Key takeaways
- Only three cell types matter for Indian homes in 2026: Mono PERC, TOPCon and HJT. Polycrystalline and thin film have dropped out of the home market.
- Bifacial, half-cut and glass-glass are not separate types. They are ways of building a panel, and one panel can be all three at once.
- The datasheet tells you the cell type even when the seller is vague. A temperature coefficient near −0.35%/°C and 2% first-year loss means PERC, whatever the brochure says.
- Subsidy panels need Indian-made cells, and about half of India’s approved cell capacity is still Mono PERC. So a DCR panel is more likely to be PERC than a non-DCR one.
There are three main types of solar panels sold for Indian homes today: Mono PERC, TOPCon and HJT. All three are monocrystalline silicon. They differ in how the cell is built, which shows up in efficiency, how much output they lose in heat, and how slowly they age. Polycrystalline panels, the blue ones you still see on older roofs, have all but disappeared from new installs.
Most guides stop at that list. This one also shows you how to tell the types apart from a datasheet, what Indian summer heat does to each, why your subsidy panel is likely to be PERC, and the mistakes people make with bifacial and flexible panels.
The three cell types at a glance
| Mono PERC | TOPCon | HJT | |
|---|---|---|---|
| Cell base | P-type silicon | N-type silicon | N-type silicon |
| Panel efficiency | 20.5–21.7% | 22.5–23.7% | 22.5–23% |
| Common panel sizes | 530–560 W | 580–640 W | 690–760 W (large panels) |
| Heat loss per °C | 0.34–0.37% | 0.29–0.30% | About 0.24% |
| Output promised at year 25 | About 85% | About 89% | About 91% |
| Made in India (DCR) supply | Most of it | Growing fast | One maker |
| Where you see it | Most subsidy installs so far | New installs, both DCR and non-DCR | Mostly solar farms |
Mono PERC: the workhorse
PERC stands for Passivated Emitter and Rear Cell. A reflective layer at the back of the cell bounces unused light back through the silicon for a second chance. It was the default panel in India from about 2019 until 2024, and most PM Surya Ghar systems installed so far use it.
PERC cells are made from P-type silicon, which loses a little power in the first few weeks of sunlight. That is why PERC datasheets show a 2% or bigger drop in year one. It is cheap, proven and fine for most homes. Its weak spot is heat.
TOPCon: the new default
TOPCon (Tunnel Oxide Passivated Contact) uses N-type silicon and a very thin oxide layer at the back that cuts electrical losses. In practice you get a 580 to 640 W panel in roughly the footprint of a 540 W PERC panel, less loss in heat and slower ageing. Most new panel factories in India now build TOPCon.
Whether the extra cost pays back on your roof is a numbers question we cover separately in TOPCon vs Mono PERC vs HJT.
HJT: efficient, but not built for homes yet
HJT (heterojunction) sandwiches crystalline silicon between thin layers of amorphous silicon. It handles heat best of the three and ages slowest. HJT cells entered India’s approved cell list in April 2026, with Reliance as the only listed maker.
The catch for homes is size. The HJT panels made in India today are 690 to 760 W, 2.4 to 2.6 metres long, 1.3 metres wide and 38 to 42 kg each. They are built for solar farms. Getting one up a narrow staircase, or fitting a row of them on a small terrace, is a real problem. Unless your installer offers a home-sized HJT panel, TOPCon is the practical high-end choice.
Bifacial, half-cut and glass-glass are not types
Shop listings often read like “Mono PERC half-cut bifacial” or “TOPCon bifacial glass-glass”, and many articles count these as separate kinds of panel. They are not. They are build options that sit on top of the cell type.
- Half-cut: each cell is cut in two. Lower current means less heat in the wiring, and a shadow on one half of the panel costs less output. Almost every panel sold today is half-cut, so it is no longer a reason to pay more.
- Bifacial: the back of the panel also collects light reflected off the roof. More on whether it helps you below.
- Glass-glass: glass on both faces instead of a plastic backsheet. It is needed for most bifacial panels and resists moisture well, but adds a few kilos per panel.
Read the datasheet: four lines that give away the cell type
Sellers sometimes write “N-type” or “TOPCon technology” on a quote for a panel that is really PERC, or leave the cell type off entirely. You do not need to take their word for it. Ask for the panel’s datasheet and check these four lines.
| Datasheet line | Mono PERC | TOPCon | HJT |
|---|---|---|---|
| Temperature coefficient of Pmax | −0.34 to −0.37 %/°C | −0.29 to −0.30 %/°C | About −0.24 %/°C |
| First-year degradation | 2 to 2.5% | About 1% | About 1% |
| Yearly degradation after that | 0.55 to 0.6% | About 0.4% | 0.3 to 0.375% |
| Bifaciality (bifacial panels only) | About 70% | About 80% | 85 to 90% |
If the temperature coefficient is −0.34%/°C or worse and the first-year degradation is 2% or more, it is a PERC panel. Two lines agreeing is enough. Then check that the model number on the datasheet matches the one on your quote and, for subsidy systems, on the DCR certificate.
What Indian summer heat does to each type
A panel’s rated wattage is measured at a cell temperature of 25°C. On an Indian rooftop in May the cells run 20 to 30°C hotter than the air. Take a 43°C afternoon in Nagpur or Jaipur and the cells sit at about 68°C, which is 43°C above the test condition. Multiply that by the temperature coefficient and you get the loss.
| Panel type | Loss at 68°C cell temperature | On a 3 kW system at that moment |
|---|---|---|
| Mono PERC (−0.35%/°C) | About 15% | About 450 W less |
| TOPCon (−0.29%/°C) | About 12.5% | About 375 W less |
| HJT (−0.24%/°C) | About 10% | About 310 W less |
Over a full year the gap is smaller, because mornings, winters and cloudy days are much cooler. Expect TOPCon to make roughly 1 to 3% more units a year than PERC of the same wattage, more in Rajasthan, Vidarbha and Telangana and less in Bengaluru or the hills. It also explains why a new system often produces less in May than in March, even though May has more sun. See month-by-month figures for your state in the solar generation calculator.
The subsidy twist: Indian-made cells are still mostly PERC
Panels under PM Surya Ghar must use Indian-made cells (DCR). Since 1 June 2026 those cells also have to come from a factory on the government’s approved cell list, ALMM List-II. As of July 2026 that list covered about 31 GW of cell capacity, and roughly 52% of it was Mono PERC and 33% TOPCon. India’s module factories, by contrast, have mostly moved to TOPCon.
So the panel on a subsidised roof is more likely to carry PERC cells than a non-DCR panel of the same brand. DCR TOPCon panels exist, but they cost more and are not always in stock. If your quote says TOPCon and DCR, check the datasheet as shown above before you sign. Prices for both are in solar panel price in India.
Bifacial panels on a home roof: what to expect
Bifacial panels are sold with claims of 10 to 30% extra output from the back. Those numbers assume panels mounted high above a white or light surface with plenty of open space, like a ground-mounted solar farm. A typical Indian rooftop is the opposite: panels close to a dark, waterproofed slab with little light reaching the back. There the gain is usually in the low single digits.
- Flat RCC roof, raised structure: bifacial is worth a small premium. Panels a metre or more above a roof painted with white heat-reflective coating get the most out of it.
- Panels close to a dark roof: expect very little from the back. Pay for bifacial only if the price gap is tiny.
- Tin or sheet roof, panels mounted flush: almost nothing reaches the back. A regular panel does the same job.
Why polycrystalline and thin film faded
Polycrystalline panels are made from many small silicon crystals melted together, which is cheaper but less efficient, usually 16 to 18%. The government’s approved module list sets a minimum efficiency of 19.5% for rooftop panels, so poly panels cannot be used for subsidy systems, and most factories stopped making them.
That bar is set to rise. An MNRE draft from December 2025 proposes 20.5% from 1 January 2027 and 21% from 1 January 2028 for rooftop panels. If it goes through, lower-wattage PERC panels around 20 to 20.9% efficient would no longer qualify for new subsidy installs. Panels already on your roof are not affected.
Thin-film panels (CdTe) are made in India by just one company, and they go to large solar farms. You will not be offered them for a home.
Flexible solar panels: where they fit
Flexible and semi-flexible panels are thin, light sheets, usually 50 to 150 W, that bend over a curved surface. They suit vans, boats, tents and curved shed roofs. Small ones listed on IndiaMART in 2026 mostly sell for ₹25 to ₹50 per watt, about double a regular panel, and their warranties run a few years rather than 25.
They are not on the approved list for rooftop systems, so they do not qualify for the subsidy, and they run hot because they lie flat with no air gap. For a house, a regular framed panel is cheaper and lasts far longer.
Adding panels later? Do not mix types on one string
If you expand your system in a few years, the new panels will probably be a different type and wattage. Panels wired in series on one string all run at the current of the weakest one, so a new 600 W TOPCon panel on a string of old 540 W PERC panels works like another 540 W panel. Ask your installer to put new panels on a separate MPPT input of the inverter, or on a second inverter, so neither set holds the other back.
Which type should you buy?
- Claiming the PM Surya Ghar subsidy: any DCR, ALMM-listed panel. Take DCR TOPCon if it costs only a little more than DCR PERC.
- Hot city: TOPCon over PERC. The heat gap is real in Rajasthan, Gujarat, Vidarbha, Telangana and north India.
- Small roof: the highest-wattage panel that fits, which today means TOPCon.
- Raised structure on a flat roof: bifacial glass-glass, if the premium is small.
- Not taking the subsidy: non-DCR TOPCon gives the lowest cost per watt.
- Skip: polycrystalline, and flexible panels for the main roof.
Compare panel models side by side on compare solar panels.
Frequently asked questions
How many types of solar panels are there?
For Indian homes in 2026 there are three types in practice: Mono PERC, TOPCon and HJT, all monocrystalline. Polycrystalline and thin-film panels exist but are no longer offered for home rooftops. Bifacial and half-cut are build features, not separate types.
Which type of solar panel is best for home use in India?
TOPCon is the best all-round choice in 2026. It produces more per square metre than Mono PERC, loses less in summer heat and ages more slowly. Mono PERC is still fine if it is noticeably cheaper, especially for subsidy systems.
What is the difference between monocrystalline and polycrystalline solar panels?
Monocrystalline cells are cut from a single silicon crystal and reach 20 to 24% efficiency. Polycrystalline cells are made from many crystals and reach only about 16 to 18%, which is below the 19.5% minimum for subsidy rooftop panels, so they have dropped out of the home market.
Are bifacial solar panels worth it on a home roof?
Only when the panels are raised well above a light-coloured roof. On a typical rooftop with panels close to a dark slab, the extra output from the back is usually a few percent at most, so pay for bifacial only if the price difference is small.
How can I tell if a panel is TOPCon or PERC?
Check the datasheet. TOPCon panels show a temperature coefficient around −0.29 to −0.30%/°C and about 1% first-year degradation. PERC panels show −0.34%/°C or worse and 2% or more in the first year.
Can flexible solar panels be used for the PM Surya Ghar subsidy?
No. Flexible panels are not on the approved module list for rooftop systems, so they do not qualify. They suit vans, boats and curved surfaces rather than house roofs.