Is a South Facing Roof Bad for Solar Production in Adelaide

Solar System 6.6 kw

A 6.6kw Solar System - some panels facing South

“I want to put up a 6.6kw solar system on my roof, it faces north, how much is it”.

Before we come out let’s have a look at your roof space and see how much we can fit.
Not much room up there we can only fit about 10 by 330-watt panels giving you 3.3kw’s, you don’t have enough room east or west, but your south roof we can fit another 10.

“You can’t face them south”


Daily Solar Irradiation on a plane - Maximum Solar Output

To start things off we look at “annual daily irradiation on an inclined plane expressed as % of maximum value for Adelaide”. A document I use when working out a homes estimated PV output.
Look at the data for say a house at 0 degrees (north) with a roof pitch of 30 degrees.
The data gives me 100%

Then we look at a 270-degree orientation south roof with a 30-degree roof pitch
The data gives me 64%

“OK, so what will it produce”

Glad you asked
We will start with the 3.3 kW on the north roof. On average the 3.3kw facing north will produce
14.19 KW per day on average over a 12-month period
The 3.3 kW on the south roof will produce 9.08 KW per day on average over a 12-month period.

So, in total, this system will produce for you 23.27 KW per day on average over a 12-month period.

Not exactly what you were hoping to get Mr Customer but in reality, you are only missing out on a tad over 5 KW per day, you are still getting your 6.6 KW system and reducing your power significantly more than you would with just the 3.3 KW on your north roof.

“OK let’s do it”