The textbook says point your panels north. The textbook was not written for a Cairns house running air conditioning until bedtime. In the tropics, panel direction is less about squeezing out the maximum yearly total and more about making power at the hours you actually use it.
We are G-Solar & Electrical, based at 32 Magazine Street in Stratford. We design and install solar across Cairns, Port Douglas, the northern beaches and the Atherton Tablelands, and roof orientation is one of the first things we look at on every quote.
Quick Answer
- North-facing panels make the most total energy over a year in Australia
- East catches morning power, west catches afternoon power. In Cairns, west is underrated
- This far north, the yearly penalty for east or west is smaller than southern guides claim
- A split array facing two directions often beats one perfect direction for real households
- Tilt around 15 to 20 degrees suits Cairns latitude, and never install flatter than about 10 degrees
- A good design matches your roof to your usage pattern, not to a rule of thumb
Why North Is the Textbook Answer
Australia sits in the southern hemisphere, so the sun tracks through the northern sky. A panel facing north sees the sun most squarely for the most hours, which is why north-facing arrays win on total annual generation everywhere in the country.
If your roof has good north-facing space, that is still the default place to start. Nothing about the tropics changes that. What changes in Cairns is how much the alternatives cost you, and the answer is: less than most guides say.
Cairns sits at about 17 degrees south. The sun here rides high in the sky for much of the year, and in the middle of summer it actually passes north of overhead. A high sun means the difference between roof faces shrinks. East and west arrays in FNQ give up only a modest slice of annual total compared to north, a smaller penalty than the same choice in Melbourne or Hobart.
The Real Question: When Do You Use Power?
Two Cairns homes with identical roofs can need opposite designs.
- Morning-heavy home. Up at dawn, aircon through the morning, out by afternoon. East panels feed that pattern, making strong power from sunrise.
- Afternoon-and-evening home. School pickup, afternoon aircon, cooking, pool pump, EV on the charger at 5 pm. West panels carry that load, holding output late into the afternoon when the east face has gone quiet.
Remember why self-use timing matters so much now: exported power earns just 6.006 cents per kilowatt hour in regional Queensland, while every kilowatt hour you use yourself avoids buying grid power at several times that. The full story is in our feed-in tariff guide and our playbook on using more of your own solar.
That is why we rate west-facing arrays so highly in Cairns. Afternoon is when FNQ homes work hardest, with air conditioning leading the charge, and a west array makes its best power exactly then. The kilowatt hours land where the money is.
The Split Array: Usually the Smart Play
Most modern Cairns installs we design use two roof faces, commonly north plus west or east plus west. A split array spreads generation across more of the day: earlier start, later finish, flatter and longer production curve instead of one big midday spike.
That shape wins for three FNQ-specific reasons:
- It matches usage. Real homes use power across the whole day, not in one midday lump.
- It plays nicely with export limits. Most Ergon-area homes can export only 5 kVA. One big midday spike slams into that cap and gets trimmed; a spread curve stays under it and wastes less. Details in our export limits guide.
- It suits batteries. A longer generation day charges a battery more steadily and still has it full by evening.
Modern inverters handle two roof faces as separate inputs as standard, and microinverters make even three or four directions workable on complicated roofs. Our inverter comparison covers which hardware suits which roof. The direction to avoid is south. This far north the penalty is real, and south faces are the last resort of a crowded roof.
Tilt: What Angle Works in Cairns
The rough rule for year-round production is to tilt panels at about your latitude, which for Cairns means around 17 degrees. In practice, most FNQ roof pitches land somewhere between 10 and 25 degrees, and panels mounted flush to those roofs perform well. Tilt frames to chase a few extra percent are rarely worth their cost and wind exposure on a house roof; in cyclone region C, low-profile flush mounting is also the sturdier choice, as our cyclone rated solar guide explains.
The one hard rule is the bottom end: never install panels flatter than about 10 degrees. Below that, rain stops sheeting off the glass properly. Water pools, dries and builds grime rings, and in our climate flat glass grows mould. Flat arrays need constant washing to stay healthy, a chore our panel cleaning guide explains in detail. On genuinely flat roofs we use low-angle tilt frames to buy back that minimum self-cleaning slope.
Shade beats every rule above. A perfectly aimed panel behind a mango tree loses to a west panel in full sun every time. That is why we check your roof, not a satellite guess, before quoting; our guide to roof suitability in Cairns covers what we look for, and how many panels you need covers the sizing that follows.
Frequently Asked Questions
What is the best direction for solar panels in Australia?
North gives the highest total annual generation. In Far North Queensland the gap to east and west is smaller than in southern states, so the best direction for your home depends on when you use power.
Are west-facing solar panels worth it?
In Cairns, very often yes. West panels peak in the afternoon when aircon load is highest and evening routines begin, which is when self-used solar saves the most money against the grid rate.
What angle should solar panels be in Queensland?
Around your latitude is the year-round ideal, roughly 15 to 20 degrees in Cairns. Standard roof pitches work well flush-mounted. The firm rule is a minimum of about 10 degrees so rain can self-clean the glass.
Can I put solar panels on two different roof faces?
Yes, and most of our Cairns designs do. Modern string inverters run two faces as separate inputs, and microinverters handle even more complex layouts. A split array spreads power across the day.
Do south-facing solar panels work in Cairns?
They produce, but noticeably less, and we treat south faces as a last resort once north, east and west space is used. A design that needs the south face usually needs a rethink instead.
Does panel direction matter less with a battery?
Somewhat. A battery soaks up whenever generation happens and time-shifts it to your usage, which softens the timing question. Direction still decides your total harvest, so it always matters.
Get a Design Based on Your Roof, Not a Rule of Thumb
We look at your roof faces, your shade, your export limit and when your household actually uses power, then aim the array where it earns most. Backed by our 10 year workmanship guarantee across Cairns and FNQ. Call 07 4039 4914 or book a free consultation.