Types of Solar Panels Explained
Monocrystalline, polycrystalline, thin film, bifacial — which type of solar panel is right for your home? Here's how every technology compares for UK installations in 2026.
Quick Answer
The most common solar panel type installed on UK homes in 2026 is monocrystalline N-type TOPCon. These panels offer 21–24.6% efficiency, 25–30 year warranties, and excellent low-light performance. Polycrystalline panels are largely discontinued for residential use, while thin film and bifacial panels serve niche applications like commercial roofs and ground-mount systems.
What are the different types of solar panels?
Solar panels are categorised by the type of photovoltaic cell they use. The three main categories are monocrystalline (single-crystal silicon), polycrystalline (multi-crystal silicon), and thin film (a thin layer of semiconductor material deposited on glass or flexible substrate). Within monocrystalline, there are further sub-types based on cell architecture: PERC, TOPCon, HJT, and IBC.
There are also bifacial panels, which can generate electricity from both sides. Bifacial is not a cell type in itself — most bifacial panels use monocrystalline N-type cells — but the design is distinct enough to warrant its own category.
Monocrystalline
Single-crystal silicon. The dominant technology for UK residential solar. Includes N-type TOPCon, HJT, P-type PERC, and IBC sub-types. Black or dark grey appearance.
Polycrystalline
Multi-crystal silicon. Recognisable by their blue speckled appearance. Lower efficiency and largely discontinued for new UK residential installations.
Thin Film
Thin semiconductor layer (CdTe or CIGS) on glass or flexible substrate. Lightweight and flexible, but lower efficiency. Used for commercial and unusual surfaces.
Bifacial
Generates from both front and rear sides. Typically monocrystalline N-type cells with a transparent backsheet. Best for ground-mount and elevated installations.
IBC (Back Contact)
All electrical contacts on the rear surface for a clean front appearance. Premium efficiency (22–24.6%). SunPower Maxeon is the leading IBC brand.
HJT (Heterojunction)
Combines crystalline silicon with amorphous thin film layers. Very low degradation and excellent temperature performance. Newer, premium technology.
Solar panel types compared
This table compares every solar panel type you are likely to encounter when getting quotes from UK installers. The “UK residential use” column reflects how commonly each type is installed on homes in 2026.
| Panel Type | Efficiency | Appearance | Warranty | Cost | UK Residential Use |
|---|---|---|---|---|---|
| Mono N-type TOPCon | 21–24.6% | Black / dark grey | 25–30 years | £0.25–£0.35/W | Most common (2026) |
| Mono N-type HJT | 22–26% | Black | 25–30 years | £0.35–£0.50/W | Emerging, premium |
| Mono P-type PERC | 19–21% | Blue-black | 12–25 years | £0.20–£0.28/W | Being phased out |
| Polycrystalline | 15–18% | Blue speckled | 10–25 years | £0.15–£0.22/W | Largely discontinued |
| Thin Film (CdTe/CIGS) | 10–13% | Uniform black | 10–25 years | £0.10–£0.20/W | Commercial / niche |
| Bifacial | 20–24%+ | Transparent back | 25–30 years | £0.30–£0.45/W | Ground mount / elevated |
| IBC (Back Contact) | 22–24.6% | Clean black front | 25–40 years | £0.45–£0.65/W | Premium / limited space |
Cost per watt is the panel cost only (excluding installation). Installed system costs are higher. All efficiency figures are based on manufacturer datasheets under standard test conditions (STC).
Monocrystalline solar panels (N-type TOPCon) — the standard choice
Monocrystalline panels use cells cut from a single crystal of silicon. This uniform crystal structure gives them higher efficiency than polycrystalline panels. In 2026, the vast majority of monocrystalline panels sold in the UK use N-type TOPCon cell technology, which has replaced older P-type PERC as the industry standard.
Leading brands include Jinko Solar (Tiger Neo), JA Solar (DeepBlue 4.0), Trina Solar (Vertex S+), and Canadian Solar (TOPHiKu6). These panels typically deliver 440–460W per panel with 21–24.6% efficiency, and come with 25–30 year warranties.
Pros
- Highest efficiency (21–24.6%) — more power per m²
- Excellent low-light and overcast performance (ideal for UK climate)
- Lowest degradation rate (0.3–0.4% per year)
- Long warranties (25–30 years product, 25–30 years performance)
- Sleek black or dark grey appearance
- Widely available from all UK installers
Cons
- Higher panel cost than polycrystalline (though gap has narrowed significantly)
- Standard rigid design — not suitable for curved surfaces
- All mainstream options look similar — limited aesthetic variety
Bottom line: N-type TOPCon monocrystalline is what you should expect from any reputable UK installer in 2026. If your quote includes P-type PERC panels instead, ask why — it may be discounted older stock, which can be acceptable if the price reflects it.
Polycrystalline solar panels — why they're obsolete for UK homes
Polycrystalline (or multi-crystalline) panels use cells made from multiple silicon crystals melted together. They were once the most popular residential choice due to their lower manufacturing cost. You can recognise them by their distinctive blue, speckled appearance.
However, the price gap between monocrystalline and polycrystalline has narrowed to the point where poly panels no longer make economic sense. All major Tier 1 manufacturers have discontinued residential polycrystalline lines in favour of N-type monocrystalline technology. If an installer offers you polycrystalline panels in 2026, this is a red flag.
Pros
- Lowest upfront panel cost
- Proven technology with decades of field data
- Still functional — existing installations work fine
Cons
- Lower efficiency (15–18%) — need more roof space for same output
- Poorer low-light performance (problematic for UK weather)
- Higher degradation rate than N-type mono
- Discontinued by major manufacturers for residential use
- Shorter warranties on remaining stock
- Blue speckled look is less aesthetically appealing on most roofs
Bottom line: Do not choose polycrystalline panels for a new UK residential installation. The small cost saving is not worth the lower output, shorter lifespan, and limited warranty. If you already have poly panels on your roof, they will continue working — expect around 80–85% of original output after 25 years.
Thin film solar panels — niche use cases
Thin film panels use a very thin layer of photovoltaic material — typically cadmium telluride (CdTe) or copper indium gallium selenide (CIGS) — deposited onto glass, plastic, or metal. They are much lighter and can be manufactured on flexible substrates, making them suitable for applications where traditional rigid panels cannot be used.
In the UK, thin film panels are almost never used on standard residential rooftops. Their lower efficiency (10–13%) means you need roughly twice the roof area to match monocrystalline output. They are primarily used for large commercial roofs, building-integrated photovoltaics (BIPV), and unusual or curved surfaces.
Pros
- Lightweight — less structural load on roofs
- Flexible options available for curved surfaces
- Better performance in very high temperatures
- Uniform black appearance (aesthetically clean)
- Lowest cost per watt for the panel itself
- Less affected by partial shading than crystalline
Cons
- Much lower efficiency (10–13%) — needs double the roof space
- Faster degradation than crystalline silicon panels
- Fewer installer options — most UK residential installers do not stock them
- CdTe contains cadmium (toxic) — disposal considerations
- Shorter warranties on average
Bottom line: Thin film only makes sense if you have a very large commercial roof, a curved or lightweight structure that cannot support rigid panels, or a building-integrated application. For standard UK homes, monocrystalline is the better choice in every measurable category.
Bifacial solar panels — when they make sense
Bifacial panels generate electricity from both the front and the rear side. The rear side captures light reflected off the ground or mounting surface (albedo). Most bifacial panels use monocrystalline N-type cells with a transparent glass or clear backsheet on the rear.
The extra rear-side generation typically adds 5–30% additional output, depending on the mounting height, ground surface (white gravel or concrete reflects more than grass), and tilt angle. This makes bifacial panels ideal for ground-mount systems and elevated structures like carports and pergolas.
Pros
- 5–30% extra generation from rear side
- Higher energy yield per panel over lifetime
- Glass-glass construction is more durable and weather-resistant
- Lower degradation — glass rear protects cells better than polymer backsheet
- Ideal for ground mount, carports, pergolas, and tracker systems
Cons
- Higher cost per panel (10–20% premium over standard mono)
- Limited rear-side benefit on flush roof mounts (dark tiles reflect little light)
- Heavier due to glass-glass construction
- Requires careful mounting design to maximise rear exposure
- Overkill for most standard residential roof installations
Bottom line: Bifacial panels are excellent for ground-mount systems, solar farms, carports, and any installation where the rear side is elevated and exposed to reflected light. For a standard flush-mounted residential roof, the rear side gets almost no reflected light, so the extra cost is not justified.
Which type of solar panel should you choose?
For most UK homeowners, the decision is straightforward. Here is our recommendation by situation:
Most UK homes: N-type TOPCon monocrystalline
This is what the vast majority of UK installations use in 2026. Brands like Jinko Solar, JA Solar, Trina Solar, and Canadian Solar offer 440–460W panels with 21–24% efficiency and 25–30 year warranties. This is the default — if your installer is quoting something different, ask why.
Limited roof space: IBC / SunPower Maxeon
If you have a small roof and need to maximise every square metre, IBC panels like the SunPower Maxeon 7 (24.6% efficiency) generate the most power per panel. The premium cost (roughly 30–50% more) is justified when roof area is the constraint, not budget.
Ground-mount systems: consider bifacial
If you are installing a ground-mount array on a farm, large garden, or commercial site, bifacial panels can generate 5–30% extra output from the rear side. The additional cost is often recovered within 2–3 years via higher generation, especially over a light-coloured surface.
Curved or unusual surfaces: thin film
For barrel roofs, curved facades, lightweight structures that cannot support rigid panels, or building-integrated applications, flexible thin film panels may be the only viable option. Expect lower output and plan for more surface area.
Budget-conscious: P-type PERC at a discount
You can still find P-type PERC panels as older stock from some installers, often at a meaningful discount. These are perfectly acceptable if the price is right — just be aware of lower efficiency (19–21%), slightly higher degradation, and potentially shorter warranties compared to N-type.
N-type vs P-type: the key difference
The terms “N-type” and “P-type” refer to how the silicon wafer is doped (treated with impurities to create an electrical field). This is the most important technical distinction in solar panels today.
| Feature | N-type (TOPCon / HJT) | P-type (PERC) |
|---|---|---|
| Silicon Doping | Phosphorus-doped (excess electrons) | Boron-doped (electron holes) |
| Generation | Current standard (2026) | Previous generation (being phased out) |
| Efficiency | 21–26% | 19–21% |
| LID (Light Induced Degradation) | Minimal — no boron-oxygen defects | 1–3% loss in first year from boron-oxygen reaction |
| Low-Light Performance | Better (higher minority carrier lifetime) | Standard |
| Temperature Coefficient | –0.29 to –0.32%/°C | –0.34 to –0.38%/°C |
| Annual Degradation | 0.3–0.4%/year | 0.4–0.55%/year |
| Output After 25 Years | ~88–92% of original | ~82–87% of original |
In plain English: N-type silicon does not suffer from the boron-oxygen defect that causes P-type panels to lose 1–3% of their output in the first year (light-induced degradation, or LID). N-type panels also have better electron mobility, which means they convert more sunlight to electricity, especially in low-light conditions — a significant advantage in the UK's often overcast climate.
All major Tier 1 manufacturers have transitioned their mainstream residential panels from P-type PERC to N-type TOPCon. If you are offered a P-type panel, it is likely older stock. This can be fine if the price reflects it, but N-type should be the default for any new installation in 2026.
Frequently Asked Questions About Solar Panel Types
What is the most efficient type of solar panel?
IBC (Interdigitated Back Contact) panels like the SunPower Maxeon 7 achieve up to 24.6% efficiency. Among more widely available panels, N-type TOPCon monocrystalline panels from Jinko, JA Solar, and Trina reach 21\u201322.5%. HJT (heterojunction) panels can reach up to 26% in lab conditions, with commercial models at 22\u201324%.
What is the difference between monocrystalline and polycrystalline solar panels?
Monocrystalline panels use cells cut from a single silicon crystal, giving them higher efficiency (21\u201324.6%) and a uniform black appearance. Polycrystalline panels use multi-crystal silicon, resulting in lower efficiency (15\u201318%) and a blue speckled look. The cost gap has narrowed to the point where polycrystalline is no longer manufactured for residential use by major brands.
Are thin film solar panels any good?
Thin film panels are good for specific applications \u2014 large commercial roofs, lightweight structures, curved surfaces, and building-integrated designs. However, their lower efficiency (10\u201313%) means they need roughly twice the surface area of monocrystalline panels. They are not recommended for standard UK residential roofs.
What are bifacial solar panels and are they worth it?
Bifacial panels generate electricity from both sides, capturing reflected light from the ground or mounting surface on the rear. They can produce 5\u201330% extra output depending on installation height and ground reflectivity. They are worth it for ground-mount systems and carports, but not for standard flush-mounted rooftop installations where the rear side gets little reflected light.
Should I choose N-type or P-type solar panels?
N-type is the clear choice for any new installation in 2026. N-type TOPCon panels offer higher efficiency, lower degradation, better low-light performance, and no light-induced degradation (LID). P-type PERC is the previous generation and is being phased out. If offered P-type at a significant discount, it can still be acceptable, but N-type should be the default.
How long do different types of solar panels last?
Monocrystalline N-type panels last 25\u201330+ years and retain 88\u201392% of original output after 25 years. P-type PERC panels retain 82\u201387% after 25 years. Polycrystalline panels have similar longevity to P-type PERC. Thin film panels typically last 15\u201325 years with faster degradation. All types continue generating beyond their warranty period, just at reduced output.
What type of solar panel do most UK installers use?
The vast majority of UK MCS-certified installers use monocrystalline N-type TOPCon panels in 2026. The most common brands are Jinko Solar, JA Solar, Trina Solar, and Canadian Solar, typically in 440–460W panel sizes. Premium installers may also offer SunPower Maxeon IBC panels.
Can I mix different types of solar panels on one roof?
It is technically possible but not recommended. Mixing panel types means different electrical characteristics, which reduces system efficiency. Each panel type would need its own string or microinverters. A well-designed system uses identical panels throughout. If you are expanding an existing system, your installer may recommend a separate string with different panels rather than mixing them on the same string.
Related Guides
Sources
- Energy Saving Trust — Solar Panels — energysavingtrust.org.uk
- MCS — Microgeneration Certification Scheme — mcscertified.com
- NREL — Best Research-Cell Efficiency Chart — nrel.gov
- Jinko Solar — Tiger Neo N-type TOPCon Datasheet — jinkosolar.com
- SunPower Maxeon — Maxeon 7 IBC Panel — maxeon.com
- Solar Energy UK — Industry Data — solarenergyuk.org
Last updated: March 2026
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He fact-checks all content against official MCS and Ofgem data and maintains relationships with MCS-certified installers across the UK.
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