Most of the time most of us just grab a bill and compare the price of the solar system that is being quoted and and the calculations are done on that alone. Some people get the old there quotes and get the one in between or go the other ways with the most expensive thinking that will be the best and in Australia we have installed more cheap solar systems than any other country in the world.
Meaning that most people will never see a return as the system will not perform as the system was intended to or last the warranty period. I have worked in the insolvency industry and most warranties are not worth the paper they are printed on. In a few years we will see more unhappy Australians on top of the ones who have already figured it out that they were scammed. The reason most Australians had the wool pulled over their eyes as the systems being connected to the grid hides all the faults and errors and it takes time or education to figure out and monitor the performance of the system to see if it is doing what it was sold to do. Most people have it installed and then see how much it saved them on their bill and do the calculations from that. The problem with doing it this way is most of the retailers do not put on your bill what was produced and self consumed.
You will only see on the bill what was feedback to the retailer and how much you was paid for the feed in tariffs. It is important you have a look on the inverter and see what has been produced and do that adding and subtracting required.
The key to seeing if solar is financially viable for you is to forget about the cost of the charges from your supplier and working out what it would take to create and store all the energy required to look after your energy requirements.
The best thing to learn and understand is your load and when do you consume your energy time of day. If your thinking of staying connected to the grid or adding storage it's the most important thing you can do either way.
The reason it's important to understand when you use your energy is so that when your not producing it yourself you know where you are getting it from. It Just doesn't make sense to sell all your energy your created to the grid for a wholesale rate and buy it back at retail a few hours later.
The great thing about learning and understanding what time of day you use your energy is if you are installing batteries you can install a smaller bank just to get you over night.
There are lots of tricky things you can do with solar systems. I will give you an example of how my place works.
I would say we are off the grid completely and we still have the grid connected and yes we do you it. We currently have a really large Air con unit our oven and my welder connected to the grid. This allowed me to be completely self sufficient 95% of the year for our energy needs and the times which we want to use these three items we can.
Our plan over time is to buy a 2nd turbo oven and that will sort family xmas out. We are replacing our large Aircon with a Solar powered Air con from Solar Air and that will allow us to run all our Aircons from our batteries and the welder we will still just run from the grid for the time being.
We have chosen to stay connected to the grid for the reason of resale value and also we are a demonstration site, which means we are always playing around and teaching people how to install their own systems. Having the grid there allows us with the flick of a switch to just go back if we ever require when we run workshops and require to turn of the system to work with students and my wife can still make us all lunch.
We spent two years making our home energy efficient before installing batteries as the less energy you require to create and store the quicker you will see a return. People always as home much it cost for us to go solar and this is what I explain.
It cost me nothing to get my daily load from 30 kwhs to 18kwh. Its cost us a couple of hundred dollars changing lights and a few small things to get it down to 12kwh per day. Its cost us $7000 to get it from 12kwh per day to 5kwh and then $23,000 to get rid of the last 5kwh per day.
If you look at it this way we would have spent $30,000 over the next ten years if we would have done nothing and that's not taking into account price rises on electricity which you can see the prices due to increase at AEMO . by doing what we have done we will have our money back in ten years and also our energy usage has gone up because we produce more than we use so we started using it as we were creating it.
We also installed life time batteries which are Nife Cells so we won't be replacing our batteries every ten years.
The best thing to do financially is understand your load and reduce it 1st and leave and then educate yourself about how it all works. Energy is not a one size fits all type of industry and by having grid feed inverter and playing silly games with prices and feed in tariffs it has got a lot of people to install these systems which will learn some expensive lessons when all the rebates finish about how electricity works.