FAQ's

What do we mean by photovoltaics? The word itself helps to explain how photovoltaic (PV) or solar electric technologies work. First used in about 1890,the word has two parts: photo a stem derived from the Greek phos, which means light, and volt, a measurement unit named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. So photovoltaics could literally be translated into light electricity, and that's just what photovoltaics materials and devices do, they convert light energy into electricity, as Edmond Becquerel discovered in the 18th century.

When certain semi conducting materials, such as kinds of silicone, are exposed to sunlight, they release small amounts of electricity. This process is known as the "photoelectric effect" .The photoelectric effect refers to the emission , or ejection , of electrons from the surface of a metal in response to light. It is this basic process that a (PV) cell converts light into electricity. Sunlight is made up of photons or particles of solar energy. Photons contains various amounts of energy, corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell they may be reflected or absorbed, or they may pass right through. Only the absorbed ones generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the PV cell which is actually a semiconductor).

A huge amount of solar energy falls every year from the sun to the Earth, we can use this energy to power electrical energy for our Homes and Businesses. The energy falls onto the panels, which creates DC electricity, an inverter then converts this into AC electricity, which is then used to run your household or business needs. For further information see our 'Match Your Roof' Page.

The size of the installation will of course depend on the size of your roof space available. STV believe that there is no such things as a one size fits all solution, and we will tailor your system to suit your property, personal needs, and financial demands. For examples on potential cost, please find your similar roof on our 'Match Your Roof' Page.

If the cost may be too much for you to afford, this does not necessarily mean  you cannot have the benefits of home generated electricity.  STV can offer you the chance to have Solar Panels installed free of charge, allowing you to greatly reduce your electricity bills.  For further information on how you can recieve Free Solar Panels, email This e-mail address is being protected from spambots. You need JavaScript enabled to view it , or call 0800 6124418.

This depends on you the consumer, obviously the less you waste the less you need. To assess your current needs add up your units consumed on your last 4 electricity bills, or contact your supplier and ask them what is your average electrical consumption is per annum. This is by far the best way to size a system rather than individual use. An average size 3 bed roomed semi detached house can produce 30-50% of its electrical needs using a 2kw system.

Your PV system does not need direct sunlight for it to work, even on cloudy days your PV system will still produce electricity. At night though, the ssytem will turn itself off.

In this case the system will allow energy to come into your home from the national grid. This will be necessary on winter days and of course night time when your PV system turns itself off.

In this case the system will export your additional electricity back into the national grid and of course you will be paid for it.

A well designed system will operate well in excess of the manufacturers 20 year warranty. The PV module with no moving parts has a lifetime expectancy of at least 30 years. STV provide our installation warranty on all installations for 5 years, and all of the products we use are covered by a comprehensive guarantee.

On a normal domestic home planning permission is not needed. However, if your home is a listed building or in a conservation area, planning permission will be needed. Those looking to install systems on commercial buildings should visit your local authorities website. STV will happily assist you in this process if you require.