The perfect roof for a Solar PV system is un-shaded and south facing with a pitch between 30 and 40 degrees. Having said that, even far from perfect roofs can still generate generous amounts of electricity and offer good returns with the current Feed in Tariffs. The table below shows the electricity generation varies with the orientation and pitch.
In the following circumstances it might not be a good idea to install Solar PV:
- If the roof is severely shaded by surrounding buildings, trees or other obstacles.
- If the roof has a complicated shape with items (chimneys, pipes, dormer windows) creating shadows across the roof.
- If the roof is more orientated towards north than south (this is less important if the pitch is low).
Please click on the table to enlarge.
Flat roofs are also used. The panels are typically orientated towards south getting a pitch with either an A-frame of a support tray. Ballast systems are often used to avoid roof penetration.