Finding out what size solar system you need for your house depends on what you want your system to do. For many people, it is about making sure the solar system pays for itself in as little time as possible, for others it is to reduce their power bill by the greatest amount possible or to reduce their carbon footprint and do their bit for the environment.
Paying back your investment as quickly as possible requires sizing up a system to match your daytime energy usage.
In a perfect situation, you would use all of the solar power that is generated and have the solar panels facing north or (north-west to maximise your savings during the peak time of use billing period- see below for more info). For example, if you install a 5kW system for $6,200 and it generates 7118kW/h over one year if you save an average of 30 cents a kW you would save $2,135 every year.
This would result in a return on your investment of only 2.9 years! In reality, it is difficult to use 100% of the power a solar system generates, however, if the system is sized correctly you should be able to get close to 80% or higher.
Detailed Information – How to size up a solar system
Minimising your power bill is easy, simply install the largest solar system you can afford and/or fit on your roof. As mentioned above, there is a good fit for everyone but there is no harm in getting a system that is a little bigger. This can allow for future increases in power usage if you are planning on buying a pool, spa, air conditioner or some other large user of power.
The reason returns diminish when you have a larger system is that instead of saving money from your bill by using the solar power rather than buying power from the grid (eg. contracted rate of 25 cents per kWh), you are selling solar power to the grid at your contracted feed-in tariff rate (eg. 5 cents to 8 cents per kWh).
It is now possible to install solar batteries to store this excess solar power to use in the evening. Many households are now sizing up a solar system based on their total daily power usage, with the aim of running on solar power 24 hours a day. The power grid then becomes a backup for periods of bad weather. Solar storage is now for everyone, so please contact us for more information.
If you are environmentally motivated, your roof space and budget are all that are stopping you! The bigger the solar system the better, as you are reducing your reliance on polluting industries such as coal and gas and helping to produce clean, renewable energy. Buying a solar system is one of the biggest steps you can take as an individual and a household to help build the renewable energy sector and reduce our reliance on old and polluting technology. By installing a 5kW solar system you are taking around $50,000 off the books of the coal industry. There are now millions of solar systems in Australia, and as this number continues to grow our voice becomes louder – governments are starting to listen!