What are the different types of solar panels? Monocrystalline vs polycrystalline and thin-film – UK Times

With energy prices still prone to sudden swings, more UK households are looking at solar as a way to cut bills and lean less on the grid. But once you start comparing the best solar panels, the next question is surprisingly practical: what type should you actually fit on your roof?

In the UK, most domestic systems use one of three panel types: monocrystalline, polycrystalline, or thin-film. All turn sunlight into electricity, but they differ in how efficiently they do it, how long they tend to last, and how much space they need to deliver a useful output. In other words, choosing the right technology sits right alongside deciding whether solar panels are worth it for your home in the first place.

What are the main types of solar panels?

Most domestic solar installations in the UK use silicon-based panels, either monocrystalline or polycrystalline. These dominate the market because they balance efficiency, durability and cost. Thin-film panels, which use different photovoltaic materials applied in very thin layers, are far less common on residential rooftops and are typically used in commercial or specialist settings.

Monocrystalline solar panels

Monocrystalline panels are now the default choice for most UK homes. They are made from a single, pure silicon crystal, allowing electricity to flow more efficiently through the panel. Visually, they are usually black with a uniform finish.

Modern monocrystalline panels typically achieve efficiency ratings of around 19-23 per cent, meaning they produce more electricity per square metre than other panel types. This makes them particularly well-suited to UK housing, where roof space is often limited and typical systems are sized at around 3-4kWp.

Installers generally point out that while monocrystalline panels cost more upfront, the gap has narrowed in recent years. In practice, the higher output often means fewer panels are needed, which can offset the initial price difference. Lifespans are long, with performance warranties commonly lasting 25 years or more.

As one installer we spoke to explained, efficiency tends to matter more than panel price in the UK, because most homes are restricted by roof space rather than budget.

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Polycrystalline solar panels

Polycrystalline panels are made by melting together multiple silicon crystals. This process is simpler, but it results in slightly lower efficiency. These panels usually have a blue, speckled appearance.

Typical efficiency ratings for polycrystalline panels sit at around 15 to 18 per cent. As a result, more panels and more roof space are needed to achieve the same output as a monocrystalline solar panel system. For homes with larger roofs, this may not be an issue, but it can be a limiting factor for many UK properties.

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Polycrystalline panels were once popular because they were noticeably cheaper, but installers say that price differences have narrowed to the point where many households now opt for monocrystalline instead. Lifespans are still strong, with warranties often covering 20 to 25 years, but lower output means long-term returns can be reduced.

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Thin-film solar panels

Thin-film solar panels are produced by applying thin layers of photovoltaic material to surfaces such as glass or metal. They are lighter and more flexible than silicon panels and can be used on curved or non-standard roofs.

However, thin-film panels typically achieve efficiency ratings of just 10-13 per cent, making them far less suitable for UK homes. In a climate where sunlight is limited and roof space is at a premium, this low efficiency means significantly more surface area is required to generate useful amounts of electricity.

Thin-film panels also tend to have shorter lifespans, with warranties often ranging from 10 to 20 years. While the panels themselves can be cheaper, installers note that the cost per unit of electricity generated is usually higher.

For these reasons, thin-film panels are rarely recommended for domestic rooftops in the UK and are more commonly used in commercial or specialist applications.

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Types of solar panels compared

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Which type of solar panel is best for UK homes?

For most households, monocrystalline solar panels are the best option. Their higher efficiency allows homeowners to maximise electricity generation from limited roof space, which is a key consideration in UK housing. They also tend to perform more consistently in low-light conditions than older panel technologies.

Polycrystalline panels can still be a viable choice for homes with larger roofs or tighter budgets, but they are becoming less common in new installations. Thin-film panels are generally unsuitable for domestic use and are best reserved for specialist projects.

Installers consistently emphasise that panel type is only one part of the decision. System design, inverter quality, installation standards and warranties all play a major role in determining whether solar panels are a worthwhile investment. Comparing full-system quotes, rather than focusing on panels alone, is the most reliable way to choose the right setup for your home.

Other solar panel “types” you’ll see (and what they actually mean)

Beyond monocrystalline, polycrystalline and thin-film, you’ll often see extra labels in installer quotes and product spec sheets. These don’t usually describe a completely different type of solar panel. Instead, they’re typically a thin-film material, a panel design feature, or a cell technology used inside a monocrystalline panel.

Thin-film subtypes: different materials, same category

Thin-film panels are sometimes broken down by the material used, such as amorphous silicon (a-Si), cadmium telluride (CdTe), or CIGS. These can affect efficiency and cost, but they’re still all “thin-film,” and thin-film remains a niche choice for most UK homes compared with monocrystalline solar panels.

“Bifacial” panels: a design feature, not a new panel type

Bifacial panels can generate electricity from both the front and the rear, with the idea being that any light being reflected off the roof underneath the panel can also be converted into electricity. In the right setup (for example, mounted above a light-coloured surface that reflects sunlight), they can produce more energy than a standard solar panel. The key point is that bifacial is usually an add-on design to monocrystalline panels, not a separate technology category.

Half-cut, shingled and “black frame”: build and aesthetics

You may see solar panels described as half-cut or shingled. These refer to how the cells are arranged and wired, which can improve performance in partial shade and reduce electrical losses. Likewise, “all-black” or “black frame” is mainly an appearance choice. Again, these are typically variations of monocrystalline panels, not distinct solar panel types.

PERC, TOPCon, HJT, IBC: cell technology labels

These acronyms describe how the solar cells are engineered. They can affect real-world performance (especially in lower light), but they’re best thought of as generations of monocrystalline tech, rather than a fourth or fifth solar panel type. If you’re comparing quotes, they’re useful as a sign that you’re looking at newer designs, but efficiency, warranty, and cost-per-watt still matter more than the acronym alone.

Solar tiles and BIPV: solar that replaces your roof covering

Some solar products are designed to sit flush with the roof and, in some cases, replace part of the roof covering. You’ll see these described as solar tiles or building-integrated photovoltaics (BIPV). They can be a neat solution where appearance is a priority, but they’re typically more expensive and more involved to install than standard roof-mounted panels.

Solar thermal: not the same as solar PV

Finally, it’s worth separating solar PV (which generates electricity) from solar thermal systems, which use roof-mounted collectors to heat water. Solar thermal is useful in the right home, but it isn’t a type of electricity-generating solar panel.