Why should I look at a larger system
When I started working in the solar industry I was bombarded by a cavalcade of numbers. System sizes ranged from 1 to 40 kW and there was no direct correlation between usage and size that would work for every property. As I have become more familiar with this technology and the current market I have learned that deciding on the best-sized system is much easier than it seems and that as a whole, customers seem to be moving to larger systems to handle our increasing dependence on electricity.
The first things my experienced designers look at are roof size and orientation as well as the quarterly power usage. While we use software developed by the Australian solar council to determine a system size that would directly eliminate your power bill, we always provide the option to maximize your output in order to generate the most value out of your system. Typically if a household is spending over $300 per quarter on electricity solar makes financial sense, excluding cases where the roof is heavily shaded or currently unsuitable for solar. At this size, a customer would need a 6.6 kW system to cover the bill, however, our designers would also likely recommend investing in a larger system, feeding back into the grid to maximize production. The maximum amount of solar power a single-phase customer can feedback into the grid is 5kW, meaning that a 13kW could both protect you against future increases in usage while feeding any power not used back into the grid, meaning no power is wasted!
This logic works for any single-phase system with a power bill of over $300 per quarter, meaning that as long as you have the roof space, more solar makes sense in the long run.
If your power bill is getting up to and over the $1000 PQ mark and you are limited to a 13kW system, it may be worth looking into a 3 phase upgrade, as you would then be able to feed up to 15kW back into the grid and can install up to a 40kW system. This is a more extreme option that is definitely not suitable for every property, however, it may be worth considering if your bills are not going to be significantly mitigated by the inclusion of a single-phase system.
Recently many customers have been investing in such systems while they are subsidized by STC’s to futureproof themselves against advancements that are definitely coming our way in the near future. Most solar retailers offer a battery-ready inverter as part of their catalog, meaning that when battery technology catches up to the rest of the solar market they can be installed onto the existing system. This is significant as power security is going to be much more important when electric cars become more common over the next decade.
If you are looking to invest in a solar system, there is nothing wrong with covering your current production and nothing more. However, if you are looking at solar as an investment, purchasing a system that feeds back into the grid as well as covering your usage may be the superior choice. If you are looking into solar and want to compare the costs and benefits of each sized system, feel free to get in touch with one of our experienced solar designers here!
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