THE EFFECT OF TILT ANGLE AND ORIENTATION

The position that maximises the energy collected by a solar panel in the UK is facing south and tilted at an angle of 35 degrees from the horizontal.

Graph based on BS 5918, 3m2 panel, London, Demand 120l/day@55C

What many people find surprising, however is that the total energy collected in a year is not really a strong function of the direction in which the panel faces. This is especially true for panels on a roof - tilted at around 35 degrees, where the difference between facing east or west and facing due south is only around 12%. Any duopitch roof has one side facing in this region.

Next: Diminishing Returns in Energy Collected