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Short answer: the cost of a solar installation in Melbourne depends mostly on system size, the brands of panels and inverter, your roof, any electrical upgrades, and whether you add a battery. Federal STCs reduce the price of every eligible system, and some households can also claim Solar Victoria’s solar panel rebate. Because these factors vary so much between homes, an itemised quote based on a site assessment is the only reliable way to know your price.

1. System size

Larger systems cost more in total but usually less per kilowatt, because fixed costs such as travel, design, paperwork and the inverter are spread over more panels. Size should follow your electricity use and plans, not a standard package. Melbourne systems produce about 3.6 kWh per kW of panels per day on average across the year.

2. Panels and inverter

Brand, efficiency, temperature performance and warranty terms all affect price. A hybrid inverter that can run a battery costs more than a standard string inverter, and microinverters or optimisers add cost again. Paying more makes sense when it solves a real problem, such as a shaded or small roof. You can see the equipment we work with on our solar panels and solar inverters pages.

3. Your roof

• Roof type: tiled, metal and flat roofs need different mounting hardware and labour.
• Height and pitch: two-storey or steep roofs need more safety equipment and time.
• Layout: panels spread across several roof faces need more cabling and design work.
• Flat roofs: tilt frames add materials and engineering.

4. Electrical work

Older switchboards may need upgrading before solar can be connected safely. Longer cable runs, meter reconfiguration and making the system compliant with Victoria’s emergency backstop requirements can also affect the price. A good installer identifies these at the site assessment rather than after you sign.

5. Adding a battery

A battery is often the largest single addition to a quote. Its price depends on usable capacity, power output, backup capability and whether the existing inverter is compatible. Eligible batteries can receive a discount through the federal Cheaper Home Batteries Program, which is based on usable capacity and steps down on a set schedule.

How incentives reduce the price

• STCs: the number of certificates depends on system size, your postcode zone (most of Melbourne is Zone 4) and the deeming period, which is five years for systems installed in 2026. Most households assign the certificates to the retailer, who takes their value off the invoice.
• Solar Victoria: eligible households can claim a solar panel rebate of up to $1,400, plus an optional interest-free loan. From 1 July 2026, the combined household income cap is $150,000, and eligibility must be approved before installation.

How to read a quote

• Check that panels, inverter and any battery are listed by brand and model number.
• Look for each incentive shown on its own line, including the number of STCs.
• Confirm what is included: mounting, switchboard work, metering, monitoring set-up.
• Ask what is excluded and what could change the price after the site visit.
• Compare warranties as well as the total.

Frequently asked questions

Why do quotes for the same system size differ so much?

Different products, roof assumptions, inclusions and warranty support. Compare line by line rather than on the total alone.

Is the cheapest quote the best value?

Not necessarily. Check the products, exclusions and who will do the installation.

Will the price go up next year?

The STC deeming period falls by one year on 1 January, so the same system creates fewer certificates in 2027. Equipment prices also change, so we cannot predict overall prices.

Get an itemised quote

Cosmic Solar provides itemised quotes for solar panel installation and residential solar systems across Melbourne. Browse our installation packages or request a quote and we will explain every line.

Sources

• Clean Energy Regulator – Calculate STC entitlements (checked 29 Oct 2026)
• Solar Victoria – Solar Homes Program settings (checked 29 Oct 2026)
• DCCEEW – Cheaper Home Batteries Program (checked 29 Oct 2026)
• Energy Victoria – Emergency backstop mechanism (checked 29 Oct 2026)

General information only. Prices and incentives depend on your property and eligibility.