On the money front we saved nearly $600 off our bill, partly thanks to our low usage and also the fact that we feed in over thirds of our generated power to the grid (the generous feed in tariff helps here).
It's been 6 years now since we installed our solar panels. In that time our PV system has saved us $3,104 off our power bills. That means we're half way to paying off the cost of the system (our 1.1 kW Kaneka/SMA system cost $6,460 after rebates back in 2008). Solar panels are way cheaper nowadays but the rebates and feed in tariffs are less favourable as well. We paid a lot for our system but are lucky enough to be paid 49c per kWh fed to the grid and this is guaranteed to 2020 (if the government keep their promise!). In fact I've just worked out that I'll need to buy more solar panels in 2020 otherwise my bills will go from small to fairly big. The last yearly bill would have been $493 feeding power in at 8.5 cents a kWh instead of $58! Adding more panels will be hard for us since our unshaded roof space is almost full of thin film panels, we may even need to try to sell the panels and get a whole new set of less space hungry panels...
Despite less favourable rebates and feed in tariffs these days PV is still a great investment. The table below shows estimated payback times for people in Western Australia. As you'll see huge savings can be made over 25 years and most PV systems will last up to 40 years. The payback time may be shorter for smaller systems but this is not the whole of the matter. Bills will be less with bigger systems meaning that overall savings are far greater in the long run.
Power prices have almost doubled in the last six years in WA, so now is a great time to buy PV. If you orient some panels to the east, north and west you'll maximise your use of generated power, which is a big plus under current feed in rates (8.5 cents a kWh in WA compared to 27 cents for power bought from the grid).
I'd love to hear from people about their experiences with PV and if anyone has questions on this topic please fire away.