Updated: May 4
House 1. Panels West-South facing afternoon sun at best.
House 2. Panels North-East facing.
One home between them, but worlds apart in their systems' effectiveness and therefore their Return on Investment.
How different these two household’s experiences of Solar Hot Water be!
House 1 has a West South aspect placement of the SHW System, now illegal in Australia. With the one panel shaded from the tank at the time of this photo, around 10 am. This system wouldn't start heating from the primary source, the Sun, until 12.30 pm in Summer and 2 pm in winter.
The size of this system appears to be a 300 litre tank with one panel. One panel would heat this tank to approximately 50°C if facing North-West in the middle of Summer. With West-South facing panel a great deal less. Leaving this household running off what should be the "back up" heating. They would be using their system as an electric. Making it a costly electric hot water system, ☹I doubt they love their solar hot water.
House 2 has a North-East aspect placement of the Solar Hot Water system. This system will get Sun from as early as the Sun was up. Still not the hottest Sun, but enough to power this system from the primary source of Solar Hot Water power, the Sun. Providing this home with basically free hot water for 6-7 months of the year.
In the winter months and overcast days, having the backup booster set up to automatically top up the tank's heat to the required 65° when there's not enough Sun will ensure they have reliable on-demand hot water. Either way, as I said, worlds apart in savings or Return on Investment from house number 1.