Solar panels

1. When the sun shines on a solar panel, solar energy is absorbed by individual PV cells in the panel. These cells are made from layers of semi-conducting material, most commonly silicon.
2. The PV cells produce an electrical charge as they become energised by the sunlight.
3. This electrical charge creates a direct current (DC) of electricity.
4. The current passes through an inverter to turn it into alternating current (AC) electricity. This is the kind of current needed for household appliances.

The cells don’t need direct sunlight to work and can even work on cloudy days. However, the stronger the sunshine, the more electricity generated

Solar panel systems tend to be made up of between six and 12 panels, with each panel generating around 400 to 450W of energy in strong sunlight.

You can use our online assessment tool, Go Renewable, to find out what renewable technologies are suitable for your home.

Use Go Renewable

There are also a few things to consider before you commit to a solar panel installation:

Yes, it’s okay to install panels on flat roofs. Solar panels work best when angled towards the sun, so panels on flat roofs are normally tilted up to help maximise energy production.

It’s important that any solar panel system maintains the integrity of the roof covering to keep it watertight. For this reason, many systems are weighted down rather than fixed through the roof covering.

If you have a system that’s weighted down, the roof needs to be strong enough to deal with the added weight. If the roof isn’t strong enough, use appropriate fixings to ensure rain can’t cause any damage.

Sometimes it might be recommended to renew the roof covering so that you get the best possible roof integrity and solar panel performance. Even though it may add to the cost, the overall solution will be cheaper in the long run.

Yes, you can install panels in the garden on a suitable frame. Make sure they don’t get shaded by nearby trees and buildings, and they should face as close to south as is practical.

One advantage of mounting panels in the garden is that it’s easy to keep them clean. But you also need to be more careful about rodents and other physical damage.

Yes, you can install panels on an outbuilding. It’s important to make sure that the building roof is strong enough.

If the building doesn’t have its own electricity supply already then you should factor this in when looking at the total cost of the system.

The average domestic solar panel system is 3.5kWp and costs around £7,000.
The amount you pay is influenced by:

• the size of solar panel system
• any difficulty accessing your roof
• whether you choose solar panels or tiles
• whether you integrate the solar panels into the building

Some of the installation costs can be shared if you already have scaffolding up for roof repairs or if you’re building a new house.

The cost of ground-mounted solar panel systems is more difficult to predict, as there are more variables such as:

• the type of mounting frame
• how far away it is from your house

Costs can vary between installers and products, so we recommend getting quotes from at least three installers.

Make sure the installers you look at are MCS-certified, which ensures they adhere to a strict code of conduct. You can find installers on the MCS website.

There aren’t any specific solar panel grants. But you may be able to get funding as part of other government schemes.

For England and Wales

Get in touch with your local council or energy supplier to see if they offer funding under the Energy Company Obligation (ECO) scheme.

For Scotland

Read our advice on renewable energy funding for Scottish residents.

For Northern Ireland

Get in touch with NI Energy Advice to find out what funding options are available for you.

The amount you could save using a solar panel system depends on a few things:

• How much of the solar electricity you’re able to use yourself.
• Whether you sign up for export payments like the Smart Export Guarantee (SEG).
• Where in the UK you live, as areas further south get more direct sunlight.

Solar panels on their own offer lower electricity bills and low carbon energy. But they’re at their best when combined with other renewable technologies.

Instead of sending surplus electricity to the grid, a PV diverter switch can power the immersion heater in your hot water tank, storing hot water for you to use later. On its own, excess solar energy is unlikely to meet all your hot water needs, but it can help reduce your bills.

A PV diverter switch installation could add around £800 to your installation costs. You’ll need to replace your diverter after around 12 years.

If you’re interested in using PV diverter, speak with your installer. They might also suggest increasing the number of solar panels on your roof to provide more electricity for your hot water needs.
Here are the average annual savings when using a PV diverter with your solar panel system:

Your solar panels should last 25 years or more. But if you have a solar PV inverter, you need to replace this after around 12 years. This costs around £800, depending on system size and the manufacturer. Some inverters have online monitoring functions and can warn you by email if the system fails.

Most inverters have warranties of five years as a minimum, which you can often extend up to 15 years. Speak to your installer about the likely lifespan and benefit of an extended warranty.

You might find that a 15-year warranty costs almost as much as a replacement inverter, so consider it carefully.

Solar PV systems need little maintenance. Keep an eye on nearby trees and keep them well trimmed to minimise shading of the array where possible.

In the UK, rain will clean your panels if they’re tilted at 15 degrees or more. Debris is more likely to build up if you have ground-mounted panels, or if you live in an area with more dust in the air. In these cases, you might need to have the panels cleaned occasionally.

Your solar panel installer should leave written details of any maintenance checks that you should conduct to ensure everything is working properly. This should include details of the main inverter fault signals and key troubleshooting guidance.

Ideally, your installer should demonstrate this to you once the system has been installed. Speak to your installer for exact maintenance requirements before you commit to installing a solar PV system.

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