How does it all work?

Orientation

In the northern hemisphere collectors should ideally face south. Surfaces which face south receive more solar radiation than surfaces with other orientations. This is because the Sun is highest in the sky and therefore strongest at solar noon. However, orientations between 30° east and 40° west of south are acceptable and will not result in more than 10% loss in efficiency compared with the ideal situation. The graphs below shows the total average solar radiation falling on 1m² surface, inclined at 30° to the horizontal, mesaured in kilowatt-hours. The average property requires approximately 3,000 kWh per year for domestic water heating.

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