Solar energy availability in the UK is much greater than most people imagine. Indeed the UK receives on average approximately 65% of the annual radiation experienced in the South of Spain and even 55% of that experienced at the equator. The solar energy that we experience is accounted for by approximately 40% direct radiation (received when it is sunny) and some 60% diffuse, or scattered radiation (received on cloudy days).

The solar radiation received on a plane, facing the south, which is inclined at 30o (this is a typical inclination for solar collectors situated on a pitched roof in the UK), varies from about 900kWh/m2 per year in the North of the UK to approximately 1,300 900kWh/m2 per year in the South west.

Whilst the highest amounts of monthly radiation are obviously experienced in the summer months, there is enough radiation coming from the sun in spring, autumn and winter to make a very useful contribution to a household’s energy needs.