Solar panels in Cherrybrook

As an estimate, a 6.6kW system comes to about $3,990, a 10kW to about $5,490 and a 13.2kW to about $7,990, with the STC discount for postcode 2126 already taken off. Those are typical figures for a straightforward install, not a fixed price. The common additions on Cherrybrook's housing stock are two-storey access and a switchboard upgrade — and if someone has suggested a three-phase upgrade as part of the job, that is a far larger number and deserves its own conversation.

Cherrybrook is in STC Zone 3, rating 1.382. In 2026 a 6.6kW system creates 45 certificates, worth roughly $1,710 off the price, and a 10kW system 69 certificates, roughly $2,622. It is a discount applied at the point of sale, not a grant you apply for afterwards, and it is calculated on capacity and postcode only — single-phase or three-phase makes no difference to it.

Open the meter box and look at the main switch. A single main switch feeding the house is the usual sign of single-phase; three linked main switches, or a main switch three poles wide, means three phases are coming in. The meter itself is another clue, and on an older board the number of incoming conductors tells you. If you are not certain, do not guess from the internet — any electrician will confirm it in a minute, and we check it at the assessment anyway because it changes what we would recommend.

It means you can export more of what it makes, which is a slightly different thing. The export allowance networks publish is per phase — on a flexible connection that is up to 10kW per phase, so a three-phase home with a three-phase inverter has headroom of up to 30kW across the three where a single-phase home has 10kW. Generation itself is not capped by your phases; what gets capped is what you are allowed to send back. On a house that uses most of its power during the day, that distinction matters far less than it sounds.

Almost never for solar alone. Bringing three phases to a house that does not have them means network work in the street as well as a new switchboard inside, and it runs to several thousand dollars — the figure depends enormously on whether three-phase is already available at your boundary. Weighed against the extra export income it would unlock at current feed-in rates, the arithmetic does not get there on its own. The upgrade earns its cost through loads, not through solar.

When you want to run something that needs it, and the solar benefit then comes along free. Ducted air conditioning on a large house, a workshop with proper machinery, a pool with substantial plant, or a three-phase EV charger that halves your charging time are the usual reasons. If one of those is already on your list, do that work first and size the solar afterwards — the order saves you paying twice for switchboard labour.

Not necessarily, but it is usually the better choice, and it is worth deciding deliberately rather than by default. A single-phase inverter on a three-phase supply works perfectly well; it just puts all its generation onto one of your three phases, so your export headroom is that one phase's allowance and your own loads on the other two are not directly offset. A three-phase inverter spreads generation across all three, which uses more of it in the house before anything is exported. The gap in price is modest; the gap in outcome depends on how your loads are distributed.

The distribution network that owns the poles and wires in your street approves it — not your retailer — and we lodge the application for you. Worth knowing here specifically: Cherrybrook sits close to a boundary between two distribution networks, and neighbouring suburbs are not all on the same one. The flexible export allowance of up to 10kW per phase is common to both, but the fixed-connection figure is not, so we confirm from your actual address which rules apply and put the limit in writing before install day rather than quoting a number that may belong to the next suburb.