The prevalence of 5kW solar systems has gone down since it has become more financially viable to meet energy requirements rather than exceed them. Therefore only quite large energy consumers tend to require anything larger than a 3kW system to meet their daytime energy needs.
Key details for a 5kW system are as follows:
|Average Price ($)||How many panels?||Average Energy Generated Daily (kWh)|
|$6,100 – $10,200||20 – 27 (depending on panel size e.g. 190W)||20 units|
*Note that the energy generated daily is an average for the year; in summer this will be higher but conversely in winter it will be lower. Also this is an average across all of Australia and so there will be a variation depending on exact location.
A 5kW solar system is a considerable size for a typical household and thus, this system is more suited for households with an average daily consumption of around 28+ units per day. Generally, this would be a house of 5+ people.
Considering this from a financial perspective, the typical payback period on a 5kW system like this would be between 3.75 – 6.5 years. Realistically, if we take average pricing and energy use and also take into account the rising cost of electricity you’d expect a return on investment of approximately 4.5 years.
These figures are based on the fact that you offset your energy usage by not having to buy power from the grid. So for every unit you don’t pay for from the grid you save yourself about $0.22. This may not sound like much but over a year that adds up to about $1,650 on a 5kW system. These savings only increase if (when) the price of electricity increases.
For placing the panels of a 5kW system you have look at what your own energy use is like. The 5kW systems can be placed facing in up to 2 directions. This is because the configuration of inverters this size usually split the panels between two ‘ports’.
The typical household has low load in the middle of the day when people are at work/school and a peak in the late afternoon early evening when everyone gets home. These types of households may benefit more from facing their panels in a more westerly direction to get the peak generation closer to the evening when the most power is being used. However, if people are home during the day then it would be better to have your panels face as north as possible and peak during midday.
Alternatively you can have half panels facing west and half north and have them act like two individual 2.5kW systems. This will give a smoother power output during the day, but obviously won’t reach the same peaks as all panels facing the same direction.
In the end you want to maximise the use of the solar you generate in order to minimise how much you have to buy from the grid.