How are Solar Panels Installed in the UK?

Written-by

Janet Richardson

Reviewed-by

Richard Burdett-Gardiner

Updated on

Sep 29, 2024

How are Solar Panels Installed in the UK?

Let’s look at process of having solar PV (Photo Voltaic) panels installed in the UK market. 

How are solar panels installed?

In this article we’ll take a deep dive into the whole solar panel Installation process and look at a walk-through of a typical solar panel system.

Before we get into it, we need to do some housekeeping. You don't need an EPC or Energy Performance Certificate to get the Smart Export Guarantee (SEG) although it can be useful. Your property may already have a certificate and it’s easy to check. Follow this link and enter your postcode for instant results. If you can’t find your house, or the EPC has expired you can start the process of getting a new one by following this link. Please note, this is the process for England, Wales, and Northern Ireland, if your home is in Scotland there is a different process.

You will need a smart meter which is something you can organise yourself, but most people will get one installed by their energy provider. Your installation will need to be carried out by an MCS accredited installer/company who can register the system. We'll get to that later. 

Once you have a smart meter, you’ll want to contact an independent MCS accredited surveyor to look over your property.

The main duties of a surveyor are as follows:

• Determine your roof's orientation, map the inclination and work out the shade coverage.
• Estimate the approximate power output of a potential PV system based on your location and other mitigating factors.
• Project an estimate of potential savings on your current energy bills and provide a rough idea of when you’ll see a ROI.
• Check the viability of your roof including its load-bearing capability.
• Assess the wiring and other electrical infrastructure in your home. This includes your fuse box, cabling, sockets, and metering etc.
• Look at your current and future energy consumption and project future needs based on your current bills and info from your meter. 
• Discuss and explain any required District Network Operator permissions (DNO).
• Explain the benefits of guarantees and warranties.

After you have all the data you need, it’s time to look for the best quotes. Remember, no two quotes are the same. Take the time to do your due diligence. Read reviews and talk to other solar owners, and don’t forget you can use any of our tools and guides to help too.  

Once you’ve chosen your supplier, this is what you can expect next:  

• Raising scaffolding and gaining roof access – How long it takes and how involved this step is, depends on the type of house you own. It’s not rocket surgery to say bungalows need less scaffolding than three-storey buildings. If your roof is easy to access you can expect a big discount when your quotes come in. 
• Attaching the hooks to rafters – Installing solar panels often means securing them to the rafters of your home. This means removing roof tiles/slates to screw the hooks for the frame into your roof rafters. After the step, the installers will replace tiles/slates and make your roof water-tight again. This can involve adding waterproof flashing to the roof to avoid any leakages. Once again, depending on the style of roof you have this stage may involve more steps like cutting roof tiles flush. If you had a full survey, any surprises will have been explained in advance and won’t come as a shock. 
• Fix frame to hooks – With the hooks in situ, the engineers will attach the rails of the mounting frame. Next, they’re screwed together, creating the frame for the panels.
• Mounting PV panels to the frame – during this stage, the installers mount the photovoltaic cells onto the roof frame with strong clamps.
• Connecting the panels to the inverter - The DC output of the solar panels is now wired to the inverter. This is the device that converts the electricity generated by the panels into AC. AC power is what your property's electrical appliances use and also the correct format for exporting to the grid. The DC cabling is then placed underneath the roof tiles and wired to an inverter inside your property. Or, the engineers can drill a small hole through the roof slates for the cables instead. If required, waterproof flashing is then added to avoid water damage to the roof.
• Electrical wiring – After wiring the DC output from the roof array to the inverter, the cells can now generate electricity. The AC output from the inverter is now connected to your property's electricity supply and the electricity grid. At this stage the engineers can add other electrical components like AC & DC isolators for safety reasons. It’s likely the engineers will also add an Ofgem-approved generation meter. This device follows the inverter in the circuit.
• Connecting to the electricity grid - Connecting the PV system up to the grid requires your installer to work with the DNO (District Network Operator). Each region has their own provider. This is the electricity company responsible for the power grid infrastructure and not your energy provider.
• Final checks and hand over – Before signing off, your installer will perform multiple final electrical safety and performance checks. Once completed, they’ll commission the system. This gives you the green light to use the system. At this stage, the engineer will give you the required documentation. This should include any manuals, warranties, and maintenance information.
• Issue and provide MCS registration. The final step is registering your PV system with the Microgeneration Certification Scheme. At this stage, the installation is complete and you’re now part of the solar energy movement!

If you’d like to find out who your current District Network Operator (DNO) is, remember this is not your energy provider, you can follow this link. 

Is your Site Suitable for a Solar PV System?

We talked a little above about the sort of things surveyors might look for.  These include geographical and seasonal factors that can impact the efficiency and output of your Solar PV system. However, we can also just use our common sense. We all know, for example, that Southern and coastal areas receive the most sunlight in the UK. That said, it's important to add that all areas of the United Kingdom are suitable for solar energy.

Another key factor to consider is how to combat potential hurdles. Shade, for example, may affect some properties more that others. With most solar PV installations, all panels in a PV array connect to each other. So, if one panel gets less light than the others the whole system's performance suffers. If some shade is present for periods of the day or you're splitting panels up over east and west facing roofs, it may be worth considering micro-inverters. These devices are inverters that attach to each panel, allowing them to operate independently of each other. That said, for maximum efficiency and the best system output, you want a roof with little or no shade coverage. Even a little coverage can have a dramatic effect on your system‘s output. 

Lovely house, but likely unsuitable for Solar Panels

How Roof Orientation and Tilt Affects the Output and Performance of Solar Panels

For the best results, you need an unobstructed, south-facing roof with a 30° inclination from the horizontal. Although with special frames, it’s possible to install solar panels at any angle. They can even be wall-mounted or positioned on a flat roof although this will affect output and the panels self-cleaning ability. 

In the UK, most roofs tilt between 30° to 45°. That said, any roof tilt between 12° and 45° from the horizontal should allow a decent output.

As shown in the graph above, due south facing roofs are best. However, they are by no means the only suitable orientation for solar electricity generation. South-east, or south-west facing roofs can lose up to 10% or more in efficiency over south-facing roofs, but that still leaves plenty of potential energy. As we shift orientation, the output of arrays drop with east-facing and west-facing roofs providing up to 20% less generation than south-facing roofs.

If your house has an east-west facing roof, the best solution is to place panels on both sides of the roof. This compensates for the lost power to some extent, and ensures that at least part of your array gets the most solar radiation available through most the day.

You can check your roof viability by going to using our solar calculator. The link is at the top of the website header. 

How are Solar Panels Mounted?

The most common method of installing domestic PV panels is mounting them to your rafters. This is done with custom hooks, aluminium mounting frames and specialist clamps. 

When a property is over one storey high, scaffolding is essential to gain roof access as the engineers need access to work on the roof.

Mounting a solar array often requires installers to remove roof tiles or slates because they cannot bear the load of a bank of solar cells. With the slates removed, the engineers screw hooks into roof joists. The hooks for the frames help spread the weight distribution. Next, the installers clamp the PV panels to these frames before making good the roof tiles or slates and flashing.

Not all roofs are the same and techniques vary. If the panels are for a business or farm use the method may differ. It’s still possible to mount PV panels on other roof types like corrugated iron and the mounting process here is like that for domestic roofs. The real difference is that it’s sometimes possible to attach arrays directly to the roofing material itself or ballast the panels using weighted trays which the panels are fixed to. Engineers will of course take special care to ensure the roof can bear the weight of the PV array before undertaking any work.

There’s a common misconception that only sloped roofs can support solar panels. Hitting the correct angle of tilt is still essential, but engineers can compensate by using special angled frames. 

Solar panels can be installed on flat roofs. The advantage of flat roof installations is that it’s possible to adjust the mounting frames and set them at the optimal. Achieving the ideal angle amplifies the system’s output. Thanks to mounting frames engineers can pitch PV arrays at any angle and orientation. They can even face due south, regardless of the roof's orientation. On the downside, flat roof installations need more hardware, leading to bigger bills. 

How much does a Solar Array Weigh?

Solar PV panels are heavy. They can weigh between 15kg and 30kg each and depending on size and manufacturer, a 4kWh system means 10-14 panels. Most roofs can take that kind of strain, but you may find your roof needs strengthening to bear the weight. Strengthening your roof in not a quick job and the work can incur significant additional expense. It’s best to know if your roof is up to the job before you sign anything. Remember, your PV surveyor/installer should help you with this. 
 

Ground mount frame for Solar Panels

Roof hook & frame for solar panels

Fixed tile hook for solar panels

Flat Roof and Ground Mount

In Conclusion:

Solar panels offer significant savings on your energy bills. In addition, they contribute towards a more sustainable energy infrastructure. However, when considering a solar installation, it’s wise to plan everything in advance. Always get the best advice before you commit. By taking your time and following the best practices, you should end up with the best system for your money.

Remember to conduct a thorough assessment of your roof and energy requirements before looking for quotes. Also, make sure you opt for the right products and the best installer for your needs.

Getting the proper orientation and positioning for your panels, be they roof or ground-mounted is essential. It’s also worth looking at add-ons and upgrades. Check out devices like batteries, diverters, micro invertors, automatic tracking, and even pigeon netting. These can help you get the most from your system. Don’t neglect maintenance either, a well-kept system will provide more power and a better return on investment.  

Installing solar panels is a smart environmentally conscious decision. It’s also a prudent financial choice. Energy costs increase all the time while solar panels grow ever more efficient. As solar power moves from the fringes to the centre of energy production, its accessibility will only improve. Remember, the cost of electricity doubled in 2022. The result was a 50% cut in the pay-back period for solar owners. Today, the simple act of having solar panels on your property is enough to increase the value of your home. The truth is, the best time to invest is solar is always the same… it’s now.