The amount of money you will save on electricity over the lifetime of the system will easily pay for the installation cost of the system, and usually pay it back a few times over. To determine the exact amount you will save on electricity, you will have to examine your electricity bill, and the size of the system you are looking to put in. If you size it large enough to provide all the electricity to you house, there will be no more electricity bills. If you have a small to medium sized, energy efficient house and put up a decent amount of collectors, you could expect to save more than 50% on your electric bills.