South facing roofs receive more radiation throughout the year and will produce the maximum energy output. The ideal roof will have an orientation due south. However South-East and South-West orientated roof will still produce high solar yields
Tilt of your roof
By tilting a surface to an angle the amount of solar radiation falling on it will be greater than that falling on a flat surface. The ideal tilt will have a 30° inclination. However, the inclination of the roof does not play such a decisive factor as orientation. For this reason roof inclination between 20 to 60° will be receiving most of radiation. Fortunately, the average tilt of a UK house roof is about the optimum for receiving solar energy.
Shading would have a detrimental effect on the electricity your system generates. Shading may come from trees, chimneys or surrounding buildings. Shading is a very important factor in the solar PV output. However, if your panels are partially shaded at the early morning or dawn, the system will still generate acceptable yields. Your installer will be able to assess and highlights any shading concerns and give you a realistic electricity generation potential