Rules of thumb for sizing solar panels

Whilst each solar hot water system should be designed properly, it is helpful to have a method for estimating the size of the system components. 

1. 1sqm per person - This means for each person in the household, there should be 1 square metre of flat plate solar panel area. This rule assumes a south-facing pitched roof.
2. 50Litres/sqm - For each square metre of solar panel area, there should be around 50 Litres of hot water storage in your hot water cylinder.

Example

Lets say there a 4 people in your house. You would want 2 solar panels of 2sqm each (2m x 1m). To suit this system, there should be around 200 Litres in your hot water cylinder.

Note: The system should be sized for the permanent occupants only for maximum efficiency. grossly over or under-sizing the system can reduce the efficiency.