What a 5kW solar system costs in Cairns (October 2026)
Installed and GST inclusive with Tier 1 panels and a quality string inverter, a 5kW system in Cairns is $4,720–$6,930 after the federal STC discount of $1,616 (STC Zone 1). That is $6,336–$8,546 before the discount, which the installer takes off the quote.
| Tier | Installed after STCs | Per watt |
|---|---|---|
| Budget | $3,895–$5,719 | $0.96/W |
| Mid-range (most quotes) | $4,720–$6,930 | $1.17/W |
| Premium | $6,186–$9,083 | $1.53/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 5kW system generates in Cairns
With 5.4 peak sun hours a day, 11 panels (5kW) in Cairns produce about 7,686 kWh a year — roughly 21 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 $1,040–$1,440 a year, for a payback of 4.0–5.6 yrs. Shift the dishwasher, washing machine and hot water into daylight hours and you land at the short end.
Is 5kW the right size for your Cairns home?
5kW suits couples and small families with a modest daytime load. As a rule of thumb it matches a quarterly electricity bill of $300–$500 or daily use of 10–16 kWh.
- Roof space: about 22m² of unshaded roof for 11 × 440W panels, ideally north, or split east/west
- Inverter: a 5kW inverter; three-phase advised above 10kW
- 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, 10kW 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.
5kW solar with a battery in Cairns
A 5kW 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: $11,704–$16,914.
Brand-by-brand installed prices are in the battery guide.
Rebates on a 5kW system in QLD
- Federal STC discount: $1,616 on 5kW in Zone 1 (5 kW × 1.622 × 5 years × $39.85). Deeming drops to 4 years on 1 January 2027, cutting this by about $323.
- 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 5kW elsewhere
Other sizes in Cairns
5kW in other cities
Solar in Cairns — suburbs, installers and rebates → · 5kW national guide →
5kW in Cairns: common questions
How much does a 5kW solar system cost in Cairns?
$4,720–$6,930 installed after the $1,616 federal STC discount, for Tier 1 panels and a quality inverter (October 2026). Premium panels with micro-inverters run to about $9,083.
How many panels is a 5kW system?
11 panels at today's 440W size, needing about 22m² of roof. Older 370–400W panels would mean 13.
How much power does 5kW produce in Cairns?
About 7,686 kWh a year — 24 kWh a day in the best month and 19 in the worst — on an unshaded north-facing roof.
What is the payback on a 5kW system in Cairns?
4.0–5.6 yrs, saving $1,040–$1,440 a year at 30c/kWh. A battery lengthens payback slightly but lifts the saving.
Get 5kW quotes in Cairns
The free solar score checks whether 5kW 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 →