Solar panels in Kirrawee

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 2232 already taken off. Those are typical figures for a straightforward install, not a fixed price. The housing here is mixed enough that a switchboard upgrade is the most common addition, and it should be in the quote rather than discovered on the day.

Kirrawee 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.

You look, and most people never do — which matters because the failure mode of solar is silence rather than noise. Nothing bangs, nothing leaks, and a system producing half what it should looks exactly like one producing all of it. The number to hold onto is what your system should make on an average day: at 4.1 kWh per kW, a 6.6kW system averages roughly 27 kWh across the year. That is an annual average rather than a daily target — summer runs well above it and winter well below — but if your monitoring is nowhere near it on clear days, something is worth chasing.

A smooth arc. Production starts after sunrise, climbs to a peak around the middle of the day and tapers off — and on a clear day the curve should be clean rather than jagged. Cloud puts sharp spikes and dips into it, which is normal. What is not normal is a flat top on a clear day, a notch at the same time every day, or a curve that simply stops partway through the afternoon. Those three shapes each mean something specific, and all three are worth a call.

A flat top usually means the inverter has reached its limit, which is expected on a well-designed system for a few hours and not a fault. A notch at the same time each day is almost always shade — a tree, an aerial, a neighbour's new addition — and it will drift through the year with the sun. A system that stops partway through the afternoon, or produces nothing at all on a bright day, is an inverter or a supply problem rather than a panel problem, and it is the one to act on quickly, because every day it sits dark is money.

Substantially, and it is not a fault. Shorter days and a lower sun angle mean a midwinter day can produce around a third of what the same system makes in midsummer. The useful habit is comparing like with like — this June against last June rather than against December — which is the only way to tell a seasonal drop from a developing problem. A year of data makes the second year easy to read.

Daily production, against what the system did on comparable days before. The share you use yourself rather than export, because that is what actually determines the value you get and it is the number you can change. And the inverter's own status or error log, which most monitoring apps will show you and which tells you about faults before a bill does. Checking those once a month takes a minute and catches almost everything that goes wrong.

With whatever monitoring was set up at installation — and if nothing was, or the login is long gone, that is fixable. Most inverters of the last decade can be connected to a monitoring portal, and an accredited installer can commission it and test the system at the same time. We do this on systems we did not install. It is also the fastest way to find out whether the years you have not been watching cost you anything.

The distribution network that owns the poles and wires in your street approves it — not your retailer — and we lodge the application for you. On a flexible export connection, a complying system up to 30kW is automatically approved to export up to 10kW per phase. On a fixed export connection, the approval is 3kW per system. If your home has no reliable internet, exports are limited to a static 1.5kW per system until a connection is available — which is also, incidentally, why monitoring and the connection type are related questions.