The short chain
A household system is five decisions in a row:
- Modules on a mounting system convert sunlight to DC.
- An inverter (string, hybrid, or micro) converts that DC to AC at the switchboard.
- Your loads use what they can in real time.
- Leftover AC is exported, if the network allows it, at a feed-in tariff set by your retailer.
- A meter and a retail plan decide what that export is worth — not the panel brochure.
Nothing in that chain is a guaranteed bill cut. Heat, dirt, shade, export limits, and when you run the air-conditioner all move the outcome. A January afternoon in Mildura is not a June morning in Ballarat. We will not invent a household kWh saving from a stock photograph of a blue roof.
Orientation: north is classic, east-west is not wrong
In most of Australia a clear northerly pitch still maximises annual energy. That is a geometry fact for the southern hemisphere, not a sales ranking. Houses from Perth to Brisbane still get the classic advice: point the array at the equator if the roof allows it and the shade map is clean.
East-west arrays spread generation into the morning and afternoon. If you are out at midday and home for the school run, that shape can match your loads better than a peak at noon. Split arrays — some north, some west — are common on hip roofs in Australian suburbs.
South-facing planes are usually last resort unless you have no other roof. They still generate; they generate less, especially in winter at higher latitudes (Melbourne, Hobart, Canberra).
Shade from a neighbour’s tree, a chimney, a vent, or a two-storey extension will beat a textbook orientation argument. Ask the designer for a shade assessment, not a stock north-facing render. The east-west versus north essay walks the trade-off without promising a yield.
Seasons and the Australian sun
Summer irradiance is high across the mainland. That is also when many households run cooling. Winter sun sits lower: more shade from the house next door, more soiling after a dry spell, less generation on a short Hobart day. The wet season in Darwin and far-north Queensland brings cloud and cleaning questions that a Sydney brochure does not mention.
Soiling — dust inland, salt on the coast, pollen in spring — reduces output until rain or a qualified clean. Do not walk a tiled roof to hose a live array. See the FAQ on maintenance.
String, hybrid, and module-level conversion
- String inverter — one conversion point for a series of modules. Clean on simple, unshaded roofs. Multiple MPPTs let a designer put east and west strings on separate inputs.
- Hybrid inverter — can manage PV and a battery. “Hybrid-ready” on a quote is not the same as a battery already being in the scope.
- Microinverters (or DC power optimisers) — conversion or electronics at the module. Useful on mixed orientations and partial shade.
See the inverter guide and the architecture essay. The roof should pick the architecture.
Export limits and the DNSP
Your Distribution Network Service Provider can cap how many kilowatts you export. In New South Wales that may be Ausgrid, Endeavour Energy, or Essential Energy. In Queensland, Energex or Ergon. In Victoria, the urban distributors (CitiPower, Powercor, United Energy, Jemena, AusNet). In South Australia, SA Power Networks. In Western Australia, Western Power on the south-west grid. Tasmania has TasNetworks; the ACT has Evoenergy; the Northern Territory has Power and Water.
That cap is a connection condition, not a broken inverter. It shows up more often as suburbs fill with rooftop PV. A quote that ignores a known export limit is not a complete quote. Read export limits.
What this page will not do
We will not invent a household kWh saving, a payback year, or a “typical 6.6 kW produces X.” Those numbers need your tariff, your usage shape, and a site design. Use this page to understand the mechanism. Use a CEC-accredited designer for the model. Use the cost guide to size from the bill rather than from a neighbour.
From the switchboard to the bill
The chain does not end at the inverter. The switchboard, the meter, and the retailer plan decide whether leftover generation is a credit you can recognise on a bill. A household on a time-of-use plan in western Sydney is not the same as a controlled-load hot-water customer in regional Victoria. The physics of the modules is shared; the contract is not.
Ask the designer to say, in writing, whether they have assumed a smart meter already exists, whether the retailer must be notified, and whether the DNSP application is in the scope. Those are not “admin extras.” They are the last two steps of the chain on this page.
If you are comparing a north-only layout with an east-west split, write down when the dishwasher, the pool pump, and the air-conditioner actually run. A noon peak that exports at a low feed-in tariff can look impressive on a generation graph and still leave you buying evening power. That is why this guide refuses a household kWh promise.
Australian weather, not a stock render
January glare on a dark metal roof in Mildura, a June frost on a Canberra tile plane, and a February downpour in Cairns are different operating days. Heat cuts real output versus the nameplate. Cloud and the wet season cut hours. Dust after a dry inland spell sits until rain or a qualified clean. None of that is a reason to climb the roof. It is a reason to treat a summer-only monitoring screenshot as incomplete.
Pair this page with east-west versus north, export limits, and maintenance. If you are ready to talk money, open the cost guide and the rebates page before you sign.
A commercial reader should stop here and go to commercial solar. A house quote scaled by floor area is the wrong fork.
Self-consumption is the quiet variable
Generation graphs look impressive at noon. Bills move when you use that energy or store it. A household that runs the washing machine, the pool pump, and the dishwasher in daylight often sees more movement than a household that exports everything and imports everything after dark. That is not a moral ranking. It is why east-west versus north and batteries are load-shape conversations, not trophy conversations.
We still will not invent your kWh saving. We will tell you to hand annual kWh, the weekday shape, and the roof after setbacks to a designer. The cost guide is the money version of that sentence.
What “grid-tied” quietly assumes
Most Australian homes are grid-tied. They export leftover AC if the network allows it. They import at night. Off-grid and generator-hybrid stories are different designs with different licences. Do not let a pump-pole brochure blur those rules. See pole mount and inverters.
A last orientation check
If the only clean plane faces south in Hobart, say so on the brief. If the only clean plane faces west in Perth, say so. The designer can still build a system; they cannot invent a north rectangle. We will not invent the kWh that rectangle would have made.
General information only. Confirm connection rules with your DNSP and compare retail plans on Energy Made Easy. Last reviewed 25 September 2026.