How Much Do Solar Panels Weigh?

On average, a standard solar PV panel in the UK weighs between 18kg and 25kg per panel. This means a typical residential system of 10–12 panels will add around 200–300kg of additional weight to your roof.

Weight is an important consideration because your roof structure needs to be able to support the panels safely without compromising its integrity. 

But weight doesn’t just matter for safety, knowing how heavy solar panels are also helps in understanding installation costs, roof suitability, and long-term durability.

How Much Do Different Types of Solar Panels Weigh?

Not all solar panels are the same. Their weight varies depending on the size, wattage, frame material, and type (monocrystalline, polycrystalline, or thin-film).

As you can see, thin-film panels are lighter, but less efficient and require more space. For most UK homes, monocrystalline panels are preferred because they offer higher efficiency with manageable weight.

Choosing the right panel type also affects how many panels you can fit on your roof and the number of panels you will need, which is a key step in planning an efficient system. 

Can UK Roofs Handle the Weight of Solar Panels?

Most homes in the UK can support solar panels without issue. According to the Energy Saving Trust, a residential solar PV system adds around 10–12kg per square metre to your roof. Given that UK building standards already account for much higher loads such as snow and wind, this weight is generally well within safe limits.

However, older homes, particularly those built before the 1960s or properties with weaker roof structures may require reinforcement. In some cases, it’s worth considering whether roof repairs or a full roof replacement should be carried out before installing solar panels, as this can prevent future complications and ensure your investment lasts as long as possible. 

An MCS-accredited installer will carry out a structural survey before installation to confirm suitability.

Use our Solar Panel Calculator to find the ideal system size for your home and see how much you could save on electricity bills.

How Much Do Solar Panels Weigh on Commercial Buildings?

When it comes to commercial buildings in the UK, the weight of solar panels becomes a more significant factor than in residential systems due to the scale of installations. A typical commercial solar array may involve hundreds of panels, with each weighing between 23–30kg. This means the total system weight can reach several tonnes.

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  Warehouses and Factories: These buildings often have large, flat roofs that can support sizeable systems, but the ballast required to angle panels adds considerable extra weight. Structural assessments are essential.
  
  
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  Office Buildings: Many modern office blocks have reinforced concrete or steel structures, which can usually handle the load easily.
  
  
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  Older Commercial Properties: Roofs may need strengthening or specialist mounting solutions to distribute the weight safely.

All large-scale commercial solar installations must be designed by engineers who understand the building’s load-bearing capacity and compliance with UK building regulations. Proper planning ensures the added weight doesn’t compromise safety or long-term performance.

For businesses, solar remains a financially sound investment, but weight is one of the first structural considerations before moving ahead with installation.

How Does Weight Affect Solar Panel Installation?

Weight influences several practical aspects of installation:

Roof Type Compatibility

When it comes to roof type compatibility. Different roof materials respond differently to the load of solar panels.

Rubber roof

Installing solar panels on a rubber roof requires careful consideration of weight distribution. Rubber roofs are often found on extensions or commercial buildings, and while they are durable and weather-resistant, they typically need ballasted systems to avoid drilling into the membrane. 

Ballast increases the overall weight, so ensuring the roof’s structure can handle the additional load is essential.

Concrete roof

Installing solar panels on a concrete roof is usually straightforward, as concrete is one of the strongest and most load-bearing materials. The weight of solar panels (10–12kg per m²) is well within the capacity of most reinforced concrete roofs. 

However, the installation method often involves drilling into the surface or using ballasted systems, which can add weight but are rarely an issue with concrete.

Flat roof

Installing solar panels on a flat roof generally involves ballasted mounting systems to angle the panels correctly towards the sun. These ballasts add extra weight, sometimes up to 30% more, which must be factored into the roof’s load-bearing capacity. A structural survey is always carried out to confirm safety.

Slate roof

Installing solar panels on a slate roof can be more complex due to the fragile nature of the slates. While the overall weight of panels is manageable, the main risk is tile cracking during installation. Specialist fixings and experienced installers are required to distribute weight without damaging the roof.

Metal roof

Installing solar panels on a metal roof is often easier compared to other materials. Many metal roofs, especially standing seam types, allow panels to be clipped on without drilling, reducing installation time and avoiding added stress points. Metal roofs can usually bear the weight of solar panels well, but corrugated metal may need reinforced mounting to prevent flexing.

Tile roof

Installing solar panels on a tile roof is common across UK homes. Tiles are generally strong enough to handle the load, but mounting brackets must be carefully fitted to avoid cracking tiles under the panel weight. Most installers replace a few tiles with flashing kits to maintain weatherproofing while evenly distributing the weight.

Labour & Equipment Costs

Heavier solar panels not only require more manpower during installation but may also involve the use of lifting equipment, scaffolding, or cranes, especially for larger commercial projects. 

While this can slightly increase overall installation costs, for most residential systems the difference is minimal. The added labour is usually offset by the long-term savings on energy bills.

Long-Term Durability

Ensuring your roof can bear the weight of solar panels is critical for maintaining structural integrity over decades. An overstressed roof may suffer from sagging, water ingress, or cracked tiles. 

This is why MCS-accredited installers carry out structural surveys before installation. By confirming your roof can handle the load, you protect both the system’s efficiency and your property’s value.

FAQs 

How much does a full 4kW solar panel system weigh?

A 4kW system (around 10–12 panels) typically weighs 200–250kg in total.

Does adding solar panels increase my roof’s insurance risk?

Most UK insurers accept solar panels as long as they’re installed by MCS-certified installers, but you should notify your provider.

Can solar panels be installed on lightweight roofs like conservatories or sheds?

Conservatories and garden sheds usually can’t support panels. Instead, panels should be installed on the main house roof or ground-mounted.

Do lightweight solar panels exist for UK homes?

Yes, frameless, flexible, and thin-film panels are lighter options, but they’re less efficient and less common in the UK.

Our Verdict

So, how much do solar panels weigh? On average, each panel weighs between 18–25kg, translating to about 10–12kg per square metre of roof space. For most UK homes and commercial buildings, this is well within safe structural limits.

The key is ensuring your roof is assessed by an MCS-accredited installer who understands your property’s specific needs.

Whether you’re a homeowner, landlord, or commercial property manager, solar panel weight should not discourage you. With the right advice and installation, solar panels are a safe, efficient, and sustainable investment that can cut your energy bills and carbon footprint.