What affects the cost of solar?
Two quotes for the "same size" system can differ by thousands of dollars. The usual reasons:
- System size (kW) — more panels cost more in total, but usually less per kW.
- Panels and inverter — brand, efficiency, warranty length and inverter type all move the price.
- Your roof — tile, steep pitch, two storeys, multiple roof faces or a flat roof needing tilt frames add labour.
- Switchboard work — older switchboards sometimes need upgrading before solar can be connected.
- STC discount — the federal certificate discount depends on your location and the year of installation, and it reduces each year.
- Network export limits — your distributor may limit how much you can export, which affects the best design.
For indicative price ranges, see our solar panel cost guide.
What size system do you need?
The right size depends on when and how you use electricity, your roof space, whether you plan to add a battery or EV, and your network's export rules. As a starting point:
| System size | Often suits |
|---|---|
| 6.6 kW | Small to medium homes with moderate daytime use |
| 8–10 kW | Larger households, homes adding a battery, heat pump or EV |
| 13 kW+ | High-use or fully electric homes; often needs three-phase power or export limits |
A good installer will look at your bills (or smart-meter data) and roof before recommending a size — be wary of anyone quoting without either.
Panel and inverter options
| Option | What it is | Worth considering when… |
|---|---|---|
| String inverter | One central inverter for all panels | Your roof is mostly unshaded and faces one or two directions |
| Microinverters | A small inverter on each panel | Partial shade, several roof faces, or you want panel-level monitoring |
| Optimisers | Panel-level electronics feeding a central inverter | Some shading, but you prefer a central inverter |
| Hybrid inverter | Inverter that can also run a battery | You plan to add a battery soon |
Solar rebates and incentives
Federal — Small-scale Renewable Energy Scheme (STCs). Eligible systems create small-scale technology certificates, usually applied as an upfront discount on your quote. The number of certificates depends on system size, location and installation year, and steps down each year until the scheme ends in 2030. Clean Energy Regulator — Small-scale Renewable Energy Scheme
Victoria — Solar Homes Program. Eligible households can get a rebate of up to $1,400 for solar PV (or an equivalent interest-free loan). From 1 July 2026 the combined household income cap is $150,000 per year. Solar Victoria — Solar Homes Program update
Other states and territories run their own programs from time to time. The federal energy.gov.au — Rebates and assistance finder lists current programs by location.
Last checked 21 October 2026. Programs change often — always confirm eligibility with the program and your installer.
How to compare solar quotes
Ask every installer for the same information so you can compare like for like:
- The installer's licence and any required accreditation, with numbers you can check.
- An itemised quote: exact brands and model numbers, quantities and what's included.
- Any rebate or certificate discount shown as a separate line, with who claims it.
- Product warranty, performance warranty (if relevant) and the installer's workmanship warranty — in writing.
- Who handles network/connection approvals and compliance certificates.
- Deposit amount, payment schedule and what happens if the job is delayed.
- Confirmation that the system is designed and installed by a Solar Accreditation Australia (SAA) accredited installer.
- Whether the retailer is a signatory to the New Energy Tech Consumer Code (NETCC).
Sold at your door or over the phone? Under Australian Consumer Law, unsolicited sales agreements generally come with a 10 business day cooling-off period. ACCC — consumer rights and unsolicited selling
Frequently asked questions
How many quotes should I get?
Three is a good number — enough to see a fair price range and compare advice without being overwhelmed.
Can I get solar if I'm renting?
You'll need the owner's permission. In Victoria, Solar Homes has had options for rental properties — check the current eligibility on the Solar Victoria website.
Will solar work on a cloudy day?
Yes, but output drops. Annual output depends on your location, orientation and shading — ask installers for a written yield estimate.
Should I add a battery at the same time?
It can save on installation costs if you choose a hybrid inverter. Read our battery quotes page to see whether it suits you.