Woo hoo Lenny awesome stuff!! Enjoy once your smart meter goes in you can see how much you are producing and selling back to the grid.

A lot of States now have a feed in tariff (FIT) where the retailer must pay you for the production of your power. The best deals are in NSW and ACT where it is a gross tariff so you get the 4-5 times the cost of your power back for 100% of your production regardless of what you use. In the other states with a FIT you get the nett amount (i.e. the stuff you don't use in the house and feed back into the electricity grid). It means pay back times can be longer but it really depends on how power guzzling you are. Changing your appliances, making your house less leaky and changing your behaviour can help heaps regardless of whether you have solar power or not.

When we got our 1kW of solar panels put in our personal energy use went up a lot! I work in the energy efficiency/renewable energy area and still my behaviour reverted and I wasn't as careful about our energy use. We have changed that now, but be warned it may happen as you think you don't need to worry about it so much .

Kat, for $20k they would have put a large kW system in. As Suse points out the you get 5 times the Renewable Energy Certificates (REC) price (hence $ credits) for systems up to 1.5kW and any kilowatts after that just the normal 1:1 rate in credits. Depending on where you live (the credits you earn depend on where you live and how much sun your area receives), your house's orientation, whether you have shading issues and personal energy needs the price and benefits gained will differ. If you are considering a solar system its worth doing some sums to see what the best option is for you.