Follow these steps for guidance on how to use the calculator.
- Details of your solar panel system, such as number of panels, number of kilowatts
- Your energy bill
- Details of the overshadowing building
- if assessing the impact of a proposed development, check your council website for the detailed plans and permit application or contact the council for more information.
- if assessing the impact from an existing development, find an aerial image of your house and the neighbouring property. This can be sourced from Google Maps, Google Earth or other aerial image sources.
- the calculator assumes both properties are on flat ground and the overshadowing building is box shaped
- where the overshadowing property is at a higher elevation (slope) the overshadowing will be greater than the tool estimates.
2. Select the calculator that most closely matches the slope of your roof.
Select from the calculators on the main page above.
- Type over the pre-populated figures. These are just typical numbers included so the tool works in case you forget to add a figure.
- For help, hover your mouse above the cells showing a red mark to get more information.
- A grey triangle will appear when you click on some yellow cells. Click on this triangle and a list of options will be revealed. You’ll need to select the value that matches your situation most closely (these are pre-set options – the calculator won’t work if you try to input something else).
4. Size or capacity of your solar panel system in kilowatts (kW)
For example, a 4 kW system is equivalent to about 16 modern panels, or about 22 older pre 2015 panels.
- Standard rooftop solar system - the panels are connected to a wall-mounted appliance called an inverter.
- Micro inverter rooftop solar system – microinverters are located underneath each panel on the roof.
9. Height above panels (a)
This is the height from the bottom edge of the solar panels to the top of the overshadowing building.
The height of a building storey is generally around 3.3 metres, but this varies from just under this figure to well over it.
For situations where the overshadowing house is on much higher ground, select the next highest 'height above panels' option.
10. Horizontal distance from panels (standoff) [see (b) in diagram below]
Page last updated: 22/11/19