This section shows the estimated impact that occurs due to shading on the day of the spring equinox, 22nd September. The equinox is the date when the day and night are both 12 hours long.

For most purposes the annual impacts of overshadowing provide the best guide as to whether this shading is something you should worry about. However, planning authorities sometimes refer to overshadowing impacts on the spring equinox day, so this information may be useful.  

Estimates are provided showing the total solar generation in kilowatt-hours for both an unshaded and a shaded solar system. The percentage reduction in electricity generated is calculated too.

Image of example of Spring Equinox results

Image of example of Setback angle figures

Planning schemes define setbacks between buildings.

Standard side setbacks are equivalent to an angle of 58.8 degrees created by line drawn from the bottom of the roof (with solar panels) and the closest part of the overshadowing adjacent building.

Where there is a north facing window, the setbacks applying to the new building are greater than standard setbacks and extend for a distance of 3 metres from the edge of each side of the window.  The equivalent setback angle is 47.5 degrees

Image of setbacks of neighbouring building

Page last updated: 22/11/19