Types of solar panels

Solar panels are one of the most popular types of green energy technology in the UK, with nearly 1.5 million solar panel installations made as of February 2024.¹ With costs falling and several grants available to homeowners, we'll likely see many more solar panels adorning homes over the coming years.

If you’re deciding which solar panels to install on your rooftop, you’ll have several options to choose from. Each has its own characteristics, and some will be more suitable than others for your specific circumstances.

In this article, we’ll compare the efficiency, cost and other important features of the different types of solar panels available to homeowners.  

To learn how solar panels work and how to get them installed, read Solar Panels: The Snugg Energy 2024 Guide.

Types of solar panels

Main types of residential solar panels

Three main types of solar panels are commonly used for home installations:

• ‍Monocrystalline solar panels: Made from single-crystal silicon, these are one of the most efficient and popular types of home solar panel. They have a sleek black appearance. ‍
• Polycrystalline solar panels: Made from multiple silicon crystals melted together, these panels are a popular affordable choice for homeowners. They have a blue, speckled appearance. ‍
• Thin-film solar panels: Made by depositing one or more thin layers of photovoltaic material onto glass or plastic, these are a lightweight choice used more commonly in commercial or portable settings such as caravans and boats. They’re also suitable for unconventionally shaped roofs. They usually have a dark blue or black appearance.

Monocrystalline vs polycrystalline vs thin-film solar panels

Each type of solar panel has its pros and cons.

Emerging solar panel technologies

The solar industry is continuously evolving, with new more efficient and cost-effective technologies being developed in research labs around the world.

Some of the most promising emerging technologies include:

• ‍Perovskite solar cells: Perovskite solar cells have shown potential for high efficiency over 28% by layering perovskite crystals with silicon in a tandem cell design. Companies like Oxford PV plan to commercialise this low-cost, high-efficiency technology soon.² ‍
• Bifacial solar panels: Bifacial panels can generate electricity from both front and rear sides by capturing reflected light, boosting output by up to 30% compared to standard mono-facial designs. The latest bifacial monocrystalline panels exceed 22% efficiency.³ ‍
• Transparent solar panels: Transparent photovoltaic materials allow solar panels to be integrated into windows, skylights and other surfaces while allowing light transmission. Technologies like organic PV and quantum dots enable buildings to generate power without compromising aesthetics.⁴

PERC solar panels vs standard panels

While standard solar panels are good, affordable all-rounders, newer Passivated Emitter and Rear Cell (PERC) technology improves the standard design by adding a passivation layer to the rear of the cell. This layer reflects unabsorbed light back through the cell, increasing light absorption and boosting efficiency.

Efficiency and performance

Which type of solar panel is most efficient?  

Currently, monocrystalline solar panels are the most efficient type of solar panels available for residential use. But emerging technologies are pushing efficiency even higher.

• ‍Monocrystalline panels: 18-24% efficiency
  • The highest efficiency monocrystalline panels from companies like SunPower and LG can now reach up to 24% efficiency. ‍
• PERC (Passivated Emitter Rear Cell) panels: 20-24% efficiency
  • PERC technology increases efficiency by reducing electron recombination. The most efficient PERC monocrystalline panels match the 24% range. ‍
• Polycrystalline panels: 16-20% efficiency
  • Polycrystalline efficiency has improved to the 16-20% range for the most premium models. ‍
• Thin-film panels: 10-18% efficiency
  • Thin-film efficiency ranges widely, with cadmium telluride achieving around 16-18% and amorphous silicon achieving around 10-13%. ‍
• Emerging perovskite-silicon tandem cells: Up to 28% efficiency
  • Perovskite crystals layered with silicon have achieved over 28% efficiency in lab tests, which is a significant step up from current commercial panels.

Do certain types of panels perform better in certain conditions?  

Yes, different panel types can perform better in various conditions:

• ‍High temperatures: Thin-film panels generally perform better in hot climates since they have a lower temperature coefficient (they lose less efficiency as the temperature increases). ‍
• Low-light conditions: Monocrystalline panels (especially those using PERC technology) typically perform better in low-light conditions like cloudy days or early morning/late afternoon. ‍
• Limited space: Higher efficiency panels like monocrystalline or PERC are better suited for installations with limited roof space since they produce more power per square foot. ‍
• Weight constraints: Thin-film panels are lighter and more flexible than other types, making them suitable for installations where weight is an issue, like caravans and boats.

How does temperature affect the performance of different panel types?

The temperature coefficients provided by manufacturers show how much the panel’s power output will decrease for every degree above 25C. So, a -0.4%/C coefficient means a 4% drop in power for every 10C increase.

All solar panels lose some efficiency as temperatures increase, but the exact amount varies by panel type:

• ‍Monocrystalline panels: These generally have a temperature coefficient of -0.3% to -0.5% per degree above 25C. ‍
• Polycrystalline panels: These typically have a slightly higher temperature coefficient, around -0.35% to -0.5% per degree above 25C. ‍
• Thin-film panels: These usually have the best temperature coefficient of around -0.2% to -0.3% per degree above 25C.

Although thin-film panels have the lowest temperature coefficient, this wouldn’t be a major concern in the UK due to the cooler climate. Mono- and polycrystalline panels are equally suitable from a temperature standpoint.

Which type of panel performs best in low-light conditions?

• ‍Monocrystalline panels - especially those using PERC technology - generally perform best in low-light conditions. ‍
• Polycrystalline panels also perform well in low light, despite being less efficient than monocrystalline panels. ‍
• Thin-film panels, particularly those made with amorphous silicon, can also perform relatively well in low-light conditions. But their overall lower efficiency means they could still produce less power than high-efficiency monocrystalline panels.

Cost considerations  

One of the biggest considerations when choosing solar panels is the cost. You’ll need to pay for the installation cost too to get them fitted, but here we’ll compare the cost of the solar panels themselves.

What are the price differences between various types of solar panels?  

The following costs are estimates. The actual cost will vary depending on the brand and size of panel.

• ‍Monocrystalline panels: £250 - £350 per m2 ‍
• Polycrystalline panels: £200 - £300 per m2 ‍
• Thin-film panels: £150 - £200 per m2

Which type of panel offers the best value for money?  

The following costs are estimates. The actual cost will vary depending on the brand and size of panel.

• ‍Monocrystalline panels: £1,000 - £1,500 per kW ‍
• Polycrystalline panels: £800 - £1,200 per kW ‍
• Thin-film panels: £600 - £800 per kW

There are other benefits to consider when choosing more efficient solar panels:

• They produce more energy per square meter, requiring less roof space for the same system size.
• Higher energy yields can provide a faster return on investment despite the higher upfront cost.
• More efficient panels perform better in less-ideal conditions like high temperatures or when within a shaded area.

Are more efficient panels always more expensive?  

More efficient solar panels tend to cost more, but they can potentially provide better value and faster payback times in the long run.

For example, let’s compare the following two panels:

• A high efficiency 300W panel costing £300
• A standard 250W panel costing £200

Over 25 years:

• The 300W panel could generate 18,750 kWh
• The 250W panel could generate 15,625 kWh

At £0.25/kWh, the high-efficiency panel would produce an extra £781.25 worth of electricity over its lifetime - much greater than its first £100 higher cost.

How do the long-term costs compare between different panel types?

As we’ve seen, the long-term cost savings can outweigh the initial up-front cost. But how do the different panels compare?

• ‍Monocrystalline panels: These have the highest upfront costs but offer the best long-term value thanks to their high efficiency (15-23%) and long lifespan (25-40 years). ‍
• Polycrystalline panels: These present a good middle ground, with moderate upfront costs, decent efficiency (13-16%) and good lifespan (20-35 years). ‍
• Thin-film panels: These have the lowest upfront costs but their moderate efficiency (7-18%) and shorter lifespan (10-20 years) results in a lower long-term payback compared to other types of panel.

Installation considerations  

Solar panels should be installed by experts, so you shouldn’t need to consider the complexity of installation yourself. However, more complex installations can take more time, which you may wish to factor in when choosing the type of panels for your home.

Are certain types of panels easier to install than others?  

There isn’t a significant difference between installing crystal silicon panels, but thin-film panels are typically much more versatile and simpler to install.

• ‍Monocrystalline panels: Being the most efficient type of residential solar panel, fewer panels often need to be installed, simplifying and speeding up the installation process. ‍
• Polycrystalline panels: Being less efficient than monocrystalline panels, it may be that more of these panels would need to be installed on your roof to meet your needs. This could make it a little more complex  ‍
• Thin-film panels: Being the most lightweight and flexible type of panel, thin-film panels are very easy to install. Their light weight makes them easy to handle, and their flexibility means they’ll be suitable for almost any shaped roof. Some can be simply stuck to the roof’s surface, reducing the need for any mounts to be fitted.

Do different panel types require different mounting systems?  

Solar panels can be installed in various ways to match your home’s needs. For example, if you live in an area with high winds, you might consider a fully railed system for maximum structural support. And if your home has a modern and sleek look, you might consider a rail-less system to help your panels blend in.

• ‍Monocrystalline and polycrystalline panels: These panels both need to be mounted on the roof (or ground) using a rigid racking system. This includes fully railed systems, shared rail systems and rail-less systems. ‍
• Thin-film panels: These panels can be mounted using rail systems, but they can also be fitted to roofs directly using adhesives. Some thin-film panels come with a peel-and-stick backing, further simplifying the installation process.

Can all panel types be installed on any roof type?

Although most solar panels can be mounted on most roofs, there are some limiting factors.

• ‍Roof material: Wooden or thatched roofs aren’t suitable for mounting electric solar panels because it can pose a fire hazard and may not be able to support the weight of the panels. ‍
• Roof pitch: Roofs that are particularly steep (over 45 degrees) or shallow (under 20 degrees) can pose challenges when mounting solar panels, although it’s not impossible. But steep or shallow roofs aren’t best for solar panels to work efficiently - they’d be ideally positioned at 30 to 35 degrees. ‍
• Roof shape: Depending on the shape of your roof, rigid monocrystalline and polycrystalline panels may not be suitable. Multiple angles, chimneys or other space-limiting factors can pose challenges mounting solar panels. They may need a less efficient panel layout or might require thin-film panels to be used.

Durability and lifespan  

When choosing the right solar panel for your needs, you’ll want to consider how they’ll cope with weather conditions and how long they’ll last before needing to be replaced.

Which type of solar panel has the longest lifespan?  

A solar panel’s lifespan is affected by the quality of materials used, how it’s installed, local weather conditions and how well it’s maintained.

On average, you can expect them to last around...

• ‍Monocrystalline panels: 25-40 years
  • These typically have the longest lifespan due to their high-quality, single-crystal silicon construction and robust manufacturing process. ‍
• Polycrystalline panels: 20-35 years
  • While slightly less durable than monocrystalline, these still offer a good lifespan for most homeowners. ‍
• Thin-film panels: 10-20 years
  • These generally have the shortest lifespan among the three common types of panels. But they’re most suitable for situations where flexibility or low cost is most important.

How do different panel types compare in terms of degradation rates?  

All solar panels generate a little less energy over time due to the negative effects of UV exposure, thermal cycling (the repeated heating and cooling of the panel over time), humidity and microcracks occurring in the solar cells. This process is called degradation, and the speed at which it occurs is referred to as the degradation rate.

Each type of solar panel degrades at a different rate due to its unique structure.

• ‍Monocrystalline panels: Approx 0.3% annual degradation rate. They’d produce around 92.5% of their original output after 25 years. ‍
• Polycrystalline panels: Approx 0.5% annual degradation rate. They’d produce around 87.5% of their original output after 25 years. ‍
• Thin-film panels: Approx 0.8-1% annual degradation rate. They’d produce around 75-80% of their original output after 25 years.

Are certain types of panels more resistant to weather damage?  

The materials and construction method affect a solar panel’s ability to withstand weather damage. Here’s a comparison...

• ‍Monocrystalline panels: Very high weather resistance
  • Its single, pure silicon crystal construction has few internal defects and boundaries which make it more resistant to temperature fluctuations and physical impacts. ‍
• Polycrystalline panels: High weather resistance
  • Its construction, made by melting multiple silicon fragments together, results in more internal boundaries which are more susceptible to thermal cycling (repeated heating and cooling) and physical impacts. ‍
• Thin-film panels: Medium weather resistance
  • Weather resistance will depend on the type of technology used (amorphous silicon, cadmium telluride, or copper indium gallium selenide). But the physically thinner and flexible nature of its construction can make it more vulnerable to physical impacts like hailstones.

Do some panel types require more maintenance than others?

Solar panels don’t need a lot of maintenance, regardless of type. But there are some differences between them...

• ‍Monocrystalline panels: These extremely durable panels don’t need much maintenance at all. Their smooth surface allows leaves and dust to slide off during wind or rain, and its construction materials don’t degrade too quickly over time. Only during thick snow might you want to wipe them clean, if you have safe access to them. ‍
• Polycrystalline panels: These panels collect dirt a little more easily than monocrystalline panels due to their construction methods. They also degrade at a faster rate in hot climates, requiring more frequent performance checks. ‍
• Thin-film panels: These thinner panels are more susceptible to physical damage and should be checked regularly. They also degrade faster than other panels, requiring more performance checks. However, they still shouldn’t need a lot of maintenance in ideal conditions.

You can minimise maintenance by installing your panels at a steeper angle (so debris can wash away more easily) and away from nearby trees that may drop leaves.

Aesthetic considerations  

Usually, solar panels are installed on rooftops which are highly visible. So, it’s important to consider the look of the panels when choosing between them.

Which type of solar panel looks the most attractive on a roof?  

The type of solar panel you prefer the look of is subjective, but here's a quick overview of what to consider when choosing:

• ‍Monocrystalline panels: Modern homes can benefit from these sleek, black panels. They can be installed with black frames too, for a more seamless look. ‍
• Polycrystalline panels: The blue tint of these panels can complement older homes, where black modern-looking monocrystalline panels might contrast too much with the age and design of the home. ‍
• Thin-film panels: These panels aren’t ideal for rooftops, unless you have an unconventionally shaped roof or live in a particularly shaded area. Their plain, flat appearance can look very modern and may not suit older buildings too well. And due to their inefficiency, you’ll need to use more roof space to install a larger array of panels compared to other types.

More recently, solar panels have been incorporated into individual roof tiles to mimic the natural look of a roof. They can even be supplied in various natural tile colours. But while solar roof tiles are more discreet than conventional panels, they're much more expensive.

Are there colour options available for different panel types?  

It is possible to buy solar panels in colours other than their usual black or blue. The effect is achieved by dying or coating the panel with a thin layer of coloured film, and it can be a good way of blending in the panels with the roof it’s installed on. But there are some downsides to bear in mind.

First, coloured solar panels (such as white, red, grey and green) tend to be less efficient than natural black/blue coloured panels. This is due to the colour dye/coating reflecting more of the sunlight, which can reduce efficiency by up to 45%.⁵

Second, coloured solar panels tend to be more expensive than naturally-coloured panels. This is because they’re less common and produced by specialist manufacturers in the UK.

At this moment, coloured solar panels aren’t widely available or affordable in the UK. But as technology advances, a wider range of colours and efficiencies will be made.

Do some types of panel blend in better with certain roof styles?

Some types of solar panel do blend in with certain roof styles.

• ‍Monocrystalline panels: These panels tend to compliment modern and minimalist homes due to their sleek, uniform black appearance. They look most striking on grey and black roofs. ‍
• Polycrystalline panels: These panels tend to compliment traditional and coastal-style homes due to their blue, speckled appearance. They work particularly well with light grey and blue-tinted roofs. ‍
• Thin-film panels: These panels tend to compliment contemporary style homes due to their low profile and flexible design. They can also be incorporated into solar tiles to look just like the real thing, making them an option for traditionally styled modern homes.

Space requirements  

Solar panels come in various sizes, and their efficiency impacts the number of panels you’ll need.

Which type of panel is best for homes with limited roof space?  

If you have limited roof space, you may want to consider monocrystalline solar panels. These have around 15-23% efficiency, making them one of the most efficient types of residential panel.

Thanks to their high energy efficiency, they don’t need as much roof space as other types of panels.

How do space requirements differ between panel types?  

Space requirements vary depending on the type of solar panel you choose.

• ‍Monocrystalline panels: With around 19% efficiency, a 4kW system would need around 14 panels. This would require roughly 22 square metres of roof space. ‍
• Polycrystalline panels: With around 15% efficiency, a 4kW system would need around 17 panels. This would require roughly 27 square metres of roof space. ‍
• Thin-film panels: With around 12% efficiency, a 4kW system would need around 21 panels. This would require roughly 33 square metres of roof space.

Bear in mind that these examples are rough estimates. The actual numbers may differ slightly due to factors such as how the panels are fitted to the roof, the gaps between panels, any efficiency losses within the power conversion system, etc.

Can different panel types be mixed on the same roof to maximize space?

Although it is possible to mix different types of solar panels (e.g. monocrystalline and polycrystalline) there are several reasons why you may wish to avoid doing so.

• ‍Compatibility: Different panels have varying voltages and electrical characteristics and mixing them could lead to inefficiencies or even damage. ‍
• Complexity: Mixing panel types will complicate the installation process. Different mounting systems, wiring configurations and a more complex system design would be needed. This could increase both the installation time and cost. ‍
• Aesthetics: Each panel type has a different appearance. Mixing black monocrystalline panels and blue polycrystalline panels in a single array might look strange and put people off.

Environmental impact  

Solar panels are a great way to reduce grid energy usage and produce your own green energy. And in the long run, they more than make up for the initial energy used in their production.⁶ But you may want to factor in the environmental impact of making and disposing of the panels when choosing which type of panel to install.

Which type of solar panel has the lowest carbon footprint in production?  

From smelting raw silicon from sand to attaching a metal supporting frame around the panel, the manufacture of solar panels uses a lot of energy. But some types of panels have a higher carbon footprint than others.

• ‍Monocrystalline and polycrystalline panels: The production of these panels emits around 50-60 grams of CO2 equivalent per kilowatt hour.⁷ ‍
• Thin-film panels: The production of these panels emits around 12-20 grams of CO2 equivalent per kilowatt hour.

Are there any environmental concerns with specific panel types?  

All solar panels are currently made from materials that are mined, such as silicon and cadmium. Environmental issues can arise if this isn’t done sustainably.

The manufacture of silicon panels also generates waste that requires treatment with potentially harmful chemicals such as hydrochloric acid, which can potentially harm the environment.

Some types of thin-film panels, such as Cadmium Telluride (CdTe) use toxic metals such as cadmium which can potentially be bad for the environment if not properly managed.

How recyclable are different types of solar panels?

The process of recycling solar panels varies depending on the panel type. In all cases, by far the most abundant material is glass (76% of silicon-based panels and 89% of thin-film panels), which can be easily recycled.⁸

• ‍Monocrystalline and polycrystalline panels: These panels are highly recyclable, with up to 95% of their materials recoverable. 100% of their aluminium frames can be recycled, while around 85% of their silicon can be recycled.⁹ The plastic components (such as the backsheet) are more challenging to recycle, however. ‍
• Thin-film panels: These panels are also highly recyclable, with around 95% of their semiconductor materials recyclable. However, some types of thin-film panels contain potentially hazardous materials like cadmium which are more difficult and expensive to recycle.

When it comes to recycling your own solar panels, you’ll need to contact the solar panel manufacturer. In the UK, they’re required by law to collect them and take them to be recycled.