per day on annual average.

What the textbook misses

With retailer feed-in tariffs at 2-8c per kWh and grid peak prices at 42-45c per kWh, the value of solar lies in self-consumption, not raw generation. If your household uses most of its power in the morning and afternoon (typical pattern: kettle and shower 7am, aircon ramp-up 5pm), an east-west split system may save you more money than a north-only system that generates more peak midday power than you can consume.

Adelaide annual production by orientation

Approximate annual output for a 6.6 kW Adelaide system at the typical 22.5-degree roof pitch:

• North: 10,200 kWh/year (baseline 100%)
• North-east or north-west: 9,900 kWh/year (97%)
• East: 8,900 kWh/year (87%)
• West: 8,900 kWh/year (87%)
• East + west split (half each): 8,900 kWh/year (87%) but spread morning + afternoon
• South: 7,200 kWh/year (71%) - rarely worth it

Self-consumption maths comparison

For a typical Adelaide home using 22 kWh/day:

North-only 6.6 kW:

• Daily generation: 28 kWh
• Self-consumed: 11 kWh (40%)
• Exported: 17 kWh @ 6c = $1.02
• Daily savings: 11 kWh @ 42c = $4.62
• Total daily benefit: $5.64

East-west split 6.6 kW:

• Daily generation: 24 kWh (87% of north-only)
• Self-consumed: 14 kWh (58% - better matches usage curve)
• Exported: 10 kWh @ 6c = $0.60
• Daily savings: 14 kWh @ 42c = $5.88
• Total daily benefit: $6.48

East-west wins by $0.84 per day, or about $307 per year - despite generating less total energy.

When north-only wins

• You have a battery (battery makes self-consumption near 100% anyway, so raw generation matters more).
• You work from home and load-shift heavily to midday (dishwasher, pool pump, washing on solar peak).
• You charge an EV in your garage at midday (rare).

When east-west wins

• No battery and no load-shifting capability.
• Typical 9am-5pm work-away household.
• High evening / morning grid consumption.

The pragmatic answer

If your roof has a good north face, use it - it remains the gold standard. If your roof only offers east-west, don't be afraid of it - in 2026 Adelaide it often produces better dollar outcomes than the textbook would suggest.