What a 6.6kW solar system costs in Cairns (October 2026)
Installed and GST inclusive with Tier 1 panels and a quality string inverter, a 6.6kW system in Cairns is $5,780–$8,400 after the federal STC discount of $2,133 (STC Zone 1). That is $7,913–$10,533 before the discount, which the installer takes off the quote.
| Tier | Installed after STCs | Per watt |
|---|---|---|
| Budget | $4,770–$6,932 | $0.89/W |
| Mid-range (most quotes) | $5,780–$8,400 | $1.07/W |
| Premium | $7,576–$11,010 | $1.41/W |
Cairns runs about 5% above the national average for this size and these prices include cyclone-rated mounting. Full breakdown by size and tier on the Cairns solar cost page.
How much a 6.6kW system generates in Cairns
With 5.4 peak sun hours a day, 15 panels (6.6kW) in Cairns produce about 10,146 kWh a year — roughly 27 kWh a day averaged across the year, more in summer and less in winter.
Using about 40% of that on site at 30c/kWh and exporting the rest at 5.0c saves $1,370–$1,900 a year, for a payback of 3.7–5.2 yrs. Shift the dishwasher, washing machine and hot water into daylight hours and you land at the short end.
Is 6.6kW the right size for your Cairns home?
6.6kW suits the typical 3–4 person home — still the most installed size in Australia. As a rule of thumb it matches a quarterly electricity bill of $450–$750 or daily use of 15–22 kWh.
- Roof space: about 30m² of unshaded roof for 15 × 440W panels, ideally north, or split east/west
- Inverter: a 5kW inverter (the 6.6kW/5kW pairing maximises the STC discount on single-phase)
- Export limits: most QLD networks cap single-phase export at 5kW — not an issue at this size
- Going bigger: cost per kW falls with size, so if the roof allows, 8kW is often only a little more per month on finance
Not sure? The free Cairns solar score sizes the system from your bill and household.
6.6kW solar with a battery in Cairns
A 6.6kW array pairs naturally with a 10kWh battery. Adding one costs $6,984–$9,984 after the federal battery discount of $2,516, and shifts about 8 kWh of solar into the evening each day — worth roughly $730 a year at Cairns tariffs. Solar and battery as one job in Cairns: $12,764–$18,384.
Brand-by-brand installed prices are in the battery guide.
Rebates on a 6.6kW system in QLD
- Federal STC discount: $2,133 on 6.6kW in Zone 1 (6.6 kW × 1.622 × 5 years × $39.85). Deeming drops to 4 years on 1 January 2027, cutting this by about $427.
- QLD: Queensland's STC zone rating — Zone 3 in the south-east and Zone 1–2 in the north, among the highest in the country.
- Battery: $252 per usable kWh under the federal Cheaper Home Batteries program.
Other sizes in Cairns and 6.6kW elsewhere
Other sizes in Cairns
6.6kW in other cities
Solar in Cairns — suburbs, installers and rebates → · 6.6kW national guide →
6.6kW in Cairns: common questions
How much does a 6.6kW solar system cost in Cairns?
$5,780–$8,400 installed after the $2,133 federal STC discount, for Tier 1 panels and a quality inverter (October 2026). Premium panels with micro-inverters run to about $11,010.
How many panels is a 6.6kW system?
15 panels at today's 440W size, needing about 30m² of roof. Older 370–400W panels would mean 17.
How much power does 6.6kW produce in Cairns?
About 10,146 kWh a year — 32 kWh a day in the best month and 25 in the worst — on an unshaded north-facing roof.
What is the payback on a 6.6kW system in Cairns?
3.7–5.2 yrs, saving $1,370–$1,900 a year at 30c/kWh. A battery lengthens payback slightly but lifts the saving.
Get 6.6kW quotes in Cairns
The free solar score checks whether 6.6kW is the right size for your bill and roof, shows the Cairns price range, and — only if you ask — shares your enquiry with up to two CEC-accredited local installers. Get my solar score →