Solar panel installation
Considering buying solar panels? Watch our video to find out what happens when solar panels are installed, and learn whether your home is suitable for solar.
The picture above shows a Which? member's roof undergoing installation of a 3.5kWp solar PV system. Keep reading to find out all you need to know about solar panel installation, to watch our solar installation video and download our free solar PV installation checklist.
Installing solar panels
If the solar panels are being installed on your roof, you're probably going to need scaffolding. Make sure you check with the surveyor that there is space to install scaffolding and that the cost is included in your quote.
Once the scaffolding is up, the panels could be installed in less than a day. Roofers will attach the fixing brackets on to 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 on to the fixing brackets.
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're not 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 would get less power out of the system, and be able to save less on your electricity bill.
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, for instance, and this could affect the amount of electricity your system will generate, although not too significantly.
Solar panel owners in Wales, the East Midlands and South West England reported their solar panels generating the highest amounts, on average.
Two thirds (67%) of solar panel owners in Wales said their system generated more than 3,000kWh per year. Some 61% in the East Midlands and 60% in the South West said the same. But just a quarter (25%) of solar panel owners in London had solar pv systems generating this much.
Bear in mind that the size of the system is a big factor affecting potential generation, as well as geographical location. Those in London were also most likely to have the smallest solar pv systems. Some 15% have systems with a maximum generation of 1.5kWp, compared with 3% on average across the rest of the UK.
But in Scotland, two-thirds (66%) of solar pv owners had a system of 3.6-4kWp but less than half (48%) say their system generates more than 3,000kWh of electricity per year.
We surveyed 1,987 Which? members with solar panels in May 2019.
What is the best roof direction 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 (west, south, east) and tilt angle (source: the Energy Saving Trust).
Most UK roofs are angled at between 30 degrees and 45 degrees. Solar PV panels are not recommended for roofs that face north.
You also need to 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. Do consider whether nearby trees are likely to grow and overshadow your roof.
How many solar panels do I need 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 don't buy too large a system, as you can't meet 100% of your demand with solar PV.
Make sure the surveyor understands your electricity usage so you get the right-sized system for your needs and budget. As a guide, an average 4kWp system would cost between £5,000 and £8,000.
Before you install solar PV, read our tips and advice on what you should do and the questions you need to ask a solar PV installer. See our free downloadable and printable checklist:
Do I need planning permission for solar panels?
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're below a certain size.
However, exceptions apply for listed buildings, buildings in conservation areas and World Heritage Sites.
Are there other solar panel maintenance or ongoing solar panel costs?
Solar panels are pretty much maintenance-free and should last for at least 25 years.
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 between £900 and £1,600 on average if you get a professional in, or between £500 and £1,200 if you fix it yourself, according to our recent survey.*
Some 12% of solar panel owners we surveyed in May 2019 said they had had a problem with their inverter since their system was installed. These problems typically occurred between three-and-a-half and four-and-a-quarter years after installation.
Once you’ve had solar panels installed, your installer should give you written details of any maintenance checks you need to carry out occasionally to check your system is working properly.
How can I find the best solar panel 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. You can use Which? Trusted Trader to find trustworthy local recommended by other solar panel customers.
It's a good idea to choose an installer who is Microgeneration Certification Scheme-certified. You can check this on the . To qualify for the , and earn money for generating renewable energy, you had to use an MCS installer. The feed-in tariff is now closed to new applicants, however.
How can I ensure my solar installation 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 to leave at least 30-40cm between the last panel and the roof edge to allow for access and to minimise the risk of strong wind blowing the panels off.
*Online survey of 1,987 Which? Connect members with solar panels in May 2019.