How to buy solar panels Solar PV installation
We've filmed an installation of solar photovoltaic panels so you can see what to expect if you are considering buying solar panels. Plus, our experts answer your questions about whether your property is suitable for solar panels.
Installing solar panels
If the solar panels are to be installed on your roof, it's likely that you're going to need scaffolding erected for the installation. Make sure you check with the surveyor that there is space to install scaffolding and that the quote includes the cost of it.
Once the scaffolding is up, the panels could be installed in less than a day. Roofers will attach the fixing brackets onto the rafters of your roof - this is why a proper surveyor should go into your loft to check the integrity of the roof and the rafters. The solar panels will then be clamped onto the fixing brackets.
The picture, above right, shows a Which? member's roof undergoing installation of a 3.5kWp PV system.
Video guide: solar PV installation
To get a better idea of what you can expect when installing solar PV, watch our video below to see a solar panel installation (on a concrete tiled roof) from start to finish, and find out what's involved.
Is my home suitable for solar PV panels?
Solar PV panels are worth considering if you have a mainly south-facing roof with little or no shade, and you aren't thinking of moving home in the near future.
Although a south-facing roof would yield the best power output, a southwest or southeast-facing roof should also be fine - but you'd get less power out of the system.
How much energy you could produce with solar panels - and therefore how much money you could make - will depend on:
- The tilt angle of your roof and its orientation
- Where you live: the South West gets more sun than the North. This could impact the amount of electricity your system will generate, although not too significantly.
You can find out more in our guide called is solar pv a good investment?
What is the best roof orientation for solar panels?
The table below shows the percentage of the maximum output you will get from a solar PV system, depending on your roof orientation (south, west, east) and tilt angle (source: the Energy Saving Trust).
Most roofs in the UK are angled at between 30 degrees and 45 degrees. Solar PV panels are not recommended for roofs that face north.
You should also consider both the age of your roof and how strong it is, as PV panels are heavy.
Solar PV systems are most efficient if you use the electricity they produce during the day. So if you work all day leaving your home empty, you may not reap the full benefits of your solar panels. Shade could be a big problem for solar panels, so no panels should be installed where there is shade from trees, chimneys, walls or other obstructions.
What size of solar PV system is right for my home?
The right size for your home will mainly depend on the roof space available and how much electricity you use. We recommend that you do not buy too large a system as you cannot meet 100% of your demand with solar PV.
Make sure the surveyor understands your electricity use so that the system is sized correctly. As a guide, an average 4kWp system would cost about £5,000 to £8,000.
Before you install solar PV, read our tips and advice on what you should do, and the questions you need to ask before, during and after a visit from a solar PV installer - see our downloadable and printable solar PV installation checklist.
Do I need planning permission for solar PV?
Contact your council to see whether you need to apply for planning permission for your solar panels. You won’t need planning permission for most domestic solar panels, as long as they respect certain size criteria. However, exceptions apply for listed buildings, buildings in conservation areas and World Heritage Sites.
Do solar panels need cleaning?
Solar panels are pretty much maintenance-free and should last for at least 25 years.
Solar PV panels are self-cleaning when installed on an ideal roof slope, and should not require cleaning or only rarely. But if your roof has a fairly shallow pitch or is flat, it may accumulate bird droppings, leaves or dirt, so the solar panels will need occasional cleaning.
Are there any other maintenance or ongoing costs to consider?
Solar PV systems are relatively simple and have no moving parts, so they don't need much maintenance. However, within 25 years you’ll need to replace the inverter, which costs about £1,000 (some installers say it costs less).
What’s the best way of finding a reputable installation company?
Request a site visit with a technical survey, not a sales visit, and get at least three quotes. Ask for recommendations and addresses of installations in your local area that you could go and see.
Check the Microgeneration Certification website to ensure that your installer is MCS-certified, otherwise you can't take part in the Feed-in Tariff (FIT) scheme. To find installers recommended by other Which? members, use Which? Local.
How can I ensure the installation process goes well?
Make sure you don't end up with panels overhanging the roof. Where panels are fitted just above the existing roof, it's good practice that at least 30-40cm should be left between the last panel and the roof edge to allow for access and to minimise the risk of wind blowing the panels off the roof.
Use the Which? solar installation checklist to ensure you get a thorough survey. Before your installer draws up the plans, ask how much space they're leaving between the panel and the roof edge.