Solar Energy in the UK and Ireland

Solar energy in the UK and Ireland is far greater than most people imagine. In the summer, when items such as car bodies are often too hot to touch, we become aware of the sun's heat. However, even in the spring and autumn and on clear winter days we receive very useful amounts of solar energy. 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 in this country. Fortunately, the average tilt of a house roof is about the optimum for receiving solar energy.

The average property requires approximately 3,000 kWh per year for domestic water heating.

The map shows the total average solar radiation falling on one square metre surface inclined at 30° to the horizontal, measured in kilowatt hours.

These figures bring out the remarkable fact that the amount of solar energy falling on the total roof area of an average house is many times that required to provide all its heating and hot water.

We must note that there is a large difference between the radiation available in the summer and that available in winter.  Active solar heating systems will typically convert 40 to 50% of the solar energy falling on the solar collectors into useful heated water.