STC zones rate how much solar resource the Clean Energy Regulator attributes to your postcode when creating Small-scale Technology Certificates. Higher zones mean more certificates — and a larger federal discount — for the same system size. In 2026, with only four deeming years left, zone differences still matter, but they no longer dwarf the rest of your quote the way they did a decade ago.
Tell us about your home. We'll match you with 3 local installers.
Indicative 2026 pricing: a typical 6.6kW system often quotes around $5,000–$8,000 after the STC discount (metro installs often $5,000–$7,500; premium/regional can run higher). See our solar cost guide.
Free for homeowners. Participating installers pay MrSolar a lead fee when matched — that does not buy a higher ranking in our guides or reviews. See how we match quotes and is MrSolar legit?
Zone 1 covers the highest irradiance pockets (think Darwin and far-northern QLD/WA). Zone 2 includes much of northern/regional high-sun Australia (NT defaults often sit here in planning tables). Zone 3 covers many major capitals: Sydney, Brisbane, Perth, Adelaide and Canberra. Zone 4 is the lowest multiplier band used for Melbourne and Hobart. Always confirm your exact postcode in the CER zone tool — suburb folklore is not paperwork.
Using MrSolar's reference table (STC spot about $39.85 as of 5 August 2026), a 6.6kW system is roughly $1,674 in Zone 1, $1,594 in Zone 2, $1,435 in Zone 3 and $1,235 in Zone 4 after typical rounding. A 10kW array scales similarly ($2,550 / $2,431 / $2,192 / $1,873). Zone 4 homes still buy solar successfully — they simply should not be sold Zone 3 rebate fantasies.
STC zone affects the upfront discount. Annual kWh yield follows real irradiance, roof orientation, shade and temperature. Hobart (Zone 4) has fewer certificates and fewer peak sun hours than Perth (Zone 3), so both discount and generation differ. Model payback with your retailer tariff and self-consumption, not zone marketing alone.
Watch for installers applying last year's deeming years, the wrong zone, or an optimistic spot price. Border towns and some regional postcodes surprise people. If two CEC-accredited quotes disagree on the STC line by hundreds of dollars for identical kW, ask both to show zone + deeming + $/STC assumptions.
The Cheaper Home Batteries Program (~$372/kWh usable since 1 July 2025) uses its own certificate-style discount logic for eligible storage. Do not assume your PV STC zone dollars automatically describe the battery line. Keep solar STC and battery subsidy as separate rows on every proposal.
Fix system size and postcode first, then compare hardware and workmanship. Zone maths should converge across reputable quotes. MrSolar introductions are postcode-aware so CEC-accredited installers price the federal discount for your actual location rather than a national average.
Get zone-correct STC pricing — compare CEC-accredited quotes for your postcode on MrSolar.
Written and reviewed by Daniel (Marketplace lead, Epic Unicorn Pty Ltd). We build pages from Australian solar datasets and regulatory references, then map you to CEC-accredited installers only.
Join over 230,000 Australian homeowners who've used MrSolar to find their installer. No obligation, no spam — just competitive quotes from CEC-accredited professionals.
Get My Free Quotes →Takes 2 minutes. Free forever. CEC-accredited installers only.