Types of solar panels for Melbourne roofs: mono, poly and newer cells

What is the difference between monocrystalline and polycrystalline solar panels?

Both are crystalline silicon. Monocrystalline cells are sliced from one crystal: the US Department of Energy describes cylindrical ingots pulled from molten silicon, cooled and sawn into thin wafers. Polycrystalline (also called multicrystalline) cells are cut from a block made of many small crystals, which gives them their blue, speckled look. Today the comparison is mostly history, because polycrystalline panels are no longer made in volume.

How a solar cell makes power

Why almost every panel sold today is monocrystalline

Two shifts did it. First, silicon wafers won: they made about 98% of the world’s panels in 2025, and Fraunhofer ISE says multicrystalline silicon “has disappeared from the market”. Second, makers kept changing the cell design for efficiency. The US Department of Energy says PERC cells overtook the older aluminium back-surface-field cells around 2018 because they were more efficient, and that the move from PERC to N-type designs is driven by efficiency too. Fraunhofer ISE now calls monocrystalline N-type TOPCon dominant.

You see the result on the roof. Commercial monocrystalline modules have gone from about 17% to just under 25% efficient in a decade, so the same roof holds more watts than it did. The most efficient model in each range on our list is 22.53% to 23.8% efficient.

If a quote lists polycrystalline panels, ask why, and check the model. The panels and the inverter must be on the Clean Energy Council’s list of approved products, which is another condition for STCs. Ask for the exact model numbers on the quote and check them.

Solar panel efficiency explained

N-type, TOPCon, HJT and back-contact cells

These names describe the cell inside a monocrystalline panel, not a different kind of panel. The full names come from Fraunhofer ISE’s list of abbreviations.

• N-type and P-type. The type of silicon wafer: N-type wafers are negatively doped, with phosphorus, and P-type wafers are positively doped, with boron or gallium. N-type made up 86% of the silicon wafers produced in 2025.
• TOPCon (tunnel oxide passivated contact). The N-type design Fraunhofer ISE now calls dominant. On our list: Canadian Solar TOPHiKu6 and Winaico NCX48 glass-glass.
• HJT (heterojunction with intrinsic thin layer). Also called HIT. With TOPCon, it is replacing PERC. On our list: REC Alpha Pure-RX and Phono Solar Helios.
• Back contact (interdigitated back contact). All the metal contacts sit on the back of the cell, so none block light on the front. The US Department of Energy notes these cells are harder to make, so they are a small share of production. On our list: Phono Solar Quasar.
• PERC (passivated emitter and rear cell). The P-type design that led the market before N-type cells took over. You will still find it on older systems.

On a hot Melbourne afternoon the heterojunction ranges here lose the least power: 0.24% to 0.26% per degree of cell temperature above 25°C, against 0.28% to 0.29% for the TOPCon ranges (makers’ temperature coefficients).

REC heterojunction panels

Half-cut cells, glass-glass and other datasheet labels

A datasheet also says how the cells are cut and wired and what covers their back. These are construction labels, not panel types; the layers themselves, from the front glass to the junction box, are explained in what solar panels are made of.

• Half-cut cells. Each cell is cut in two, so the panel carries twice as many smaller ones. Of these, only the REC Alpha Pure-RX datasheet says so. REC says its layout divides the panel into four sections, for more energy in shade, and reduces internal resistance.
• Busbars and wires. Busbars are the metal strips that carry current off each cell. Multi-busbar cells use more, finer ones and busbar-less cells do without them: Fraunhofer ISE lists both among the ways makers use less silver. REC says its panel uses an increased number of thin wires and solder-free cells. None of these datasheets gives a busbar count, so judge the result: efficiency, temperature coefficient and warranties.
• Glass-glass or glass-backsheet. Four of the five have glass on both sides; the REC Alpha Pure-RX has a black polymer backsheet. Phono Solar’s datasheet argues that plastic backsheets degrade and that glass replaces them, and Fraunhofer ISE lists double-glass modules as one way to avoid fluorinated backsheets. Either way, the product warranty is what covers it: compare them in our panel table.
• Shingled and lightweight panels. Neither appears on these datasheets: every range here is a framed glass panel of 22 to 25 kg. For flexible, lightweight panels, see thin film below.

For a Melbourne roof, read the labels as clues rather than reasons to buy. If trees or a neighbour’s second storey shade part of your roof for some of the day, ask how the panel layout and the inverter handle it; otherwise compare the efficiency, temperature coefficient and warranties the labels produce.

Shade and roof direction

Do bifacial solar panels help on a Melbourne roof?

Bifacial panels collect light on the back as well as the front. Winaico rates the back of its WST-465NCX48-BW at up to 80% of the front, and lists 512 W instead of 465 W with a 10% rear-side gain, “depending on irradiation conditions”.

How much of that a roof sees depends on the site. IEA PVPS Task 13’s report on bifacial systems says the gain rises with a more reflective surface under the panels, more diffuse light, a higher array and more space between rows and panels. On solar farms whose panels track the sun over natural ground it is generally under 10%, and it falls in winter, when the low sun leaves more of the ground in shadow.

A pitched Melbourne roof offers little of that. The panels sit on rails a short way above the roof and face the same way it does, so the back looks at shaded roofing rather than open, sunlit ground. Count the rear gain as a bonus there, and compare bifacial panels on their front rating and warranties. The report names elevated parking structures and fixed-tilt arrays on flat white roofs among the designs that gain, so a carport, or a tilt frame on a flat, light-coloured roof, is where a bifacial back can earn its keep. On our list, Winaico NCX48 glass-glass and Phono Solar Helios are bifacial, and the Phono Solar Quasar datasheet also gives a rear-side rating.

Bifacial, glass-glass and black are three different labels. A glass back doesn’t make a panel bifacial: the Canadian Solar TOPHiKu6 has one but is rated on the front only. Nor do bifacial cells: the REC Alpha Pure-RX puts them behind a black polymer backsheet, and its datasheet gives no rear-side rating.

Thin film, flexible and perovskite panels

Thin film

Thin-film cells are made by depositing thin layers of light-sensitive material onto glass, plastic or metal. The two main types on the market are cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) (US Department of Energy). Thin film is 2 to 3% of the world market. Commercial cadmium telluride modules have reached almost 20% efficiency, against just under 25% for monocrystalline (Fraunhofer ISE), so the same roof holds fewer watts, and CdTe and CIGS cells need more protection than silicon to last outdoors.

Flexible panels

Because thin-film layers can sit on plastic or metal, some panels bend. They are built for curved and portable surfaces. Whatever panel goes on a grid-connected home system must be on the Clean Energy Council’s approved list for the system to earn STCs, so check a flexible panel’s model number before you plan around it.

Perovskite

Perovskite cells are a newer type of thin-film cell. In the lab they rival silicon: the official records are 26.9% for a perovskite cell and 35.2% for a perovskite-on-silicon tandem cell, against 28.1% for monocrystalline silicon. The hurdle is life outdoors: the US Department of Energy says perovskite cells must become stable enough to survive 20 years outdoors to be commercially viable.

In Australia, the Australian Renewable Energy Agency (ARENA) funds a project led by the University of Sydney with SunDrive Solar that aims for a tandem module of at least 28% and runs to April 2028. ARENA says low-cost manufacturability and durability at both cell and module levels is critical before tandem cells can compete (project page). The silicon panels on our list carry 25 to 30-year performance warranties from their makers today.

Plug-in (balcony) solar: can you use it in Victoria?

Not yet, as at November 2026. Plug-in solar is a small kit of panels and an inverter that plugs into a power point, often sold for balconies. Inverters connected to the grid in Australia have to meet AS/NZS 4777.1:2024, and the Western Australian Government’s consultation paper (28 October 2026) notes that it requires inverters to be permanently wired, which currently leaves no viable certification pathway for plug-in systems. Because the standard is national, that applies to a Melbourne home too. In Victoria, home solar is installed by a licensed A-grade electrician (Energy Safe Victoria).

Western Australia is consulting on a way through for WA homes: a draft Technical Bridging Standard for up to 2 kW of panels and inverters up to 800 VA, with no cap on battery storage. Submissions close at 5pm AWST on 9 December 2026. For now, its FAQ says, it remains illegal to use imported systems, and WA will seek to move the standard to a nationally consistent one through the Australian Standards process. If you rent or live in an apartment, see what Solar Victoria offers instead.

Solar for renters and apartments

Solar roof tiles vs solar panels

Solar roof tiles (also sold as solar tiles or solar shingles) are building-integrated solar, or BIPV: the cells are part of the roof covering itself, instead of panels fixed on rails above the roof you already have.

That matters for rebates. Solar Victoria defines BIPV as integrated solar panel walls, facades and roofs and any associated equipment, and its Solar Homes Program terms say BIPV is not an eligible system and is not on its approved product list. So solar roof tiles don’t get Solar Victoria’s solar panel rebate (up to $1,400) or its loan. Federal STCs are a separate question: as with any panel, the tile model must be on the Clean Energy Council’s approved list for the system to earn them.

Tiles also turn solar into a roofing job: the roof has to be replaced, or built, to take them. If your roof is sound, panels on rails are the simpler way to add solar. If you are re-roofing or building, compare an integrated product’s rated watts, warranties and rebate eligibility with panels on the new roof before you decide.

Solar rebates in Victoria

How STCs work

Which type of solar panel we install

The panel ranges we list with full datasheets are from Canadian Solar, REC, Winaico and Phono Solar, the brands our previous site listed; your quote confirms the exact model. All 5 are monocrystalline and N-type: 2 TOPCon, 2 heterojunction and 1 back contact, 2 of them bifacial. None uses polycrystalline or thin-film cells, and none is a roof tile.

We choose the panel for your roof, your budget and the look you want, and the quote names the model so you can check its datasheet. Panels are only part of a system’s price; see the solar panel cost guide.

Compare the panels we install

See our solar packages

Solar panel types: your questions