Solar panels

Solar PV cells are made from layers of semi-conducting material, usually silicon.

When light shines on the material, electrons are knocked loose, creating a flow of electricity. The cells don’t need direct sunlight to work, they can work on a cloudy day. However, the stronger the sunshine, the more electricity generated.

Solar PV cells are grouped into modules, and modules usually grouped into solar arrays – modules and arrays come in a variety of shapes and sizes.

Most PV systems are made up of panels that fit on top of your roof, but you can also install on the ground, or fit solar tiles.

The electricity generated is direct current (DC), whereas the electricity you use for household appliances is alternating current (AC). An inverter is installed along with the system to convert DC electricity to AC.

During daylight hours, you’ll be generating electricity even on cloudy days, but during the evening you’ll be using electricity from the mains. Reducing your electricity use can help lower your bills and reduce your carbon footprint. Remember to turn devices off and avoid standby, and see our energy saving quick wins for more tips to reduce your energy use.

As your PV system will be working at its peak during daylight hours, it’s a good idea to think about reorganising domestic activities such as washing, dishwashing and ironing. If you’re home most of the day, then this will be easier to do, but if you work during the day then try setting up timers for your dishwasher and washing machine.

If you have electric heating, programming your timers to come on during daylight hours will help you save money on your electricity bills. To keep that heat in your home for longer, insulate your roof or loft, and add insulation to your cavity wall or solid wall. Draught-proof your doors and windows as well to prevent draughts.

You can combine PV with other space-heating renewable technologies such as heat pumps, solar thermal systems and wind turbines. These technologies work well with each other, as PV can be set up to help power a heat pump, for example, or several of these systems can feed into a thermal store.

Most of the time your solar PV system either:

• isn’t generating enough energy for your household’s demand, and is supplemented by importing electricity from the grid, or
• is generating excess electricity surplus to your demand, and exporting that electricity back to the grid.

If you are getting export payments via Smart Export Guarantee or if you aren’t getting paid for exports at all, you might be looking for a way to use more of your generated energy within your home.

Instead of sending it to the grid, that surplus electricity could power the immersion heater in your hot water tank, storing hot water for you to use later.

A PV diverter would allow you to do this, provided you have a hot water cylinder. This is typically the lowest upfront cost option for increasing in-home use, particularly if you install at the same time as your panel installation. It is a reliable and low maintenance piece of kit that directs your excess energy to power your immersion heater, instead of exporting to the grid.

On its own, excess solar energy is unlikely to meet all of your hot water needs, but it can help reduce your bills.

If you’re interested in using PV diverter, speak with your installer. They might also suggest increasing the number of panels on your roof to provide more electricity for your hot water needs.

Other options for renewable hot water include solar water heating, or fitting a whole-house heating system such as a heat pump or biomass boiler.

Solar tiles are designed to be used in place of ordinary roof tiles. A system made up of solar tiles will typically cost about twice as much as an equivalent panel system.

Solar tile systems are not normally as cost-effective as panel systems, and are usually only considered where panels are not considered appropriate for aesthetic or planning reasons.

Solar panels were eligible for Feed-In Tariff (FIT) payments. The FIT scheme closed to new applications on 31 March 2019. If you have already installed solar PV with a MCS certificate dated on or before 31 March 2019 you may still be able to apply. For more information about the FITs scheme and recent changes please, visit our Feed-In Tariffs  page.

Please note: the Northern Ireland Renewables Obligation Certificates (NIROCs) scheme is now closed to all technologies since April 2017 and you can’t receive payments from generation tariffs any more. However, you can still cut your electricity bills by using the free electricity generated by solar PV.

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

Solar PV needs little maintenance. Keep an eye on nearby trees to ensure they don’t begin to overshadow them.

In the UK, panels that are tilted at 15° or more have the benefit of being cleaned by rainfall to ensure optimal performance. Debris is more likely to accumulate 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.

Once fitted, your installer should leave written details of any maintenance checks that you should carry out from time to time to ensure everything is working properly. This should include details of the main inverter fault signals and key trouble-shooting guidance. Ideally, your installer should demonstrate this to you at the point of handover.

Keeping a close eye on your system and the amount of electricity it’s generating (alongside the weather conditions) will familiarise you with what to expect and alert you to when something might be wrong.

The panels should last 25 years or more, but the inverter is likely to need replacing sometime during this period, at a cost of about £800.

Consult with your installer for exact maintenance requirements before you commit to installing a solar PV system.