How much is the solar rebate worth? STCs explained for 2026

There’s no form to fill in and no income test. When an eligible solar system is installed, it creates certificates, and you usually swap them for a lower price on your quote. The certificates are assigned to the property address, not the owner, and their value depends on three things: how big the system is, where you live, and the year it’s installed.

How many certificates will your system earn?

Each system earns certificates for the electricity it’s expected to generate between installation and the end of 2030. The Clean Energy Regulator’s calculation works like this:

Your zone rating reflects how much sun your area gets. Australia is split into four zones by postcode, and you can look yours up in the regulator’s postcode zone ratings table.

Worked example: a 6.6 kW system installed in 2026

A 6.6 kW system is a common size for homes because it pairs with a 5 kW inverter. Here’s roughly what it earns in each zone, valued at the $33–$38 per certificate the regulator says agents usually pay:

For the exact number for your postcode and system, use the REC Registry’s small generation unit STC calculator.

Why the rebate shrinks every year

The deeming period counts the years left until the scheme ends in 2030, so it drops by one every 1 January:

A system installed in December 2026 earns a quarter more certificates than the same system installed in January 2027. That’s a reason not to drift, but not a reason to rush into a quote you haven’t checked.

What makes a system eligible

According to the Clean Energy Regulator’s rooftop solar rules, a system must:

• be under 100 kW and produce less than 250 MWh a year
• use panels and an inverter on the Clean Energy Council’s approved lists, and meet Australian standards
• be installed by an accredited installer
• be new: second-hand systems don’t qualify.

One more rule shapes system sizes: the panels can be no more than 33% bigger than the inverter for the certificates to apply. That’s why 6.6 kW of panels on a 5 kW inverter is so common.

Larger systems are changing too: from 1 October 2026, systems of 100 kW to 1 MW can also claim certificates, which mostly matters for businesses and farms.

How to check the discount on your quote

The discount should be a separate line on the quote, so you can check it. Look for:

• the number of certificates, which should match the calculator for your postcode and system size
• the price per certificate, usually $33–$38
• any state rebate on its own line, such as Victoria’s solar panel rebate, which is calculated after the STC discount.

If you’re in Victoria, read our guide to the Solar Victoria solar panel rebate. Batteries and efficient hot water systems also earn certificates: see how the battery discount works and heat pump vs solar hot water.

This guide is general information, not financial or legal advice. Rules, rebates and prices change, so check the linked sources before you decide. Facts checked 18 October 2026.