solar panels on a detached house

Solar panels: a buyer’s guide

Producing your own energy is easier than ever and harnessing heat from the sun using solar panels is becoming one of the most affordable options.

By Ifeoluwa Adedeji | 10 January 2017

Generating your own power using solar panels is an exciting prospect that can help you save money as well as the environment. There’s a bit more to it than simply sticking some solar modules on your roof, so here’s how to make the most of this renewable technology.

The two main types of solar panels are photovoltaics (PVs), which provide electricity, and solar thermals, for hot water. The technology works by harnessing energy from the sun in the panels, also known as collectors, and converting it to power your domestic appliances and/or provide heating. These systems will work even on cloudy days. ‘

Solar works well whether south, east or west-facing and you don’t need planning permission to put modules on your roof unless you live in a listed building or in a conservation area,’ says Sonia Dunlop, communications and public affairs manager at the Solar Trade Association (020 3637 2945; ‘Recent evidence suggests that solar panels can add value to your home, with research by YouGov and Barclays Mortgages finding that UK buyers will pay up to £2,000 more for a house that has them.’

new-build features two sets of solar PVs that sit proud of the roof without marring its visual appeal

This new-build features two sets of solar PVs that sit proud of the roof without marring its visual appeal. Photo: Baufritz

New solar panel technology

PV PLUS Recent innovations are making solar power even more appealing, with hybrid PV and thermal versions (PVT) offering a one-panel solution. Other options are PV cladding and glass, which present a green alternative to traditional coverings and glazing. These, however, do not benefit from any government cashback.

SOLAR TILES These slate-style options and flush in-roof systems are also helping to improve the image of renewable energy and can be fitted as a replacement covering. They’re a good choice for conservation areas as they will blend in with the existing roofing material. ‘If the system will be very visible, then you could consider a building-integrated design (BIPV) such as Sunstation, which does not protrude,’ says Susannah Wood, CMO and head of residential solar at Solarcentury.

The Sunstation building-integrated photovoltaic (BIPV) system sits flush with the roof

The award-winning Sunstation building-integrated photovoltaic (BIPV) system sits flush with the roof. Photo: Solar Century

Solar photovoltaics

Q: How does it work? These panels contain cells that are made up of layers of semi-conducting material, which collect the sun’s energy. They work with an inverter, which converts the power that has been captured from a direct current (DC) to the alternating current (AC) used by appliances. And because there are no moving parts, the set-up requires little to no maintenance and is usually offered with a 20-year guarantee.

Q: How many panels? Homeowners typically install a 3kW or 4kW array and the industry norm is 250W per module, which equates to 12 or 16 panels on the roof. ‘A lot of the power produced can be exported rather than used in the home. If you can balance the system through east-, west- and south-facing roofs, you can get good power output throughout the course of the day and at peak load times,’ says David Mochrie, account manager at Viridian Solar (01480 831 501;

Q: How much will it cost? The price for a 4kW in-roof array starts from around £5,000 excluding installation, which takes a day and can come in at around £4,000. ‘The cost of a solar PV system has fallen by 70per cent over the past five years, and the average installation now pays for itself in just over 10 years, and continues to generate electricity for another 15 to 20 years after that,’ says Sonia Dunlop. You could also consider adding battery storage, which allows you to retain the electricity produced and use it in the evening rather than send it to the grid. This technology is still fairly new and can cost around £10,000. You can also buy smart appliances that automatically adjust their power usage to when the sun is shining.

Q: What will I get back? Thanks to the Government’s cashback incentive, PV panels have increased in popularity. The Feed-in-Tari (FIT) enables you to receive a fixed rate for every kilowatt hour (kWh) of energy that you produce – currently set at 4.32p per unit – plus a payment of 4.91p for every unit that you export to the grid. To qualify for the best rate, your home must achieve an EPC rating of D or above before the panels are commissioned. The modules and the installer must be approved by the Microgeneration Certification Scheme (MCS).

The Greenskies Solar Lifestyle flat plate panels from Worcester Bosch are highly efficient and versatile

The Greenskies Solar Lifestyle flat plate panels from Worcester Bosch are highly efficient and versatile

Solar thermals

Q: How does it work?  The modules can be either flat plate or evacuated tube collectors, which absorb warmth and transfer it to a twin-coil, hot-water cylinder via a heat transfer liquid. Flat plate arrays are generally considered the cheaper version to install, while evacuated tubes tend to perform slightly better. ‘Some solar thermal systems use a glycol solution, which will deteriorate over time and requires flushing out,’ says David Mochrie. ‘This is pretty straightforward and could even be a DIY job, otherwise you could hire a professional to complete the task.’

Q: How many panels? It’s important to ensure that your set-up will meet the domestic hot water demands for the number of people in the house. The general advice is to install one square-metre panel per person. Note that in winter you are likely to need to supplement the panels with another source such as a heat pump or a boiler – if you have a combi boiler it may not be compatible with a solar thermal array but can usually be adapted.

Q: How much will it cost? An integrated system that could generate the majority of the domestic hot water for a family of four would be in the region of £4,000 excluding the cylinder and installation fees.

Q: What will I get back? The Renewable Heat Incentive scheme pays out per kWh every quarter for a period of seven years, based on estimated system performance completed as part of a MCS installation. The current rate is 19.74p per kWh.