Solar Calculator
How do you know what size system is right?
Let us explain it this way… Energy in your home, is just like money… The amount of money you have at the end of the week depends on two things
(1) how much money you made and (2) how much you spent.
Here is a quick example. Let’s say that you don’t currently have a solar system, and you get a quarterly bill from your energy company for $400. So every quarter you ‘make’ $0 of energy and ‘spend’ $400 of energy. In this example you would be out of pocket $400 a quarter. You are considering getting a solar system to help either cover some or all of your bill and you are weighing up how much to spend for the different systems.
So the energy game all about increasing the amount you make, while decreasing the amount you spend. The more make and the less you spend the better off you and the planet will be.
So when you are trying to select a system size what you really are trying to do is to find the right balance between:
- Work out how much energy are you currently using per day in kilo watt hours (for example 15 kw hours per day). You can do this by taking a look at your energy bills. You should be able to find either an average daily kilo watt hour usage for the period or a total kilo watt hour usage figure. If you only have a total then divide the total by the amount of days for the length of the bill to work out an average daily amount. It should be somewhere between 10-20 kilo watt hours per day roughly.
- Work out how much you might be able to reduce this by with some smart energy savings. So rather than falling into a trap where you think you need to invest a lot of money in a large system that can make $400 a month in energy, its smart to first look at how you can reduce your current energy spending. See the information on How To Reduce Your Energy Usgae for more info. You may be able to reduce your bill by 10-40 % by following some fairly simple measures.
- Work out what your new usage would be once you have made the savings. So let’s take a reduction of 25% for example, which would mean that your new daily usage would be 11.25 kw hours per day (15 kwh – 25% of 15 = 3.75)
- Work out what size system you would need to cover 100% of your new usage, depending on where you live by using the following chart.
- The next step is to consider the ongoing feed I tariffs for each system and get a sense of how much energy you would be likely to feed back into the grid, and how much you would get in terms of feed in tariff incentives for your particular state. (Remember some states like NSW and ACT are Gross figures, which means that you receive the feed in tariff for all the energy your system creates, and all the other states are Net, which means you receive the feed in tariff credits only on the amount of energy that you are able to export back to the grid during the day when the system is generating energy.
So if you live outside NSW and the ACT it is particularly important to look at how you can minimise your energy usage during the time when the sun is shining on your roof, from say 11:00 am to 4:00 pm for example. The more you can cut down your usage during the day then the more you will export back to the grid and the greater amount of benefit you will get.
