Types of solar panels explained: mono PERC, TOPCon, bifacial, half-cut and more

Walk into any conversation about rooftop solar and you will hear a string of letters: PERC, TOPCon, N-type, bifacial, half-cut, DCR. Salespeople use them as if everyone knows what they mean. Most people do not, and they end up choosing a panel on price alone or on whichever word sounded most impressive.

This guide explains the main types of solar panels you will be offered in India today, what actually differs between them, and how to decide which one makes sense for a home or business roof in Telangana or Andhra Pradesh. It is written for homeowners, not engineers, so we keep the physics light and focus on what changes for you.

The one-minute version

Almost every rooftop panel sold in India today is a crystalline silicon panel. Within that family, the differences come down to three questions:

1. How the silicon cell is made, which decides efficiency and how the panel ages. Mono PERC and TOPCon are the two you will meet most.
2. How the cells are cut and arranged, which decides how the panel copes with shade and heat. "Half-cut" is the common term here.
3. Whether the back of the panel also collects light. Monofacial panels collect light only on the front; bifacial panels collect it on both sides.

For a typical home on a flat terrace, a good-quality mono PERC or TOPCon panel from an established manufacturer, installed properly, is the right answer. The difference between technologies matters less than the quality of the manufacturer, the warranty, and the installation.

First, the old split: monocrystalline vs polycrystalline

You may still see "mono" and "poly" in quotes, so it is worth knowing what they mean.

Polycrystalline panels are made from silicon melted together from many crystals. They have a speckled, bluish look. They were cheaper for years, but they are less efficient, and most manufacturers have moved away from them.

Monocrystalline panels are made from a single crystal of silicon. They look uniformly dark, are more efficient, and handle heat slightly better. Today almost all mainstream rooftop panels are monocrystalline in some form.

If someone offers you polycrystalline panels in 2026, ask why. They are not necessarily bad, but they are older technology, and you would want a clear price advantage to accept the lower output per square metre of roof.

Mono PERC: the workhorse

PERC stands for Passivated Emitter and Rear Cell. Without the jargon, PERC adds a layer to the back of the cell that reflects light which passed through the silicon back into it, giving the cell a second chance to turn it into electricity. That small change made monocrystalline panels noticeably more efficient, and mono PERC became the standard rooftop panel for most of the last decade.

What it means for you:

• Proven. Mono PERC has been installed on millions of roofs. Its behaviour over the years is well understood.
• Good value. Because it is mature, it is usually priced well.
• Fine for most homes. On an unshaded Hyderabad or Anantapur terrace, a good mono PERC system will meet the needs of most families.

Its main weakness compared with newer cells is a slightly higher rate of degradation in the first year, and somewhat less output in high heat. Our summers are hot, so this is worth knowing, but it is not a reason to avoid PERC.

TOPCon: the newer standard

TOPCon stands for Tunnel Oxide Passivated Contact. It is usually made on what is called an N-type silicon wafer, whereas most PERC panels use P-type wafers. You do not need to remember the terms. What matters is the result: TOPCon cells convert a bit more of the sunlight into electricity and tend to lose less output as they age and as they heat up.

What it means for you:

• More output from the same roof. If your terrace is small, higher efficiency means more kW in the space you have.
• Better in heat. Panels lose some output as they get hotter. TOPCon generally loses less, which suits our climate.
• Slower ageing. N-type cells usually show lower first-year loss.

TOPCon panels usually cost a little more per watt than mono PERC, though the gap has narrowed as manufacturers have shifted production. For a roof where space is tight, or where you want to squeeze the most out of each square metre, TOPCon is often worth it.

Mono PERC vs TOPCon: how to choose

This is one of the most common questions we hear. Here is a practical way to decide.

Choose mono PERC if:

• you have plenty of unshaded roof space;
• your budget is the main constraint;
• you are buying from a manufacturer you trust and the price difference is meaningful.

Choose TOPCon if:

• your roof space is limited and you want maximum output from it;
• the price difference is small;
• you want the slightly better heat performance and slower ageing.

Either way, the manufacturer and the installation matter more than the cell type. A TOPCon panel from an unknown brand, installed on a weak structure with cheap connectors, will perform worse over 25 years than a good mono PERC panel installed properly.

Half-cut panels: not a different cell, a different layout

"Half-cut" describes how the cells are arranged, not what they are made of. A half-cut panel uses cells sliced in half, wired so that each half of the panel works more independently. You will see half-cut versions of both mono PERC and TOPCon panels.

Why it helps:

• Less power lost inside the panel. Smaller cells carry less current, so less energy is lost as heat in the wiring inside the panel.
• Better with partial shade. If part of the panel is shaded, by a water tank, a parapet wall or a tree, the other half can keep producing more of its normal output.
• Cooler running. Lower internal losses mean less heat, which helps output in summer.

Most good panels sold today are half-cut. If a quote says "half-cut mono PERC" or "half-cut TOPCon", that is normal and good.

Bifacial panels: collecting light from both sides

A normal panel has an opaque back sheet, so only the front collects light. A bifacial panel has a transparent back, usually glass, so it can also collect light reflected from the surface underneath.

How much extra this gives depends almost entirely on the installation:

• On a raised structure over a light-coloured surface, bifacial panels can produce noticeably more, because sunlight bounces off the roof onto the back of the panel.
• Mounted flat and low on a dark roof, the back sees little light and the gain is small.
• On sheet roofs or flush mountings, there is almost no benefit.

Bifacial panels are also usually "glass-glass", meaning glass on both sides, which makes them sturdy and resistant to moisture.

When bifacial makes sense:

• elevated structures on flat terraces, especially with a white or reflective roof coating;
• ground-mounted systems over light soil or gravel;
• commercial systems where every extra unit adds up.

When it does not:

• low, flush mountings;
• small home systems where the extra cost is not recovered.

If someone recommends bifacial panels, ask how high the structure will be and what surface is underneath. Without height and reflection, you are paying for a back side that does very little.

Thin-film panels

Thin-film panels use very thin layers of material instead of silicon wafers. They are lighter and can be flexible, and they handle heat and diffuse light reasonably well. But they are less efficient, so they need more space for the same output.

On Indian rooftops, thin film is rare. You may see it on large commercial or utility projects, or for special uses such as curved surfaces. For a home terrace, crystalline silicon panels are almost always the better choice.

DCR and non-DCR panels

You will also hear "DCR" (Domestic Content Requirement). This is not a cell technology. It describes whether the solar cells were made in India.

It matters mainly because of the PM Surya Ghar subsidy rules, which call for domestically manufactured content. We explain the difference fully in our article on DCR vs non-DCR solar panels. One important point: the subsidy is paid only for systems installed by a vendor registered with your DISCOM. Origian Power is not a registered PM Surya Ghar vendor, so for our installations the subsidy rules do not apply, and the choice of panel comes down to performance, warranty and price.

What actually decides how much power you get

People focus on the panel type, but in our experience these things affect real-world output more:

Shading

Even partial shade on a few panels can pull down the output of a whole string. Water tanks, parapet walls, neighbouring buildings and trees all matter. A good site survey maps shade through the day before deciding where panels go.

Orientation and tilt

Panels facing roughly south, tilted at the right angle, produce more over the year. Our guide to solar panel tilt angle and orientation for Hyderabad and Anantapur explains the details. Our flat-roof structures use a 10 to 15 degree tilt.

Heat

Panels lose output as they heat up. Raised structures let air flow underneath and keep panels cooler. This is one reason we use elevated frames on flat roofs.

Dust

Dust and bird droppings block light. In dry months, panels that are not cleaned can lose a meaningful share of their output. See our solar panel cleaning guide.

Connections and cables

Poor connectors and undersized cables lose energy and can become fire risks. We use Stäubli-grade MC4 connectors and correctly sized cable throughout. This is invisible once installed, which is why it is easy to skimp on.

Wattage, efficiency and size: reading a panel spec

When you get a quote, you will see a panel described something like "540 Wp half-cut mono PERC" or "580 Wp TOPCon bifacial". Here is what the parts mean:

• Wp (watt-peak) is the panel's rated output under standard test conditions. A 540 Wp panel produces 540 watts in those conditions. Real output on your roof is usually lower and varies through the day.
• Efficiency tells you how much of the sunlight hitting the panel is turned into electricity. Higher efficiency means more output per square metre.
• Dimensions matter for fitting your roof. Higher-wattage panels are often physically larger.

So a 3 kW system might use about six panels of around 540 Wp, or a different number of higher-wattage panels. The total kW is what matters, not the panel count.

Our article on solar panel efficiency explains efficiency in more depth.

Warranty: the best quality signal you have

A panel's warranty tells you how confident the manufacturer is. Look for two separate warranties:

• Product warranty: covers defects in materials and workmanship. The panels we install carry 10 years.
• Performance warranty: guarantees the panel will still produce a stated share of its rated output after a number of years. The panels we install carry a 25-year performance warranty.

Ask whose warranty it is (the manufacturer's or the installer's), how you claim it, and whether the installer will handle the claim for you.

Brands: why the manufacturer matters more than the label

A "TOPCon" label from an unknown manufacturer is not automatically better than a mono PERC panel from an established one. Over 25 years, what matters is whether the manufacturer will still exist to honour the warranty, how consistent its quality control is, and how its panels perform in real Indian conditions.

The panels we install come from Renewsys, Adani, Waaree and Tata. We are not saying other brands are poor. We choose these because we can stand behind them for the life of the system.

Which panel is right for your roof?

Here is a simple guide based on the situations we see most.

A family home in Hyderabad with a good-sized open terrace. Half-cut mono PERC or TOPCon from an established brand. If the price difference is small, TOPCon for the better heat performance.

A home with a small terrace or lots of shade. Higher-efficiency TOPCon, half-cut, carefully placed to avoid shade. Ask about the shading assessment.

A raised structure over a terrace you want to use underneath. Consider bifacial, especially if the roof surface is light-coloured, but only if the extra cost is recovered.

A commercial or hospital roof. Efficiency and long-term reliability matter more. TOPCon, possibly bifacial on raised structures. See our guide to commercial rooftop solar.

A tight budget with plenty of space. A good mono PERC system gives excellent value.

Questions to ask your installer about panels

1. What is the exact panel make and model, and its wattage?
2. Is it mono PERC or TOPCon, and is it half-cut?
3. If bifacial, how high will the structure be and what is underneath?
4. What are the product and performance warranties, and who handles claims?
5. How will you avoid shading on the roof?
6. What tilt and orientation will you use?

How Origian chooses panels for you

We do not push one technology for every roof. During the site visit we look at your space, shading and electricity use, then recommend panels that fit. Our quotations list the exact equipment, the full price before any subsidy, and our warranty terms. We pair the panels with galvanised, wind-rated structures, proper earthing and quality connectors, because the best panel in the world underperforms on a poor installation.

If you are comparing options, book a free site survey or read our home solar cost guide first.

Myths about panel types we hear on site visits

"Black panels are always better." Most monocrystalline panels look dark, and many TOPCon panels look uniformly black, but colour alone tells you nothing about quality. Check the datasheet, the manufacturer and the warranty.

"More watts per panel means more power from my roof." Not exactly. A higher-wattage panel is usually physically larger. What matters is the total kW you can fit on your usable, unshaded roof, and how well that system is installed.

"Bifacial always gives 20–30% more." The extra output from a bifacial panel depends almost entirely on height and the reflectivity of the surface beneath. On a low, flush mounting over a dark roof, the gain can be very small.

"Imported panels are always better than Indian ones." Panel quality depends on the manufacturer, not the country. Several established Indian manufacturers produce high-quality modules, and for the PM Surya Ghar subsidy, domestic content is part of the rules.

Frequently asked questions

Which type of solar panel is best for home in India? For most Indian rooftops, monocrystalline panels (mono PERC or TOPCon) are the practical choice: efficient, widely available and well warrantied. TOPCon is newer and slightly more efficient. Bifacial panels help mainly on raised structures over light surfaces. Choose on efficiency, temperature coefficient, warranty and the manufacturer's track record, not on type alone.

Is TOPCon better than mono PERC solar panels? TOPCon solar panels are generally a little more efficient than mono PERC and tend to lose less output in heat, which helps in Telangana and Andhra Pradesh summers. Mono PERC remains proven and is often cheaper. On a roof with spare space the difference is small; on a tight roof, TOPCon's extra watts can matter.

Are bifacial solar panels worth it on a home roof? Bifacial solar panels collect reflected light on their rear side, but on a typical rooftop the real gain is smaller than brochure figures. They work best on raised structures over light-coloured surfaces with space between rows. On a dark, crowded roof, a good monofacial panel often gives similar results for less money.

What are half-cut solar panels? Half-cut solar panels use cells cut in two, which lowers the current in each cell and the resistive losses. The panel is wired as two halves, so shade on one part reduces output less than in a full-cell panel. Most modern monocrystalline panels, including mono PERC and TOPCon, now use half-cut cells.

Are polycrystalline solar panels still worth buying in India? Rarely, for rooftops. Polycrystalline solar panels are less efficient than monocrystalline ones, so you need more roof space for the same output, and most manufacturers have moved production to mono PERC and TOPCon. On a limited Indian rooftop, monocrystalline panels usually give more units per square metre for a similar overall cost.

Which solar panel brands does Origian install? Origian installs solar panels from Renewsys, Adani, Waaree and Tata, chosen to suit the system and budget. All carry a 10-year product warranty and a 25-year performance warranty. Your quotation names the exact brand and model, so you can check the datasheet and warranty terms before you sign anything.

How long do solar panels last? Solar panels typically last 25 years or more. Output falls slowly each year, and the 25-year performance warranty on the panels we install guarantees a minimum output over that period. Panels often keep producing beyond 25 years at reduced output, while inverters usually need replacing at least once during that time.