If you’ve collected quotes recently, almost every panel on them will be N-type. The change happened quickly and quietly, and it’s already done. N-type panels lose less output when the roof gets hot, they degrade more slowly over their life, and they hold their rating better in the first few weeks. The differences are real and worth understanding, but they’re measured in a few per cent rather than a transformation, and anyone telling you otherwise is selling.
What TOPCon changes inside the cell
Silicon on its own doesn’t do much. To make a solar cell, the silicon is doped with another element to give it an electrical charge. P-type cells are doped with boron. N-type cells are doped with phosphorus. That’s the whole distinction, and everything else follows from it. If you want the older framing of monocrystalline against polycrystalline, our post on types of solar panel covers that ground.
Boron has a problem. It reacts with oxygen trapped in the silicon during manufacturing, and that reaction costs output in the first days of sun exposure. It’s called light induced degradation, and it’s why a P-type panel gives back about 2 per cent in its first year. Phosphorus doesn’t do this, so N-type panels barely move.
TOPCon is the cell design built on the N-type wafer. It adds an ultra-thin oxide layer and a passivated contact on the rear of the cell, which stops electrons being lost where the metal contacts meet the silicon. The practical result is that more of the power the cell generates makes it off the panel. You don’t need the physics beyond that. What matters is the three numbers it changes on the datasheet.
Heat, and why temperature coefficient matters more here
Panels are rated at a cell temperature of 25 degrees. Your roof does not operate at 25 degrees. On a 40 degree Hunter day, the back of a panel on a dark Colorbond roof sits around 65 degrees, and output falls away from the rating as it climbs.
Temperature coefficient is the number that tells you how fast. It’s expressed as a percentage of output lost per degree above 25.
Take that 65 degree panel, 40 degrees above its rating point. A P-type panel at minus 0.35 per cent per degree is producing about 14 per cent below its rated output. An N-type TOPCon panel at minus 0.30 is about 12 per cent down. Jinko’s current Tiger Neo 3.0 is rated at minus 0.26, which puts it closer to 10 per cent.
Two percentage points doesn’t sound like much. On a 6.6 kW array it’s roughly 130 watts at the moment you’re running the air conditioning hardest, and Australian roofs spend a lot of the year well above 25 degrees. This is the single best argument for N-type in this country, and it’s a much weaker argument in northern Europe, which is where a lot of the marketing copy originates.
One correction worth making. You’ll see it claimed that every degree above 25 costs one per cent of output. That’s roughly three times the real figure. Check the temperature coefficient on the datasheet rather than trusting the rule of thumb.
Degradation over 25 and 30 years
Every panel produces less each year. The useful comparison isn’t the annual rate on its own, it’s where you land after two decades.
Jinko publishes warranty terms for both its N-type and P-type modules in the same Australian document, which makes for an unusually clean comparison.
| Warranty term | N-type Tiger | P-type Tiger |
| First year degradation | 1.00% | 2.00% |
| Annual degradation after year 1 | 0.40% | 0.55% |
| Performance warranty length | 30 years | 25 years |
| Guaranteed output at year 25 | 89.4% | 84.8% |
| Guaranteed output at year 30 | 87.4% | Not covered |
Run those figures out. An N-type module guaranteed at 99 per cent after year one, losing 0.4 points a year, sits at 89.4 per cent in year 25. A P-type module starting at 98 per cent and losing 0.55 points a year is at 84.8 per cent. That’s a gap of 4.6 percentage points of your original output, from the same manufacturer’s own guarantee.
Two things to keep in mind. These are warranty floors, not predictions, and most panels comfortably beat them. And a 4.6 point gap on a 6.6 kW system is a few hundred kilowatt hours a year by year 25, which is worth having but won’t change your life. It’s one input among several, which is the same conclusion we reached on whether panel quality really matters.
Reading a panel datasheet without getting lost
Four numbers do most of the work, and one of them is a trap.
The trap is wattage. A 510 watt panel is not better than a 475 watt panel, it’s usually just bigger. Efficiency is the number that tells you how much power comes off each square metre, and on a roof with limited space that’s what decides how much you can fit. Compare efficiency and physical dimensions, not the headline watts.
Then check the temperature coefficient of Pmax, the first year degradation figure, and the annual rate after that. Those three tell you how the panel behaves in Australian heat and how much you’ll still have in twenty years.
Watch the two warranties, because they are different things. The product warranty covers the panel failing. The performance warranty covers it producing less than promised. Jinko’s N-type modules carry a 30 year performance warranty, and a product warranty of either 15 or 25 years depending on which model you’re quoted. Ask which one is on your quote.
On bifacial, be sceptical. A bifacial panel generates from its rear face as well, which is worth real money on a ground mount over light gravel. On a standard pitched tile or Colorbond roof with the panel sitting close to the surface, rear side gain is close to nothing. It’s a genuine technology being sold into the wrong application.
What we install and why
We fit Jinko Solar panels across most residential jobs. The Tiger Neo is N-type TOPCon, the temperature performance suits the Hunter, and the 30 year performance warranty is the longest in its price bracket.
The sizes that go on houses are the 475 watt and 510 watt modules. If a quote puts 670 watt panels on your roof, something is wrong: those are utility scale modules built for ground mounted farms and they don’t belong on a residential rooftop. You can see the rest of the solar panels we install alongside them.
Whatever brand you’re quoted, check it appears on the Clean Energy Council approved modules list. If it isn’t there, it can’t be installed here and it won’t attract certificates.
Frequently asked questions
Should I replace working P-type panels with N-type?
No. The gap is a few per cent, and you’d be throwing away a working asset with years of warranty left to chase it. N-type matters when you’re buying, not when you already own.
Are N-type panels more expensive?
Slightly, and the gap has narrowed to the point where it rarely decides a quote. Most manufacturers have moved their volume to N-type, so it’s becoming the standard rather than the upgrade.
Do N-type panels work better on cloudy days?
They hold up a little better in low light, which is a genuine if modest advantage. It won’t rescue a badly shaded roof. Panel choice never fixes a shading problem.
Is polycrystalline still worth considering?
It has all but disappeared from Australian residential rooftops. If a quote offers it, the quote is either years out of date or someone is clearing old stock.
Find out what suits your roof
Send us your address and we’ll put together a quote with the panel specs written out in plain language, so you can see what you’re comparing. Request a quote or call 1300 992 922.
