How Are Solar Panels Installed? Step By Step Guide UK

Are you considering generating free solar electricity and are wondering how solar panels are installed?

Interest in solar energy continues to grow in the UK as more homeowners and businesses seek to cut spending on rising energy costs, reduce reliance on the grid, and become more sustainable.

Ofgem, the UK’s energy regulator, increased the energy price cap by 1.2% between 1 January and 31 March 2025, and it’s forecast to go higher by around 3% in the second quarter of 2025.

Installing solar panels can cushion you from such rises and drastically reduce your energy payments by providing you with free, renewable, clean electricity to power your appliances.

You can even sell excess electricity back to the grid for extra savings! But how are solar panels installed, and how will the process impact your home and everyday life?

Quick Takeaways:

Solar panel installations start with a property assessment to determine your home’s suitability.
Most domestic solar panel installations in the UK fall under “Permitted Development.”
Selecting the right components ensures efficiency and long-term performance.
The installer prepares the roof, sets up the electrical components, and ensures the structure can support the solar panel system.
Once the preparation is complete, the actual installation can take between one and three days.

Step-by-Step Solar Panel Installation Process

Step 1: Property Assessment

Before committing to solar panels, a thorough assessment of your property is necessary to determine if installation is viable and cost-effective.

A professional installer will conduct a site survey remotely or in person to evaluate your home’s suitability. Several factors influence whether solar energy is a good fit for your home:

Roof Orientation and Tilt

The direction your roof faces plays a crucial role in how much sunlight your panels can absorb. In the UK, south-facing roofs capture the most sunlight throughout the day.

East- and west-facing roofs also work well, though with slightly lower efficiency. North-facing roofs are the least effective and are generally not recommended.

The ideal roof tilt in the UK is between 30 and 40 degrees. Too-flat roofs may require additional mounting structures to achieve the right angle, while very steep roofs might not be able to accommodate the panels securely.

Roof Condition and Space

A sturdy, durable roof is essential to support the weight of solar panels. If your roof is old or in need of repair, it’s best to address these issues before installation.

Space is another consideration. A typical UK home solar system is around 3-5kW, which requires approximately 10-16 panels. The exact number depends on the panel wattage and your household’s energy needs.

Shading and Obstructions

Shading from trees, chimneys, or nearby buildings can significantly reduce the efficiency of solar panels. Even partial shading on one panel can affect the output of an entire system. Installers may use microinverters or power optimizers to mitigate this.

Energy Consumption and System Size

Reviewing past electricity bills helps determine the required system size. The more energy you use, the larger the system should be. However, the goal is to balance production with consumption to maximize savings and efficiency.

After completing the site survey, the installer will provide you with a detailed quote. The quote will include

The total cost of the system, including installation
The number and type of solar panels recommended.
Estimated energy generation and potential savings.
Optional battery storage and its benefits.

The Energy Savings Trust recommends getting quotes from at least three different installers, so ensure you compare options and decide on the best system for your needs before proceeding to the next stage.

Step 2: Check If You Need Planning Permission

Planning permission ensures the solar panels installed don’t negatively impact the functionality or appearance of the surrounding area.

Most domestic solar panel installations in the UK fall under “Permitted Development,” meaning you’ll not need planning permission. You can install solar panels on the roof of a detached, semi-detached, and terraced house or the roof of most types of outbuildings.

However, there are exceptions:

If you live in a listed building
If you live in a flat, conservation area, or national park
If the panels protrude more than 200mm from the roof
If installing panels on the ground and the area exceeds 9m² or the panels exceed 4 metres in height

In December 2023, the government amended permitted development rights for solar equipment to allow installation on the flat roofs of domestic premises. This helps reduce delays and costs if you’re installing solar panels on a home with a flat roof.

If your solar panel installation requires planning permission, you’ll need to apply to your local planning authority before work can begin. Most councils offer pre-application consultations, so ensure you consult your local council to ensure your project is compliant.

Additionally, if you plan to export excess electricity to the grid, your system must be installed by an installer accredited by the Microgeneration Certification Scheme (MCS) to qualify for the Smart Export Guarantee (SEG).

Step 3: System Design and Choosing the Right Equipment

Once the assessment and planning stages are complete, system design plays a crucial role in determining efficiency and long-term performance. This stage involves selecting the right components and ensuring they work seamlessly together.

Related solar guides:

Determining System Size

The size of the system is based on your household’s energy consumption. Reviewing past electricity bills can help estimate the required capacity. A standard UK home typically installs a 3-5kW system, generating 2,500-4,500 kWh annually.

Solar Panel Selection

There are three main types:

Monocrystalline panels: These are the most efficient and durable panels, but they’re also the most expensive.
Polycrystalline panels: Slightly less efficient but more affordable.
Thin-film panels: Lightweight and flexible but with lower efficiency.

Inverter Selection

The inverter converts the electricity generated by the panels (DC) into usable household electricity (AC). Options include:

String inverters: Cost-effective and common but affected by shading issues.
Microinverters: Installed on each panel, allowing better efficiency.
Hybrid inverters: Work with battery storage, allowing you to store excess power.

Mounting System Design

Solar panels are typically installed using either:

On-roof systems: Panels sit on a frame mounted to the existing roof structure.
In-roof systems: Panels are integrated into the roof, giving a sleeker appearance.

Battery Storage (Optional)

Solar panels can be installed with batteries to store unused electricity for later use. This reduces reliance on the grid, which is especially useful at night or during power outages.

System Layout and Electrical Planning

The layout of the panels must be designed for optimal sun exposure. Installers plan:

The best orientation and tilt for efficiency.
Wiring routes for minimal energy loss.
Placement of the inverter and battery for easy maintenance.

Step 4: Preparing the Roof and Electrical Setup

Before installation begins, several preparatory steps are completed to ensure a smooth and safe installation process. This phase involves preparing the roof, setting up the electrical components, and making sure the structure is ready to support the solar panel system.

Roof Preparation

Scaffolding Setup — Scaffolding is erected around the property a few days before installation to provide safe access for the installation team and prevent accidents.

Roof Inspection and Repairs — The roof is examined again to confirm it can support the panels. If necessary, minor repairs or reinforcements are made to enhance durability.

Mounting System Installation — The framework holding the panels is secured to the roof using brackets and rails. These are fixed to the rafters to ensure stability and longevity.

Weatherproofing — Special waterproof seals prevent leaks where brackets penetrate the roof, ensuring long-term protection against the elements.

Marking the Panel Layout — Installers outline where each panel will be placed to maximize efficiency and minimize potential shading issues.

Electrical Preparation

Wiring Setup — Cables are routed from the panel area to the inverter’s planned location, typically through the loft or external conduits.

Generation Meter Installation — A generation meter is installed to track the electricity produced by the solar system.

Fuse Box Integration — The system is connected to the home’s consumer unit (fuse box) to enable safe electricity distribution.

This stage is essential to ensuring the system is structurally secure and electrically sound before the panels are mounted.

Step 5: Installing the Panels

Once the preparation is complete, the actual installation begins. Most installations take between one and three days, depending on your system’s size and complexity. The process involves carefully securing the panels to the mounting system and ensuring they’re correctly aligned for maximum efficiency.

The solar panels are carefully lifted and positioned onto the mounting system. They’re fixed onto the rails using clamps, ensuring they remain stable and can withstand harsh weather conditions. The installer will also adjust the panels for the best possible angle for sunlight absorption.

They’ll also connect electrical wiring between each panel in a series or parallel configuration, depending on system requirements. They also ensure proper ventilation by spacing the panels appropriately to allow airflow, which helps prevent overheating and improves efficiency.

The installer will then perform final checks, like inspecting all bolts and fastenings to ensure they’re tightly secured. They also check the wiring for proper connections and safety compliance. The entire array is also reviewed to confirm it is positioned correctly and free of obstructions.

Once this step is complete, the system is ready for inverter installation and electrical connections.

Step 6: Connecting the Inverter and Battery

With the solar panels securely installed, the next step is to set up the inverter and battery system to convert and store the electricity generated.

Installing the Inverter — The inverter is a key component of the solar panel system, as it converts direct current (DC) from the panels into alternating current (AC) for household use. It is usually mounted in a garage, loft, or utility room. Installers ensure it is placed in a well-ventilated area to prevent overheating and improve efficiency.

Connecting the Inverter to the Solar Panels — The electrical wiring from the panels is connected to the inverter, allowing the energy your panels generate to be converted for household consumption. Proper insulation and secure connections are checked to prevent faults or energy losses.

Installing the Battery Storage (If Applicable) — If you’re including a battery system, it’s installed at this stage. Batteries store excess energy generated during peak sunlight hours. Connecting the battery to the inverter allows seamless energy storage and discharge.

Connecting to the Consumer Unit — The installer will then link the inverter to your home’s consumer unit (fuse box) to integrate solar power with the household electrical system. This allows electricity to be distributed throughout the house efficiently.

Configuring the Monitoring System—Most modern inverters come with monitoring software, allowing you to track energy production and consumption in real time. The installer will configure the system to ensure you can access performance data through an app or web portal.

Once the installer secures and tests these connections, the system is ready for the final step.

Step 7: Testing and Grid Connection

After the physical installation is complete, the system must undergo rigorous testing before it can be officially switched on and connected to the grid. This step ensures everything is working safely and efficiently.

Conducting Electrical Safety Tests — A certified electrician will inspect and test all system components, including wiring, the inverter, and connections to the consumer unit. To prevent potential hazards, the system must meet UK electrical safety standards.

Obtaining Grid Connection Approval — If your system is designed to export surplus energy to the grid, you must get approval from the Distribution Network Operator (DNO). The installer will submit the necessary documentation, including the system’s specifications and test results, to the DNO. Government regulations require you to register solar system projects under 16A (3.68kW) per phase after installation, but systems exceeding this need approval before installation.

Final System Activation — Once all checks are complete, the system is switched on, and solar energy starts flowing into your home. The installer will take you through a final walkthrough and ensure you understand how to operate and maintain the system.

Receiving Certification and Documentation — The installer should also give you a Microgeneration Certification Scheme (MCS) certificate, which confirms the system meets industry standards. This certification is essential for accessing incentives like the SEG and ensuring compliance with UK regulations.

With the system fully operational, you can start enjoying clean, renewable energy while reducing your electricity bills.

Final Thoughts on How Solar Panels Are Installed

Solar panel installations in the UK follow a structured process, from assessment and planning to mounting and connection.

While professionals handle most of the work, understanding each step can ensure you make an informed decision.

Sources and References

https://www.ofgem.gov.uk/information-consumers/energy-advice-households/energy-price-cap
https://energysavingtrust.org.uk/advice/solar-panels/
https://www.legislation.gov.uk/uksi/2023/1279/pdfs/uksiem_20231279_en_001.pdf
https://www.gov.uk/government/publications/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors